Dr Ross Norris

Dr Ross Norris

Advisor - Clinical Pharmacology Laboratory

School of Medicine and Public Health

Career Summary

Biography

A/Prof Ross Norris (PhD MAppSc BAppSc) is an analytical chemist in drug analysis, primarily supporting dose individualisation of therapeutic drugs, though he has expertise and experience in a range of applications of analytical chemistry, particularly related to drugs and/or toxins and the use of tandem mass spectrometry coupled to high performance liquid chromatography.

He currently holds the research position of Advisor, (Clinical Pharmacology Laboratory), Clinical Pharmacology, School of Medicine & Public Health, University of Newcastle, Australia, He was the Chief Scientist in the therapeutic drug monitoring (TDM) Laboratory in the Dept of Clinical Pharmacology, Princess Alexandra Hospital, Brisbane, Australia from 1985 to 1997, moving into research after completing his PhD in 2002. In 2002 he took up the joint positions of Research Consultant, Australian Centre for Paediatric Pharmacokinetics and Senior Scientist, Therapeutic Advisory Service, Mater Health Services Brisbane Australia. March 2014 saw a move to Sydney to take up the role of Scientific Head, Clinical Pharmacology, Sydpath, Sydney, Australia. In March 2018 A/Prof Norris moved to his present role in medical cannabis and other clinically related research. He has chaired both the Special Drugs Working Party, Royal College of Pathologists of Australasia, Quality Assurance Program and the Standards of Practice Committee, International Association of TDM and Clinical Toxicology (IATDMCT) and led a biennial ANZ TDM meeting from 2010 to 2014. He also led a successful bid to have the 16th IATDMCT congress held in Brisbane in 2018, participating for a time as co-chair of the organising committee.

He has published more than 80 papers, 2 book chapters and 2 letters to editors primarily in TDM. Based on his skills and abilities, his current passion is the promotion of best-practice individualised drug dosing with the aim of improving both patient care and cost-effectiveness of drug therapy.


Qualifications

  • Doctor of Philosophy, University of Queensland
  • Bachelor of Applied Science (Applied Chemistry), Queensland Institute of Technology
  • Master of Applied Science, Queensland Institute of Technology

Keywords

  • Clinical Pharmcology
  • Drug analysis
  • Pathology

Fields of Research

Code Description Percentage
111502 Clinical Pharmacology and Therapeutics 60
110316 Pathology (excl. Oral Pathology) 40

Professional Experience

UON Appointment

Title Organisation / Department

Awards

Professional

Year Award
2011 NHMRC Ten of the Best Research Projects - 2011
NHMRC (National Health & Medical Research Council)
Edit

Publications

For publications that are currently unpublished or in-press, details are shown in italics.


Journal article (74 outputs)

Year Citation Altmetrics Link
2019 Gould M, Ginn AN, Marriott D, Norris R, Sandaradura I, 'Urinary piperacillin/tazobactam pharmacokinetics in vitro to determine the pharmacodynamic breakpoint for resistant Enterobacteriaceae', International Journal of Antimicrobial Agents, 54 240-244 (2019) [C1]

© 2019 Urinary tract infections caused by multidrug-resistant Enterobacteriaceae are a growing burden worldwide. Recent studies of urinary pharmacokinetics described high piperaci... [more]

© 2019 Urinary tract infections caused by multidrug-resistant Enterobacteriaceae are a growing burden worldwide. Recent studies of urinary pharmacokinetics described high piperacillin/tazobactam (TZP) concentrations in urine, but it is unknown whether this results in treatment efficacy. This study investigated the pharmacodynamics of TZP in a static in vitro model for Enterobacteriaceae to determine the concentration¿effect relationship and ultimately the required free (unbound) time above the minimum inhibitory concentration (fT>MIC) required for bacterial killing. The static simulation model investigated TZP fT>MIC between 0% and 100%. Resistant Escherichia coli and Klebsiella pneumoniae isolates with piperacillin/tazobactam MICs of 4096/512, 1024/128 and 128/16 mg/L were investigated; two of the three organisms were carbapenemase-producers. Clinical efficacy was determined as a 3-log reduction over the dosing interval by comparing interval growth with controls. TZP was observed to exhibit time dependence for all organisms. The fT>MIC was determined to be 37.5%, 37.5% and 50% for MICs of 4096/512, 1024/128 and 128/16 mg/L, respectively. Linear regression identified the overall target to be 49.85 ± 16.9% fT>MIC. In conclusion, bactericidal activity against TZP-resistant Enterobacteriaceae occurred at 49.85 ± 16.9% fT>MIC. This suggests that highly resistant urinary organisms, including carbapenemase-producers, with MICs up to 4096/512 mg/L could be treated with TZP. Further investigations are required to elucidate urinary breakpoints and to explore the impact of different resistance mechanisms.

DOI 10.1016/j.ijantimicag.2019.05.013
Citations Scopus - 1Web of Science - 1
2019 Kamel B, Williams KM, Graham GG, Norris RLG, Stocker SL, Carland JE, et al., 'Determination of febuxostat in human plasma by high performance liquid chromatography (HPLC) with fluorescence-detection', Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences, 1126-1127 (2019) [C1]

© 2019 Elsevier B.V. Febuxostat prevents gout attacks by lowering serum urate. Aspects of the pharmacokinetic-pharmacodynamic relationship of febuxostat concentrations to urate in... [more]

© 2019 Elsevier B.V. Febuxostat prevents gout attacks by lowering serum urate. Aspects of the pharmacokinetic-pharmacodynamic relationship of febuxostat concentrations to urate in gout patients need further elucidation. In order to undertake these studies, the assay methodology for febuxostat has been enhanced and validated to meet FDA standards. An HPLC method with fluorescence-detection has been modified to increase sensitivity, reduce complexity, shorten the sample preparation process and improve the inter-day coefficient of variation of the lowest quality control sample (0.03 µg/L). Protein in plasma samples (200 µL) is now precipitated with acetonitrile (400 µL) containing the internal standard (2-naphthoic acid). The supernatant is analysed at excitation and emission wavelengths of 320 and 380 nm, respectively as in the previous method. A Luna C18 column (Phenomenex, Australia) at 40 °C with mobile phase of glacial acetic acid (0.032%) in acetonitrile:water (60:40, v:v), an injection volume of 10 µL and a flow rate of 1.5 mL/min is employed. Analysis time is 8 min. Calibration curves in drug-free plasma range from 0.005 to 10.00 µg/mL. Data points are fitted using linear regression with a weighting factor of 1/concentration. The inter-day accuracy and imprecision of the quality control samples (0.0075, 0.015, 3.00 and 9.80 µg/mL) is 90¿115% and = 14.5%, respectively.

DOI 10.1016/j.jchromb.2019.121764
2018 Duley JA, Ni M, Shannon C, Norris RL, Sheffield L, Cowley D, et al., 'Preliminary evidence for enhanced thymine absorption: A putative new phenotype associated with fluoropyrimidine toxicity in cancer patients', Therapeutic Drug Monitoring, 40 495-502 (2018) [C1]

Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. Background: Chemotherapy for colorectal, head and neck, and breast cancer continues to rely heavily on 5-fluorour... [more]

Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. Background: Chemotherapy for colorectal, head and neck, and breast cancer continues to rely heavily on 5-fluorouracil and its oral prodrug capecitabine. Associations of serious fluoropyrimidine adverse effects have focused on inherited deficiency of the catabolic enzyme, dihydropyrimidine dehydrogenase. However, abnormal dihydropyrimidine dehydrogenase activity accounts for only about one-third of observed toxicity cases. Thus, the cause of most fluorouracil toxicity cases remains unexplained. Methods: For this small cohort study, thymine (THY) 250 mg was administered orally to 6 patients who had experienced severe toxicity during treatment with 5FU or capecitabine. Plasma and urine were analyzed for THY and its catabolites dihydrothymine (DHT) and bureidoisobutyrate. Results: Of the 6 patients, 2 had decreased THY elimination and raised urinary THY recovery consistent with inherited partial dihydropyrimidine dehydrogenase deficiency, confirmed by DPYD sequencing. Unexpectedly, 3 patients displayed grossly raised plasma THY concentrations but normal elimination profiles (compared with a normal range for healthy volunteers previously published by the authors). DPYD and DPYS sequencing of these 3 patients did not reveal any significant loss-of-activity allelic variants. The authors labeled the phenotype in these 3 patients as "enhanced thymine absorption". Only 1 of the 6 cases of toxicity had a normal postdose plasma profile for THY and its catabolites. Postdose urine collections from all 6 patients had THY/DHT urinary ratios above 4.0, clearly separated from the ratios in healthy subjects that were all below 3.0. Conclusions: This small cohort provided evidence for a hypothesis that fluorouracil toxicity cases may include a previously undescribed pyrimidine absorption variant, "enhanced thymine absorption," and elevated THY/DHT ratios in urine may predict fluorouracil toxicity. A prospective study is currently being conducted.

DOI 10.1097/FTD.0000000000000532
Citations Scopus - 1Web of Science - 1
2018 George R, Haywood A, Khan S, Radovanovic M, Simmonds J, Norris R, 'Enhancement and Suppression of Ionization in Drug Analysis Using HPLC-MS/MS in Support of Therapeutic Drug Monitoring: A Review of Current Knowledge of Its Minimization and Assessment', THERAPEUTIC DRUG MONITORING, 40 1-8 (2018)
Citations Scopus - 8Web of Science - 13
2018 Imani S, Buscher H, Day R, Gentili S, Jones GRD, Marriott D, et al., 'An evaluation of risk factors to predict target concentration non-attainment in critically ill patients prior to empiric ß-lactam therapy', European Journal of Clinical Microbiology and Infectious Diseases, 37 2171-2175 (2018) [C1]

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. To determine whether target concentration non-attainment can be anticipated in critically ill patients prior to init... [more]

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. To determine whether target concentration non-attainment can be anticipated in critically ill patients prior to initiating empiric ß-lactam antibiotic therapy based on readily available clinical factors. Retrospective review of consecutive patients treated with piperacillin or meropenem and who underwent therapeutic drug monitoring (TDM) at St Vincent¿s Hospital (Sydney, Australia) between January 2013 and December 2015 was performed. Predefined subgroups were patients who received continuous renal replacement therapy (CRRT) and those who did not (non-CRRT). Potential risk factors were evaluated by correlation with ß-lactam antibiotic trough concentrations (Cmin) lower than or equal to targeted minimum inhibitory concentration (MIC). Only the first drug concentration after initiation of the antibiotic treatment was included to reflect empirical dose selection. A total of n = 249 patients (piperacillin, n = 169; meropenem, n = 80) were investigated. For non-CRRT patients (n = 210), multivariate analysis demonstrated the following: male gender (p = 0.006); younger age (p = 0.015); prescribed daily antibiotic dose less than 1.5 times the product information recommendations (p = 0.004); lack of positive microbiology (p = 0.006); lower overall illness severity (p = 0.005); and estimated glomerular filtration rate (eGFR) = 90¿mL/min/1.73¿m2 (p < 0.001), to be associated with Cmin = MIC. No predictor variable was found to be significantly associated with Cmin = MIC for the CRRT cohort. Evaluating the risk of target concentration non-attainment using simple clinical factors is possible at the bedside for non-CRRT patients prior to empiric antibiotic initiation. Clinicians should be wary of selecting doses based on the product information especially when treating younger male patients with apparently ¿normal¿ renal function.

DOI 10.1007/s10096-018-3357-9
Citations Scopus - 2Web of Science - 3
2017 Kunarajah K, Hennig S, Norris RLG, Lobb M, Charles BG, Pinkerton R, Moore AS, 'Population pharmacokinetic modelling of doxorubicin and doxorubicinol in children with cancer: is there a relationship with cardiac troponin profiles?', CANCER CHEMOTHERAPY AND PHARMACOLOGY, 80 15-25 (2017)
DOI 10.1007/s00280-017-3309-6
Citations Scopus - 6Web of Science - 7
2017 Kunarajah K, Hennig S, Norris RLG, Lobb M, Charles BG, Pinkerton R, Moore AS, 'Population pharmacokinetic modelling of doxorubicin and doxorubicinol in children with cancer: is there a relationship with cardiac troponin profiles? (vol 80, pg 15, 2017)', CANCER CHEMOTHERAPY AND PHARMACOLOGY, 80 27-28 (2017)
DOI 10.1007/s00280-017-3338-1
2017 Khan S, Heussler H, Mcguire T, Dakin C, Pache D, Cooper D, et al., 'Melatonin for non-respiratory sleep disorders in typically developing children', Cochrane Database of Systematic Reviews, 2017 (2017)

© 2017 The Cochrane Collaboration. This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the effects of melatonin for non-respiratory s... [more]

© 2017 The Cochrane Collaboration. This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the effects of melatonin for non-respiratory sleep disorders in typically developing children, with regard to improvement in sleep initiation, sleep maintenance and sleep scheduling, when compared with placebo, other medication for sleep disorders, psychological/behavioural therapy, light therapy or no treatment.

DOI 10.1002/14651858.CD009141.pub2
Citations Scopus - 3
2017 Khan S, Heussler H, Mcguire T, Dakin C, Pache D, Cooper D, et al., 'Melatonin for non-respiratory sleep disorders in children with neurodevelopmental disorders', Cochrane Database of Systematic Reviews, 2017 (2017)

© 2017 The Cochrane Collaboration. This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the role of melatonin for non-respiratory slee... [more]

© 2017 The Cochrane Collaboration. This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the role of melatonin for non-respiratory sleep disorders in children with neurodevelopmental disorders for improvement in sleep initiation, sleep maintenance and sleep scheduling when compared with either placebo, other medication for sleep disorders, psychological/behavioural treatment, light therapy or no treatment.

DOI 10.1002/14651858.CD009140.pub2
Citations Scopus - 4
2017 George R, Haywood A, Good P, Hennig S, Khan S, Norris R, Hardy J, 'Can Saliva and Plasma Methadone Concentrations Be Used for Enantioselective Pharmacokinetic and Pharmacodynamic Studies in Patients With Advanced Cancer?', CLINICAL THERAPEUTICS, 39 1840-1848 (2017)
DOI 10.1016/j.clinthera.2017.07.044
Citations Scopus - 2Web of Science - 2
2017 Leshinsky J, McLachlan A, Foster DJR, Norris R, Barrs VR, 'Pharmacokinetics of caspofungin acetate to guide optimal dosing in cats', PLOS ONE, 12 (2017)
DOI 10.1371/journal.pone.0178783
Citations Scopus - 1Web of Science - 2
2016 Barras MA, Serisier D, Hennig S, Jess K, Norris RLG, 'Bayesian Estimation of Tobramycin Exposure in Patients with Cystic Fibrosis', ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 60 6698-6702 (2016)
DOI 10.1128/AAC.01131-16
Citations Scopus - 11Web of Science - 11
2016 Lindsay PJ, Bond SE, Norris R, Marriott DJE, Miyakis S, 'Posaconazole Therapeutic Drug Monitoring in a Regional Hospital Setting', THERAPEUTIC DRUG MONITORING, 38 804-807 (2016)
DOI 10.1097/FTD.0000000000000334
Citations Scopus - 3Web of Science - 3
2016 George R, Lobb M, Haywood A, Khan S, Hardy J, Good P, et al., 'Quantitative determination of the enantiomers of methadone in human plasma and saliva by chiral column chromatography coupled with mass spectrometric detection', TALANTA, 149 142-148 (2016)
DOI 10.1016/j.talanta.2015.11.044
Citations Scopus - 6Web of Science - 7
2016 Bista SR, Haywood A, Hardy J, Norris R, Hennig S, 'Exposure to Fentanyl After Transdermal Patch Administration for Cancer Pain Management', JOURNAL OF CLINICAL PHARMACOLOGY, 56 705-713 (2016)
DOI 10.1002/jcph.641
Citations Scopus - 4Web of Science - 3
2016 Duley JA, Ni M, Shannon C, Norris RL, Sheffield L, Harris M, et al., 'Towards a test to predict 5-fluorouracil toxicity: Pharmacokinetic data for thymine and two sequential metabolites following oral thymine administration to healthy adult males', EUROPEAN JOURNAL OF PHARMACEUTICAL SCIENCES, 81 36-41 (2016)
DOI 10.1016/j.ejps.2015.10.001
Citations Scopus - 10Web of Science - 10
2015 Lim AE, Tate JR, Clarke D, Norris RL, Morris RG, Martin JH, 'Clinical Consequences of a Miscalibrated Digoxin Immunoassay', THERAPEUTIC DRUG MONITORING, 37 104-109 (2015) [C1]
DOI 10.1097/FTD.0000000000000118
Citations Scopus - 1Web of Science - 1
Co-authors Jen Martin
2015 Bista SR, Haywood A, Hardy J, Lobb M, Tapuni A, Norris R, 'Protein binding of fentanyl and its metabolite nor-fentanyl in human plasma, albumin and alpha-1 acid glycoprotein', XENOBIOTICA, 45 207-212 (2015)
DOI 10.3109/00498254.2014.971093
Citations Scopus - 10Web of Science - 9
2015 Hennig S, Norris R, Tu Q, van Breda K, Riney K, Foster K, et al., 'Population Pharmacokinetics of Phenytoin in Critically Ill Children', JOURNAL OF CLINICAL PHARMACOLOGY, 55 355-364 (2015)
DOI 10.1002/jcph.417
Citations Scopus - 3Web of Science - 3
2015 Bista SR, Haywood A, Norris R, Good P, Tapuni A, Lobb M, Hardy J, 'Iron Chelation in Thalassemia Major', CLINICAL THERAPEUTICS, 37 2882-2883 (2015)
DOI 10.1016/j.clinthera.2015.11.002
Citations Scopus - 6Web of Science - 5
2015 Bista SR, Hardy J, Tapuni A, Fu J, Gibbons K, Good P, et al., 'Validation of a Fentanyl Transdermal Adhesion Scoring Tool for Use in Clinical Practice', JOURNAL OF PAIN AND SYMPTOM MANAGEMENT, 49 934-938 (2015)
DOI 10.1016/j.jpainsymman.2014.09.017
Citations Scopus - 4Web of Science - 2
2015 Bista SR, Haywood A, Norris R, Good P, Tapuni A, Lobb M, Hardy J, 'Saliva versus Plasma for Pharmacokinetic and Pharmacodynamic Studies of Fentanyl in Patients with Cancer', CLINICAL THERAPEUTICS, 37 2468-2475 (2015)
DOI 10.1016/j.clinthera.2015.09.002
Citations Scopus - 6Web of Science - 7
2014 Charles B, Hardy J, Anderson H, Tapuni A, George R, Norris R, 'Should the dosage of controlled-release oxycodone in advanced cancer be modified on the basis of patient characteristics?', SUPPORTIVE CARE IN CANCER, 22 325-330 (2014)
DOI 10.1007/s00520-013-1973-6
Citations Scopus - 5Web of Science - 4
2014 Bista SR, Lobb M, Haywood A, Hardy J, Tapuni A, Norris R, 'Development, validation and application of an HPLC-MS/MS method for the determination of fentanyl and nor-fentanyl in human plasma and saliva', JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES, 960 27-33 (2014)
DOI 10.1016/j.jchromb.2014.04.019
Citations Scopus - 20Web of Science - 18
2013 Khan SA, George R, Charles BG, Taylor PJ, Heussler HS, Cooper DM, et al., 'Monitoring Salivary Melatonin Concentrations in Children With Sleep Disorders Using Liquid Chromatography-Tandem Mass Spectrometry', THERAPEUTIC DRUG MONITORING, 35 388-395 (2013)
DOI 10.1097/FTD.0b013e3182885cb2
Citations Scopus - 8Web of Science - 7
2013 Ni M, Duley J, George R, Charles B, Shannon C, McGeary R, Norris R, 'Simultaneous determination of thymine and its sequential catabolites dihydrothymine and beta-ureidoisobutyrate in human plasma and urine using liquid chromatography-tandem mass spectrometry with pharmacokinetic application', JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS, 78-79 129-135 (2013)
DOI 10.1016/j.jpba.2013.01.038
Citations Scopus - 7Web of Science - 7
2012 Roberts JA, Norris R, Paterson DL, Martin JH, 'Therapeutic drug monitoring of antimicrobials', BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, 73 27-36 (2012) [C1]
DOI 10.1111/j.1365-2125.2011.04080.x
Citations Scopus - 156Web of Science - 135
Co-authors Jen Martin
2012 Khor KH, Campbell FE, Charles BG, Norris RLG, Greer RM, Rathbone MJ, Mills PC, 'Comparative pharmacokinetics and pharmacodynamics of tablet, suspension and paste formulations of atenolol in cats', JOURNAL OF VETERINARY PHARMACOLOGY AND THERAPEUTICS, 35 437-445 (2012)
DOI 10.1111/j.1365-2885.2011.01342.x
Citations Scopus - 2
2012 Hardy J, Norris R, Anderson H, O'Shea A, Charles B, 'Is saliva a valid substitute for plasma in pharmacokinetic studies of oxycodone and its metabolites in patients with cancer?', SUPPORTIVE CARE IN CANCER, 20 767-772 (2012)
DOI 10.1007/s00520-011-1147-3
Citations Scopus - 16Web of Science - 10
2012 Norris RLG, Paul M, George R, Moore A, Pinkerton R, Haywood A, Charles B, 'A stable-isotope HPLC-MS/MS method to simplify storage of human whole blood samples for glutathione assay', JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES, 898 136-140 (2012)
DOI 10.1016/j.jchromb.2012.04.003
Citations Scopus - 12Web of Science - 13
2011 Barras M, Alraman H, Kirkpatrick CMJ, Harris M, Dakin C, Jess K, et al., 'Bayesian optimisation of tobramycin dosing in paediatric patients with cystic fibrosis', Journal of Pharmacy Practice and Research, 41 183-187 (2011)

Background: In children with cystic fibrosis (CF), tobramycin concentrations are monitored via the area under the plasma concentration time curve (AUC) approach. Currently, a mini... [more]

Background: In children with cystic fibrosis (CF), tobramycin concentrations are monitored via the area under the plasma concentration time curve (AUC) approach. Currently, a minimum of 2 plasma concentrations of tobramycin within one dosing interval are required to estimate the AUC, which is costly, painful and blood collection is often difficult to coordinate. Aim: To evaluate the accuracy of tobramycin AUC estimated using 1 plasma concentration compared to AUC based on 2 plasma concentrations calculated using Bayesian software. Method: Data were collected from paediatric patients with CF prescribed once daily intravenous tobramycin. Each patient had 2 blood samples taken within a dosing interval (according to usual practice at the hospital) on 2 separate occasions during their admission. Data on tobramycin dosing and concentration, and patient demographics from the first occasion were entered into the Bayesian software, TCIWorks, to establish an individual patient's pharmacokinetic model. Data from the second occasion were then also entered into TCIWorks to estimate 2 AUCs - from 1 (AUC1) and 2 (AUC2) plasma concentrations. The accuracy of each patient's AUCs (AUC1 and AUC2) were then evaluated using a Bland-Altman analysis to describe bias relative to the mean of the two values. To show the benefits of good quality data when using TCIWorks, data were obtained and analysed from 2 patient groups. For group A patients, accurate sampling and administration times of the tobramycin infusion were obtained prospectively. Group B consisted of patients from group A plus additional patients who had data collected from a retrospective medical chart review. Results: Data were collected for 30 paediatric patients with CF - 14 in group A and 16 additional patients in group B. In group A, there was no significant bias relative to the mean of the values for AUC1 and AUC2 (mean bias 1; 95%CI -4.9-6.9). A similar result was seen in group B (mean bias -0.7; 95%CI - 10-8.6) indicating that the 2 estimates of tobramycin AUC (using 1 and 2 blood samples) are not significantly different. Conclusion: Once an individual paediatric patient's tobramycin pharmacokinetic model is determined with two blood samples using TCIWorks, only one blood sample is required to estimate an AUC for tobramycin.

DOI 10.1002/j.2055-2335.2011.tb00857.x
Citations Scopus - 4
2011 Khan SA, Neussler H, McGuire T, Dakin C, Pache D, Norris R, et al., 'Therapeutic Options in the Management of Sleep Disorders in Visually Impaired Children: A Systematic Review', CLINICAL THERAPEUTICS, 33 168-181 (2011)
DOI 10.1016/j.clinthera.2011.03.002
Citations Scopus - 8Web of Science - 5
2011 Hardy J, O'Shea A, Gilbert C, Norris R, 'Is levomepromazine stable over time?', PALLIATIVE MEDICINE, 25 284-285 (2011)
DOI 10.1177/0269216310387963
2011 Khan S, Heussler H, McGuire T, Dakin C, Pache D, Cooper D, et al., 'Melatonin for non-respiratory sleep disorders in visually impaired children', COCHRANE DATABASE OF SYSTEMATIC REVIEWS, (2011)
DOI 10.1002/14651858.CD008473.pub2
Citations Scopus - 5Web of Science - 2
2011 Moore AS, Norris R, Price G, Thu N, Ni M, George R, et al., 'Vincristine pharmacodynamics and pharmacogenetics in children with cancer: A limited-sampling, population modelling approach', JOURNAL OF PAEDIATRICS AND CHILD HEALTH, 47 875-882 (2011)
DOI 10.1111/j.1440-1754.2011.02103.x
Citations Scopus - 31Web of Science - 29
2010 Martin JH, Norris R, Barras M, Roberts J, Morris R, Doogue M, Jones GRD, 'Therapeutic monitoring of vancomycin in adult patients: a consensus review of the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, and the Society Of Infectious Diseases Pharmacists.', The Clinical biochemist. Reviews, 31 21-24 (2010)
Co-authors Jen Martin
2010 Norris RL, Martin JH, Thompson E, Ray JE, Fullinfaw RO, Joyce D, et al., 'Current Status of Therapeutic Drug Monitoring in Australia and New Zealand: A Need for Improved Assay Evaluation, Best Practice Guidelines, and Professional Development', THERAPEUTIC DRUG MONITORING, 32 615-623 (2010)
DOI 10.1097/FTD.0b013e3181ea3e8a
Citations Scopus - 24Web of Science - 19
Co-authors Jen Martin
2009 Haywood A, Burrell A, Van Breda K, George R, Testa C, Norris R, 'Stability of melatonin in an extemporaneously compounded sublingual solution and hard gelatin capsule', International Journal of Pharmaceutical Compounding, 13 170-174 (2009)

This study examined the stability of melatonin in a 10-mg/mL oral sublingual solution stored at 4°C or 25°C and in 3-mg capsules stored at ambient (25°C; 60% relative humidity) an... [more]

This study examined the stability of melatonin in a 10-mg/mL oral sublingual solution stored at 4°C or 25°C and in 3-mg capsules stored at ambient (25°C; 60% relative humidity) and accelerated (40°C; 75% relative humidity) conditions over a period of 90 days. A sublingual solution of melatonin 10 mg/mL was prepared with glycerin, ethyl alcohol, stevia powder extract, and tutti-frutti flavor. Six identical solutions were prepared and stored in prescription amber glass bottles at 4°C or 25°C. Triplicate 1-mL samples from each of the six solutions were assayed immediately after preparation and after 7, 14, 28, 60, and 90 days with a stability-indicating high-performance liquid chromatographic method. Six batches of 100 melatonin 3-mg capsules were prepared with Methocel E4M and lactose anhydrous and stored in prescription amber glass bottles at ambient or accelerated conditions. A sample of 10 capsules from each batch was assayed immediately after preparation, and additional samples from each storage condition were assayed at 7, 14, 28, 60, and 90 days. The mean concentration of melatonin exceeded 98% of the initial concentration throughout the 90-day study period for the sublingual solution and capsules under all storage conditions. There were no detectable changes in color, odor, taste, or pH, and no visible microbial growth in any of the sublingual solution samples. Compendia requirements for content uniformity were met for the extemporaneously prepared capsules. Melatonin in an extemporaneously compounded sublingual solution (10 mg/mL) was stable for at least 90 days when stored in prescription amber glass bottles at 4°C or 25°C. Melatonin in extemporaneously prepared capsules (3 mg) was stable for at least 90 days when stored in prescription amber glass bottles at ambient or accelerated conditions.

Citations Scopus - 2
2009 Jones T, Van Breda K, Charles B, Dean AJ, McDermott BM, Norris R, 'Determination of risperidone and 9-Hydroxyrisperidone using HPLC, in plasma of children and adolescents with emotional and behavioural disorders', BIOMEDICAL CHROMATOGRAPHY, 23 929-934 (2009)
DOI 10.1002/bmc.1204
Citations Scopus - 14Web of Science - 11
2008 Hennig S, Norris R, Kirkpatrick CMJ, 'Target concentration intervention is needed for tobramycin dosing in paediatric patients with cystic fibrosis - a population pharmacokinetic study', BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, 65 502-510 (2008)
DOI 10.1111/j.1365-2125.2007.03045.x
Citations Scopus - 38Web of Science - 35
2008 Norris R, 'Surface contamination from cytotoxic drugs', Journal of Pharmacy Practice and Research, 38 332 (2008)
2006 Charles B, Norris R, Xiao X, Hague W, 'Population pharmacokinetics of metformin in late pregnancy', Therapeutic Drug Monitoring, 28 67-72 (2006)

The pharmacokinetic disposition of metformin in late pregnancy was studied together with the level of fetal exposure at birth. Blood samples were obtained in the third trimester o... [more]

The pharmacokinetic disposition of metformin in late pregnancy was studied together with the level of fetal exposure at birth. Blood samples were obtained in the third trimester of pregnancy from women with gestational diabetes or type 2 diabetes; 5 had a previous diagnosis of polycystic ovary syndrome. A cord blood sample also was obtained at the delivery of some of these women, and also at delivery of others who had been taking metformin during pregnancy but from whom no blood had been taken. Plasma metformin concentrations were assayed by a new, validated, reverse-phase HPLC method. A 2-compartment, extravascular maternal model with transplacental partitioning of drug to a fetal compartment was fitted to the data. Nonlinear mixed-effects modeling was performed in NONMEM using FOCE with INTERACTION. Variability was estimated using logarithmic interindividual and additive residual variance models; the covariance between clearance and volume was modeled simultaneously. Mean (range) metformin concentrations in cord plasma and in maternal plasma were 0.81 (range, 0.1-2.6) mg/L and 1.2 (range, 0.1-2.9) mg/L, respectively. Typical population values (interindividual variability, CV%) for allometrically scaled maternal clearance and volume of distribution were 28 L/h/70 kg (17.1%) and 190 L/70 kg (46.3%), giving a derived population-wide half-life of 5.1 hours. The placental partition coefficient for metformin was 1.07 (36.3%). Neither maternal age nor weight significantly influenced the pharmacokinetics. The variability (SD) of observed concentrations about model-predicted concentrations was 0.32 mg/L. The pharmacokinetics were similar to those in nonpregnant patients and, therefore, no dosage adjustment is warranted. Metformin readily crosses the placenta, exposing the fetus to concentrations approaching those in the maternal circulation. The sequelae to such exposure, eg, effects on neonatal obesity and insulin resistance, remain unknown. Copyright © 2006 by Lippincott Williams & Wilkins.

DOI 10.1097/01.ftd.0000184161.52573.0e
Citations Scopus - 98
2006 Anh AVQ, Norris RLG, Charles BG, 'Modelling drug loss during intravenous infusion to premature neonates', Journal of Pharmacy Practice and Research, 36 262-265 (2006)

Background: Our experience has suggested that not all the drug dose put into an IV infusion reached the bloodstream of neonates. Aim: To use sparse-data modelling to estimate how ... [more]

Background: Our experience has suggested that not all the drug dose put into an IV infusion reached the bloodstream of neonates. Aim: To use sparse-data modelling to estimate how much of a continuously infused dose of caffeine, gentamicin, phenobarbitone and vancomycin was delivered. To use the results to develop a modified infusion protocol to minimise drug losses. Method: Various drug infusions were prepared in duplicate (test, control). The test set was delivered through an in vitro infusion system identical to that used in the neonatal intensive care nursery. Samples were collected after flushing the system twice with 1.5 mL of normal saline. Each experiment was replicated 4 times for each drug. Drug concentrations were measured by enzyme immunoassay. Recovery and variability during flushing was described as a function of the normal saline flushing volume using an asymptotic mono-exponential accumulation model. Results: 53% of phenobarbitone, 60% of caffeine, 92% of gentamicin, and 99% of vancomycin doses were recovered. There was considerable variability in the recovery of phenobarbitone. Conclusion: Current infusion protocols appear inadequate for delivery of drugs to neonates and may result in suboptimal therapy. It is recommended that the administration set be completely primed with the drug and any additional volume of normal saline required, then flushed with a further 2 mL of normal saline to obtain a minimum 90% recovery of these drugs.

DOI 10.1002/j.2055-2335.2006.tb00626.x
Citations Scopus - 2
2006 Al Za'abi MA, Dehghanzadeh GH, Norris RLG, Charles BG, 'A rapid and sensitive microscale HPLC method for the determination of indomethacin in plasma of premature neonates with patent ductus arteriousus', JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES, 830 364-367 (2006)
DOI 10.1016/j.jchromb.2005.11.025
Citations Scopus - 28Web of Science - 22
2005 Gilbert CM, McGeary RP, Filippich LJ, Norris RLG, Charles BG, 'Simultaneous liquid chromatographic determination of doxorubicin and its major metabolite doxorubicinol in parrot plasma', JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES, 826 273-276 (2005)
DOI 10.1016/j.jchromb.2005.08.017
Citations Scopus - 24Web of Science - 23
2002 Norris RLG, Seawright AA, Shaw GR, Senogles P, Eaglesham GK, Smith MJ, et al., 'Hepatic xenobiotic metabolism of cylindrospermopsin in vivo in the mouse', Toxicon, 40 471-476 (2002)

Cylindrospermopsin (CYN) is a hepatotoxin isolated from the blue-green alga Cylindrospermopsis raciborskii. The role of both glutathione (GSH) and the cytochrome P450 enzyme syste... [more]

Cylindrospermopsin (CYN) is a hepatotoxin isolated from the blue-green alga Cylindrospermopsis raciborskii. The role of both glutathione (GSH) and the cytochrome P450 enzyme system (P450) in the mechanism of toxicity of CYN has been previously investigated in in vitro systems. We have investigated the role of GSH and P450 in vivo in mice. Mice pre-treated with buthionine sulphoximine and diethyl maleate to deplete hepatic GSH prior to dosing with 0.2 mg/kg CYN showed a seven-day survival rate of 5/13 while the control group rate was 9/14. Dosing mice with 0.2 mg/kg CYN produced a small decrease in hepatic GSH with a characteristic rebound effect at 24 h. The magnitude of this effect is however small and combined with the non-significant difference in survival rates after GSH depletion suggest depletion of GSH by CYN could not be a primary mechanism for CYN toxicity. Conversely, pre-treatment with piperonyl butoxide, a P450 inhibitor, protected mice against CYN toxicity giving a survival rate of 10/10 compared with 4/10 in the control group (p <0.05 Chi squared) and was protective at doses up to 0.8 mg/kg, suggesting activation of CYN by P450 is of primary importance in the mechanism of action. © 2002 Elsevier Science Ltd. All rigths reserved.

DOI 10.1016/S0041-0101(01)00243-4
Citations Scopus - 75
2001 Norris RL, Eaglesham GK, Shaw GR, Smith MJ, Chiswell RK, Seawright AA, Moore MR, 'A sensitive and specific assay for glutathione with potential application to glutathione disulphide, using high-performance liquid chromatography-tandem mass spectrometry', Journal of Chromatography B: Biomedical Sciences and Applications, 762 17-23 (2001)

We have utilised the combination of sensitivity and specificity afforded by coupling high-performance liquid chromatography (HPLC) to a tandem mass spectrometer (MS-MS) to produce... [more]

We have utilised the combination of sensitivity and specificity afforded by coupling high-performance liquid chromatography (HPLC) to a tandem mass spectrometer (MS-MS) to produce an assay which is suitable for assaying glutathione (GSH) concentrations in liver tissue. The sensitivity suggests it may also be suitable for extrahepatic tissues. The method has been validated for GSH using mouse liver samples and also allows the assay of GSSG. The stability of GSH under conditions relevant to the assay has been determined. A 20-µl amount of a diluted methanol extract of tissue is injected with detection limits of 0.2 pmol for GSH and 2 pmol for GSSG. The HPLC uses an Altima C18 (150×4.6 mm, 5 µm) column at 35°C. Chromatography utilises a linear gradient from 0 to 10% methanol in 0.1% formic acid over 5 min, with a final isocratic stage holding at 10% methanol for 5 min. Total flow rate is 0.8 ml/min. The transition from the M+H ion (308.1 m/z for GSH, and 613.3 m/z for GSSG) to the 162.0 m/z (GSH) and 355.3 m/z (GSSG) fragments are monitored. © 2001 Elsevier Science B.V. All rights reserved.

DOI 10.1016/S0378-4347(01)00304-8
Citations Scopus - 48
2001 Norris RLG, Seawright AA, Shaw GR, Smith MJ, Chiswell RK, Moore MR, 'Distribution of

Radiolabelled 14C cylindrospermopsin (CYN) has been prepared and used to investigate the distribution and excretion of CYN in vivo in male Quackenbush mice. At a dose of 0.2 mg/kg... [more]

Radiolabelled 14C cylindrospermopsin (CYN) has been prepared and used to investigate the distribution and excretion of CYN in vivo in male Quackenbush mice. At a dose of 0.2 mg/kg (i.e., approx. median lethal dose) the following mean (SD) urinary and faecal recoveries (cumulative) were obtained, respectively: (0-6 hours, n = 4) 48.2 (29.3)%, 11.9 (21.4)%; (0-12 hours, n = 12) 66.0 (27.1)%, 5.7 (5.6)%; (0-24 hours, n = 12) 68.4 (26.7)%, 8.5 (8.1)%. Mean (SD) recoveries from livers at 6 hours were 20.6 (6.4)% (n = 4), at 48 hours 13.1 (7.7)% (n = 8), and 5-7 days were 2.1 (2.1)% (n = 8). A substantial amount (up to 23%) can be retained in the liver for up to 48 hours with a lesser amount retained in the kidneys. The excretion patterns show substantial interindividual variability between predominantly faecal or urinary excretion, but these patterns are not related in any simple manner to the outcome in terms of toxicity. There is at least one methanol-extractable metabolite as well as a nonmethanol-extractable metabolite in the liver. The methanol-extractable metabolite was not found in the kidney and is more hydrophilic than CYN itself on reverse phase. © 2001 by John Wiley & Sons, Inc.

DOI 10.1002/tox.10008
Citations Scopus - 45
2001 Norris RLG, Eaglesham GK, Shaw GR, Senogles P, Chiswell RK, Smith MJ, et al., 'Extraction and purification of the zwitterions cylindrospermopsin and deoxycylindrospermopsin from Cylindrospermopsis raciborskii', Environmental Toxicology, 16 391-396 (2001)

The hepatotoxin cylindrospermopsin (CYN) has been isolated from the cyanobacterium Cylindrospermopsis raciborskii (C. raci.). Efforts to study this toxin have been hampered by the... [more]

The hepatotoxin cylindrospermopsin (CYN) has been isolated from the cyanobacterium Cylindrospermopsis raciborskii (C. raci.). Efforts to study this toxin have been hampered by the time-consuming requirement to extract it from cultures of the organism. It is usually extracted from lyophilized cells collected from a laboratory culture. Our preliminary work suggested far more of the toxin is available in solution in the culture media than in the cells collected. We have therefore investigated the use of commercially available solid phase extraction sorbents to extract CYN from culture media in which C. raci. has been grown. A range of reverse phase and ion-exchange sorbents were tested across a range of pHs for their ability to retain CYN without success. Subsequently, graphitized carbon cartridges were found to retain CYN strongly. Elution with 5% formic acid in methanol allowed the CYN to be regained for final purification by HPLC. Deoxy-CYN, an analog of CYN can also be extracted using this procedure. © 2001 John Wiley & Sons, Inc.

DOI 10.1002/tox.1048
Citations Scopus - 43
2000 Senogles P, Shaw G, Smith M, Norris R, Chiswell R, Mueller J, et al., 'Degradation of the cyanobacterial toxin cylindrospermopsin, from Cylindrospermopsis raciborskii, by chlorination', Toxicon, 38 1203-1213 (2000)

Cylindrospermopsin, a potent cyanobacterial toxin produced by Cylindrospermopsis raciborskii and other cyanobacteria, is regularly found in water supplies of Queensland, Australia... [more]

Cylindrospermopsin, a potent cyanobacterial toxin produced by Cylindrospermopsis raciborskii and other cyanobacteria, is regularly found in water supplies of Queensland, Australia. This study focussed on the effectiveness of chlorination as a water treatment procedure for cylindrospermopsin degradation. The results demonstrate that relatively low chlorine doses (<1 mg l-1) are sufficient for degradation of cylindrospermopsin, when the dissolved organic carbon content is low. However, if organic matter other than cylindrospermopsin is present in the solution, the effectiveness of chlorine for cylindrospermopsin degradation is reduced as other organic matter present consumes chlorine. Under the experimental conditions using samples with a solution pH of 6-9, a residual chlorine concentration of 0.5 mg l-1 was sufficient to degrade >99% of cylindrospermopsin. Toxin degradation via chlorination occurs within the first minute and no difference was observable between degradation in an open system and in a closed system. With a decrease of the pH from 6 to 4 a reduction in the efficiency of chlorine for degradation of cylindrospermopsin was observable, a possible indication that cylindrospermopsin is more stable to chlorine degradation at lower pH. However, in normal water treatment this is not relevant since the pH is consistently higher than 6.© 2000 Elsevier Science Ltd.

DOI 10.1016/S0041-0101(99)00210-X
Citations Scopus - 48
1999 Seawright AA, Nolan CC, Shaw GR, Chiswell RK, Norris RL, Moore MR, Smith MJ, 'The oral toxicity for mice of the tropical cyanobacterium Cylindrospermopsis raciborskii (Woloszynska)', Environmental Toxicology, 14 135-142 (1999)

Exposure of humans and domestic animals to Cylindrospermopsis raciborskii and its associated toxin cylindrospermopsin in their drinking water will normally be by ingestion. Studie... [more]

Exposure of humans and domestic animals to Cylindrospermopsis raciborskii and its associated toxin cylindrospermopsin in their drinking water will normally be by ingestion. Studies of the cyanobacterium to date have involved dosing mice by the intraperitoneal route, which excludes the possible influence on its toxicity of the alimentary tract barrier. In the present study, outbred MF1 male mice were fasted overnight and then given a single oral dose suspended in normal saline of freeze-dried C. raciborskii culture containing 0.2% cylindrospermopsin. The median lethal dose was in the range 4.4-6.9 mg/kg alkaloid equivalent. Death occurred from 2 to 6 days after dosing, and pathological changes included marked fatty liver, often with periacinar coagulative necrosis, acute renal tubular necrosis, atrophy of the thymic cortex and the lymphoid follicles in the spleen, subepicardial and myocardial hemorrhages, and multiple ulcerations of the esophageal part of the gastric mucosa. The syndrome was consistent with that already reported for cylindrospermopsin dosed parenterally.

DOI 10.1002/(SICI)1522-7278(199902)14:1&lt;135::AID-TOX17&gt;3.0.CO;2-L
Citations Scopus - 107
1999 Norris RL, Eaglesham GK, Pierens G, Shaw GR, Smith MJ, Chiswell RK, et al., 'Deoxycylindrospermopsin, an analog of cylindrospermopsin from cylindrospermopsis raciborskii', Environmental Toxicology, 14 163-165 (1999)

Cylindrospermopsin (CYN) is a hepatotoxic alkaloid found in the blue-green alga Cylindrospermopsis raciborskii (C. raciborskii). Data indicating CYN alone does not account for the... [more]

Cylindrospermopsin (CYN) is a hepatotoxic alkaloid found in the blue-green alga Cylindrospermopsis raciborskii (C. raciborskii). Data indicating CYN alone does not account for the toxicity of freeze dried cultures of C. raciborskii have been presented recently. In an attempt to explain these data, we have purified and characterized the structure of an analog of CYN, deoxycylindrospermopsin (deoxy-CYN). Three mice dosed intraperitoneally (IF) with 0.8 mg/kg of deoxy-CYN showed no toxicity after 5 days. Comparison with the toxicity of CYN (5 day median lethal dose approximately 0.2 mg/kg IF) and its relative abundance in C. raciborskii suggest deoxy-CYN does not contribute significantly to the toxicity of C. raciborskii. The additional toxicity of freeze dried C. raciborskii over pure CYN, therefore, remains unexplained.

DOI 10.1002/(SICI)1522-7278(199902)14:1&lt;163::AID-TOX21&gt;3.0.CO;2-V
Citations Scopus - 154
1999 Eaglesham GK, Norris RL, Shaw GR, Smith MJ, Chiswell RK, Davis BC, et al., 'Use of HPLC-MS/MS to monitor cylindrospermopsin, a blue-green algal toxin, for public health purposes', Environmental Toxicology, 14 151-154 (1999)

Increasing reports of blooms of the blue-green alga Cylindrospermopsis raciborskii (C. raciborskii), which contains the hepatotoxic alkaloid cylindrospermopsin (CYN), have led to ... [more]

Increasing reports of blooms of the blue-green alga Cylindrospermopsis raciborskii (C. raciborskii), which contains the hepatotoxic alkaloid cylindrospermopsin (CYN), have led to public health concerns in Australia. The toxicology of CYN appears complex and is still being elucidated. We have utilized the combination of sensitivity and specificity afforded by coupling high performance liquid chromatography (HPLC) to a tandem mass spectrometer (MS/MS) to produce an assay which is suitable for monitoring low CYN concentrations in water samples. Intact algal cells in the water sample are lysed by a freeze-thaw cycle. After filtration (0.45 µm filter), 110 µL is injected. The HPLC uses an Altima C18 (250 x 4.6 mm, 5 µm) column at 40°C. Chromatography utilizes a linear gradient from 1 to 60% methanol over 5 min, with a final isocratic stage holding at 60% methanol for 1 min. The mobile phase is buffered to 5 mM with ammonium acetate. The transition from the M + H ion (416 m/z) to the 194 m/z fragment is monitored. Linearity of this assay is 1-600 µg/L [peak area= 304 x CYN (µg/L) - 569; r2 = 1.000 (n = 7)]. Using a single point standard curve, total coefficients of variation were 26.4, 10.5, 12.6, and 10.7% at 0.78, 5.2, 104, and 1040 µg/L. This assay is utilized in conjunction with algal cell counts and mouse bioassays to monitor water bodies for public health purposes. The rationale used in employing these methods is discussed.

DOI 10.1002/(SICI)1522-7278(199902)14:1&lt;151::AID-TOX19&gt;3.0.CO;2-D
Citations Scopus - 130
1999 Shaw GR, Sukenik A, Livne A, Chiswell RK, Smith MJ, Seawright AA, et al., 'Blooms of the cylindrospermopsin containing cyanobacterium, Aphanizomenon ovalisporum (Fofti), in newly constructed lakes, Queensland, Australia', Environmental Toxicology, 14 167-177 (1999)

The cyanobacterium, Aphanizomenon ovalisporum (Forti) is reported herein for the first time in Australia. Its distribution appears to be restricted to an isolated subtropical regi... [more]

The cyanobacterium, Aphanizomenon ovalisporum (Forti) is reported herein for the first time in Australia. Its distribution appears to be restricted to an isolated subtropical region which has distinctive water quality parameters including ready availability of nutrients and relatively high chloride and hardness levels. Blooms of A. ovalisporum in Queensland, Australia, formed a thick brown surface scum from spring to autumn in newly constructed shallow lakes. During such blooms, the water and cellular material were both found to contain cylindrospermopsin, a water soluble toxin that produced fatty livers with hepatocyte necrosis in mice similar to the toxicity produced by Cylindrospermopsis raciborskii (Wolosz.). Toxin levels in freeze-dried A. ovalisporum are approximately 25% of those present in freeze-dried C. raciborskii. However, A. ovalisporum appears to release more of the produced toxin into the water body than does C. raciborskii. Sequencing of the 16s ribosomal RNA gene of A. ovalisporum isolated from the Australian bloom showed that it was virtually identical to A. ovalisporum isolated from Lake Kinneret. Much lower homology was found between A. ovalisporum and other species of that genus (i.e., A. flos-aquae and A. gracile) or C. raciborskii, which is known to produce the toxin cylindrospermopsin.

DOI 10.1002/(SICI)1522-7278(199902)14:1&lt;167::AID-TOX22&gt;3.0.CO;2-O
Citations Scopus - 158
1997 Salm P, Taylor PJ, Clark A, Balderson GA, Grygotis A, Norris RLG, et al., 'High-performance liquid chromatography tandem mass spectrometry as a reference for analysis of tacrolimus to assess two immunoassays in patients with liver and renal transplants', THERAPEUTIC DRUG MONITORING, 19 694-700 (1997)
DOI 10.1097/00007691-199712000-00015
Citations Scopus - 22Web of Science - 21
1996 Taylor PJ, Jones A, Balderson GA, Lynch SV, Norris RLG, Pond SM, 'Sensitive, specific quantitative analysis of tacrolimus (FK506) in blood by liquid chromatography electrospray tandem mass spectrometry', CLINICAL CHEMISTRY, 42 279-285 (1996)
Citations Scopus - 91Web of Science - 88
1995 DODDS HM, NORRIS RLG, JOHNSON AG, POND SM, 'EVALUATION AND COMPARISON OF THE TDXII, STRATUS, AND OPUS DIGOXIN ASSAYS', THERAPEUTIC DRUG MONITORING, 17 68-74 (1995)
DOI 10.1097/00007691-199502000-00011
Citations Scopus - 15Web of Science - 14
1994 TAYLOR PJ, SALM P, NORRIS RLG, RAVENSCROFT PJ, POND SM, 'COMPARISON OF HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND MONOCLONAL FLUORESCENCE POLARIZATION IMMUNOASSAY FOR THE DETERMINATION OF WHOLE-BLOOD CYCLOSPORINE-A IN LIVER AND HEART-TRANSPLANT PATIENTS', THERAPEUTIC DRUG MONITORING, 16 526-530 (1994)
DOI 10.1097/00007691-199410000-00015
Citations Scopus - 16Web of Science - 14
1994 NORRIS RLG, RAVENSCROFT PJ, POND SM, 'SENSITIVE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY WITH ULTRAVIOLET DETECTION OF METHADONE ENANTIOMERS IN PLASMA', JOURNAL OF CHROMATOGRAPHY B-BIOMEDICAL APPLICATIONS, 661 346-350 (1994)
DOI 10.1016/0378-4347(94)00341-6
Citations Scopus - 37Web of Science - 35
1993 SALM P, NORRIS RLG, TAYLOR PJ, DAVIS DE, RAVENSCROFT PJ, 'A RELIABLE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ASSAY FOR HIGH-THROUGHPUT ROUTINE CYCLOSPORINE-A MONITORING IN WHOLE-BLOOD', THERAPEUTIC DRUG MONITORING, 15 65-69 (1993)
DOI 10.1097/00007691-199302000-00012
Citations Scopus - 25Web of Science - 21
1992 Taylor PJ, Charles BG, Norris R, Salm P, Ravenscroft PJ, 'Measurement of dothiepin and its major metabolites in plasma by high-performance liquid chromatography', Journal of Chromatography B: Biomedical Sciences and Applications, 581 152-155 (1992)

This paper describes a reversed-phase high-performance liquid chromatographic method which will simultaneously measure dothiepin and its three major metabolites (northiaden, north... [more]

This paper describes a reversed-phase high-performance liquid chromatographic method which will simultaneously measure dothiepin and its three major metabolites (northiaden, northiaden-S-oxide and dothiepin-S-oxide) in plasma using trimipramine as internal standard. Sample preparation involved a basic extraction using diethyl ether followed by an acid back-extraction. The method we report is linear over the range 50-1000 ng/ml (r = 0.999), for all analytes. Total imprecision is less than 11% (coefficient of variation) and accuracy is greater than 94% (n = 20). Recovery of analytes varied considerably from 51.7% for northiaden-S-oxide to 90.2% for dothiepin-S-oxide. © 1992.

DOI 10.1016/0378-4347(92)80460-8
Citations Scopus - 9
1992 Chen Y, Norris RL, Schneider JJ, Ravenscroft PJ, 'The influence of vancomycin concentration and pH of plasma on vancomycin protein binding', J. Pharm. Toxicol. Method, 28(1) 57-60 (1992) [C1]
Citations Scopus - 8Web of Science - 6
Co-authors Jennifer Schneider
1989 Norris RL, Taylor PJ, Schneider JJ, Ravenscroft PJ, Charles BG, 'Sensitive measurement of oxazepam in plasma by high performance liquid chromatography', J. Drug Dev., 2(2) 109-113 (1989) [C1]
Citations Scopus - 1
Co-authors Jennifer Schneider
1988 CHARLES BG, NORRIS RLG, RAVENSCROFT PJ, 'A MODIFIED ASSAY FOR CYCLOSPORIN IN BLOOD USING SOLID-PHASE EXTRACTION WITH HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY', THERAPEUTIC DRUG MONITORING, 10 97-100 (1988)
DOI 10.1097/00007691-198810010-00017
Citations Scopus - 14Web of Science - 13
1987 CHARLES BG, SCHNEIDER JJ, NORRIS RLG, RAVENSCROFT PJ, 'TEMELASTINE DOES NOT AFFECT THEOPHYLLINE PHARMACOKINETICS IN NORMAL SUBJECTS', BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, 24 673-675 (1987)
DOI 10.1111/j.1365-2125.1987.tb03229.x
Citations Scopus - 3Web of Science - 4
Co-authors Jennifer Schneider
1986 NORRIS RLG, THOMAS MJ, CRASWELL PW, 'ASSESSMENT OF A 2-STEP HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY USING DUAL-WAVELENGTH ULTRAVIOLET MONITORING FOR 25-HYDROXYERGOCALCIFEROL AND 25-HYDROXYCHOLECALCIFEROL IN HUMAN-SERUM OR PLASMA', JOURNAL OF CHROMATOGRAPHY, 381 53-61 (1986)
DOI 10.1016/S0378-4347(00)83564-1
Citations Scopus - 21Web of Science - 13
1984 Cameron J, Stafford W, Pritchard D, Norris R, Ravenscroft P, 'Intravenous disopyramide in acute myocardial infarction: A haemodynamic and pharmacokinetic study', Journal of Cardiovascular Pharmacology, 6 126-131 (1984)

We studied the haemodynamic and pharmacokinetic effects of intravenous disopyramide phosphate in 12 patients (average age, 59 years) with proven trans-mural myocardial infarction,... [more]

We studied the haemodynamic and pharmacokinetic effects of intravenous disopyramide phosphate in 12 patients (average age, 59 years) with proven trans-mural myocardial infarction, whose symptoms began less than 12 h prior to the study. The aim was to assess the effects of intravenous disopyramide (2 mg/kg given over 5 min) on cardiac index (CI), left ventricular filling pressure (LVFP), heart rate (HR), mean systemic arterial blood pressure (BP), and systemic vascular resistance (SVR) for 60 min after administration of the drug. Both total and free concentrations of disopyramide in the plasma were also measured. A significant elevation (p &#60; 0.01) of LVFP (estimated indirectly as pulmonary artery end-diastolic pressure) occurred and persisted through the 1-h evaluation period. There was a small but significant (p = 0.02) initial fall in CI and a rise in SVR (p = 0.05). No significant changes occurred in HR or BP. Serum concentrations of disopyramide reached recommended therapeutic concentrations. There was no significant correlation of the changes in cardiac variables from pretreatment values with total serum concentrations, but the free concentration of disopyramide in plasma correlated better with cardiac effect, and the relationships of the free concentration of disopyramide to the changes in LVFP and in SVR from pretreatment values were significant (p &#60; 0.05). In two patients studied in detail, there was evidence of dose-dependent protein binding of disopyramide. © 1984 Raven Press, New York.

Citations Scopus - 7
1984 NORRIS RLG, AHOKAS JT, RAVENSCROFT PJ, HENRY M, 'BINDING OF DISOPYRAMIDE TO ALPHA-1-ACID GLYCOPROTEIN IN PLASMA MEASURED BY COMPETITIVE-EQUILIBRIUM DIALYSIS', JOURNAL OF PHARMACEUTICAL SCIENCES, 73 824-826 (1984)
DOI 10.1002/jps.2600730630
Citations Scopus - 16Web of Science - 20
1984 Dowell PS, Pierce DM, Franklin RA, Norris R, Harries H, Whiteland H, 'The pharmacokinetics of fentiazac and its metabolite, p-hydroxyfentiazac, after twice-daily oral administration to Male volunteers', Xenobiotica, 14 947-953 (1984)

1. The pharmacokinetics of the anti-inflammatory agent fentiazac and its principal plasma metabolite, p-hydroxyfentiazac, have been investigated after repeated oral administration... [more]

1. The pharmacokinetics of the anti-inflammatory agent fentiazac and its principal plasma metabolite, p-hydroxyfentiazac, have been investigated after repeated oral administration of fentiazac to male volunteers. Each volunteer received 200 mg of fentiazac twice daily for 15 d. 2. Absorption was quite rapid, though some inter-subject variation in rates of absorption and bioavailability was observed. tmax values after the first dose ranged from 0.75.3 h while CPmax values were 1050-4880 ng/ml. 3. Elimination of fentiazac from plasma occurred rapidly in curvilinear fashion, so that concentrations were only 1% of their maximum value by 12 h after dosing. 4. Maximum concentrations of p-hydroxyfentiazac after a single dose of fentiazac were 25.6-79.4% of those of fentiazac and were achieved at similar times. The metabolite was more slowly eliminated; the mean concentration of p-hydroxyfentiazac 12 h after a single dose was still 8% of its maximal value. 5. On repeated administration, AUC0.12h values for fentiazac and hydroxyfentiazac increased, as indicated by accumulation factors of 1.17 ± 0.11 and 1.30± 0.11 on days 8 and 15, respectively, for fentiazac and 1.72 ± 015 and 1.77 ± 010 for hydroxyfentiazac There was no significant difference between days 8 and 15 in the extent of accumulation of either compound. Trough concentrations of fentiazac and hydroxyfentiazac on days 12 and 15 were similar to those on day 8. The clinical significance of these observations is discussed. © 1984 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.

DOI 10.3109/00498258409151493
Citations Scopus - 2
1983 HOLT GW, NORRIS RLG, RAVENSCROFT PJ, BETT JHN, DRYBURGH LG, BOYLE CM, 'EFFECT OF DISOPYRAMIDE ON LEFT-VENTRICULAR PERFORMANCE - THE RELATIONSHIP OF FREE AND TOTAL CONCENTRATIONS OF THE DRUG AND OF ITS MONO-N-DEALKYLATED METABOLITE TO NON-INVASIVE INDEXES OF FUNCTION', JOURNAL OF CARDIOVASCULAR PHARMACOLOGY, 5 51-54 (1983)
DOI 10.1097/00005344-198301000-00007
Citations Scopus - 10Web of Science - 18
1982 NORRIS RLG, AHOKAS JT, RAVENSCROFT PJ, 'DETERMINATION OF UN-BOUND FRACTION OF DISOPYRAMIDE IN PLASMA - A COMPARISON OF EQUILIBRIUM DIALYSIS, ULTRAFILTRATION THROUGH DIALYSIS MEMBRANES AND ULTRAFREE ANTICONVULSANT DRUG FILTERS', JOURNAL OF PHARMACOLOGICAL METHODS, 7 7-14 (1982)
DOI 10.1016/0160-5402(82)90053-5
Citations Scopus - 11Web of Science - 11
1982 NORRIS RLG, AHOKAS JT, RAVENSCROFT PJ, 'SIMULTANEOUS HPLC ASSAY OF MONO-N-DEALKYLATED DISOPYRAMIDE, QUINIDINE AND DISOPYRAMIDE', CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, 9 452-453 (1982)
Citations Scopus - 2Web of Science - 2
1982 NORRIS RLG, AHOKAS JT, RAVENSCROFT PJ, 'SIMULTANEOUS HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY FOR QUINIDINE, DISOPYRAMIDE AND THE MONO-N-DEALKYLATED METABOLITE OF DISOPYRAMIDE', JOURNAL OF CHROMATOGRAPHY, 230 433-437 (1982)
DOI 10.1016/S0378-4347(00)80495-8
Citations Scopus - 7Web of Science - 11
1981 NORRIS RLG, AHOKAS JT, RAVENSCROFT PJ, 'DETERMINATION OF UN-BOUND FRACTION OF DISOPYRAMIDE IN PLASMA USING A RAPID ULTRAFILTRATION METHOD', CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, 8 657-658 (1981)
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Conference (13 outputs)

Year Citation Altmetrics Link
2018 Radovanovic M, Schneider J, Ackland S, Norris R, Martin J, Galettis P, 'Microsampling as an Alternative CollectionMethod to Venous Blood to Quantify Capecitabine and its Metabolites by LC-MS/MS', ASIA-PACIFIC JOURNAL OF CLINICAL ONCOLOGY (2018)
Co-authors Peter Galettis, Stephen Ackland, Jen Martin, Jennifer Schneider
2016 Manollaras K, Nolan L, Day R, Norris R, Dear R, 'EFFICACY OF SCALP COOLING AND PHARMACOKINETICS AT THE KINGHORN CANCER CENTRE, ST VINCENT'S HOSPITAL', ASIA-PACIFIC JOURNAL OF CLINICAL ONCOLOGY (2016)
2011 Lobb M, Norris RLG, Charles B, Gilshenan K, Moore A, Pinkerton R, 'Blood collection technique for pharmacokinetic studies of doxorubicin in paediatric patients', THERAPEUTIC DRUG MONITORING, Stuttgart, GERMANY (2011)
2011 Ni M, Duley JA, George R, Charles BG, Norris RLG, 'Determination of thymine, dihydrothymine and ureidoisobutyrate in human plasma, saliva and urine using HPLC-tandem mass spectrometry', THERAPEUTIC DRUG MONITORING, Stuttgart, GERMANY (2011)
2011 Khan SA, George R, Taylor P, Charles BG, McGuire T, Heussler H, et al., 'The assay of Melatonin in saliva by high-performance liquid chromatography-tandem mass spectrometry', THERAPEUTIC DRUG MONITORING, Stuttgart, GERMANY (2011)
2011 Norris RLG, Barras M, Alraman H, Kirkpatrick C, Dakin C, Harris M, Jess K, 'Comparison of one vs. two blood samples for determination of tobramycin AUC in children with cystic fibrosis', THERAPEUTIC DRUG MONITORING, Stuttgart, GERMANY (2011)
2009 George R, Charles B, Duley J, Norris R, 'The Assay of Thymine and Dihydrothymine using HPLC-MS/MS in Human Plasma, Saliva and Urine', THERAPEUTIC DRUG MONITORING, Montreal, CANADA (2009)
2009 Van Breda K, Norris R, Pinkerton R, Charles B, 'The Development and Validation of an Assay for Vincristine in Plasma using HPLC-MS/MS', THERAPEUTIC DRUG MONITORING, Montreal, CANADA (2009)
2009 Norris R, Morris R, Thompson E, Ray J, Barras M, Jones G, Martin J, 'A Survey of Therapeutic Drug Monitoring in Australasia', THERAPEUTIC DRUG MONITORING, Montreal, CANADA (2009)
Co-authors Jen Martin
2009 Charles B, George R, Norris R, Shannon C, Cameron A, Musgrave K, Duley J, 'Towards a Prospective Screening Test for Fluoropyrimidine Toxicity: Preliminary Pharmacokinetic Data for Thymine and Dihydrothymine in Healthy Male Adults', THERAPEUTIC DRUG MONITORING, Montreal, CANADA (2009)
2003 Dehghanzadeh GH, Norris RLG, Marnett LJ, Charles BG, 'Raped method for the determination of plasma indomethacin in premature infants by HPLC', THERAPEUTIC DRUG MONITORING, BASEL, SWITZERLAND (2003)
1999 Eaglesham GK, Norris RL, Shaw GR, Smith MJ, Chiswell RK, Davis BC, et al., 'Use of HPLC-MS/MS to monitor cylindrospermopsin, a blue-green algal toxin, for public health purposes', ENVIRONMENTAL TOXICOLOGY, PERTH, AUSTRALIA (1999)
DOI 10.1002/(SICI)1522-7278(199902)14:1&lt;151::AID-TOX19&gt;3.3.CO;2-4
Citations Web of Science - 122
1999 Chiswell RK, Shaw GR, Eaglesham G, Smith MJ, Norris RL, Seawright AA, Moore MR, 'Stability of cylindrospermopsin, the toxin from the cyanobacterium, Cylindrospermopsis raciborskii: Effect of pH, temperature, and sunlight on decomposition', ENVIRONMENTAL TOXICOLOGY, PERTH, AUSTRALIA (1999)
DOI 10.1002/(SICI)1522-7278(199902)14:1&lt;155::AID-TOX20&gt;3.0.CO;2-Z
Citations Scopus - 182Web of Science - 168
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Grants and Funding

Summary

Number of grants 7
Total funding $1,679,373

Click on a grant title below to expand the full details for that specific grant.


20191 grants / $190,000

Early phase high throughput studies of cannabinoids using new understandings of glioblastoma biology, radiobiology and pharmacology$190,000

Funding body: Hunter Medical Research Institute

Funding body Hunter Medical Research Institute
Project Team Professor Jennifer Martin, Doctor Michael Fay, Doctor James Lynam, Doctor Catherine Lucas, Doctor Peter Galettis, Associate Professor Nikola Bowden, Associate Professor Jenny Schneider, Associate Professor Paul Tooney, Doctor Ross Norris, Doctor Moira Graves
Scheme Project Grant
Role Investigator
Funding Start 2019
Funding Finish 2021
GNo G1900511
Type Of Funding C3120 - Aust Philanthropy
Category 3120
UON Y

20141 grants / $664,873

Exploring a mechanism to underpin a novel colonic therapy for colitis$664,873

Funding body: NHMRC (National Health & Medical Research Council)

Funding body NHMRC (National Health & Medical Research Council)
Scheme NHMRC
Role Investigator
Funding Start 2014
Funding Finish 2016
GNo
Type Of Funding C1100 - Aust Competitive - NHMRC
Category 1100
UON N

20121 grants / $150,000

A novel thiopurine to effect faster more tolerated and safe immunosuppression$150,000

Funding body: Gutsy

Funding body Gutsy
Scheme The Gutsy Group
Role Investigator
Funding Start 2012
Funding Finish 2014
GNo
Type Of Funding C1700 - Aust Competitive - Other
Category 1700
UON N

20101 grants / $50,000

Pharmacokinetic pharmacodynamic understanding of for fentanyl intra-nasal for children in pain or during painful procedures$50,000

Funding body: Queensland Emergency Medicine Research Fund

Funding body Queensland Emergency Medicine Research Fund
Scheme Queensland Emergency Medical Research Fund
Role Investigator
Funding Start 2010
Funding Finish 2011
GNo
Type Of Funding C1500 - Aust Competitive - Commonwealth Other
Category 1500
UON N

20091 grants / $218,500

An Oral Loading Test to Predict Susceptibility to Fluoropyrimidine Drug Toxicity$218,500

Funding body: NHMRC (National Health & Medical Research Council)

Funding body NHMRC (National Health & Medical Research Council)
Scheme Project Grant
Role Investigator
Funding Start 2009
Funding Finish 2010
GNo
Type Of Funding C1100 - Aust Competitive - NHMRC
Category 1100
UON N

20071 grants / $156,000

An Oral Screening test to Predict Susceptibility to Pyrimidine Anticancer Drug Toxicity$156,000

Funding body: Queensland Cancer Foundation

Funding body Queensland Cancer Foundation
Scheme Queensland Cancer Foundation
Role Investigator
Funding Start 2007
Funding Finish 2008
GNo
Type Of Funding C2220 - Aust StateTerritoryLocal - Other
Category 2220
UON N

20061 grants / $250,000

Pharmacokinetics, Pharmacodynamics and Pharmacogenomics of Drugs used in the Treatment of Acute Lymphoblastic Leukaemia in Children$250,000

Funding body: Mayne Health

Funding body Mayne Health
Scheme Project Grant
Role Investigator
Funding Start 2006
Funding Finish 2006
GNo
Type Of Funding External
Category EXTE
UON N
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Research Supervision

Number of supervisions

Completed4
Current1

Current Supervision

Commenced Level of Study Research Title Program Supervisor Type
2015 PhD Efficient and Cost Effective Use of HPLC-MS/MS for Drug Assay in support of Therapeutic Drug Monitoring General Medicine, The University of New South Wales Principal Supervisor

Past Supervision

Year Level of Study Research Title Program Supervisor Type
2017 PhD Methadone dosing in pain management. School of Pharmacy, Griffith University Pharmacy, Griffith University Co-Supervisor
2014 PhD Dose individualisation of Phenytoin Pharmacy, Griffith university Co-Supervisor
2014 PhD transitioning chronic pain patients from gabapentin to pregabalin Pharmacy, Griffith University Principal Supervisor
2014 PhD Pharmacokinetics of selected anticonvulsant medications in newborn infants with hypoxic ischaemic encephalopathy undergoing treatment with therapeutic hypothermia. Pharmacy, University of Queensland Co-Supervisor
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Dr Ross Norris

Position

Advisor - Clinical Pharmacology Laboratory
School of Medicine and Public Health
Faculty of Health and Medicine

Contact Details

Email ross.norris@newcastle.edu.au
Phone (02) 49854059

Office

Room 3108
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