Mr Chris Lourens

Research Area: Global Health
Scientific Themes: Tropical Medicine & Global Health

Proficiency testing programme for antimalarial drugs analysed in pharmacology laboratories.

Reference material programme offering small quantities of antimalarial drug compounds to research laboratories in the field of malaria research

There are no collaborations listed for this principal investigator.

Lourens C, Lindegardh N, Barnes KI, Guerin PJ, Sibley CH, White NJ, Tarning J. 2014. Benefits of a pharmacology antimalarial reference standard and proficiency testing program provided by the Worldwide Antimalarial Resistance Network (WWARN). Antimicrob Agents Chemother, 58 (7), pp. 3889-3894. | Show Abstract | Read more

Comprehensive assessment of antimalarial drug resistance should include measurements of antimalarial blood or plasma concentrations in clinical trials and in individual assessments of treatment failure so that true resistance can be differentiated from inadequate drug exposure. Pharmacometric modeling is necessary to assess pharmacokinetic-pharmacodynamic relationships in different populations to optimize dosing. To accomplish both effectively and to allow comparison of data from different laboratories, it is essential that drug concentration measurement is accurate. Proficiency testing (PT) of laboratory procedures is necessary for verification of assay results. Within the Worldwide Antimalarial Resistance Network (WWARN), the goal of the quality assurance/quality control (QA/QC) program is to facilitate and sustain high-quality antimalarial assays. The QA/QC program consists of an international PT program for pharmacology laboratories and a reference material (RM) program for the provision of antimalarial drug standards, metabolites, and internal standards for laboratory use. The RM program currently distributes accurately weighed quantities of antimalarial drug standards, metabolites, and internal standards to 44 pharmacology, in vitro, and drug quality testing laboratories. The pharmacology PT program has sent samples to eight laboratories in four rounds of testing. WWARN technical experts have provided advice for correcting identified problems to improve performance of subsequent analysis and ultimately improved the quality of data. Many participants have demonstrated substantial improvements over subsequent rounds of PT. The WWARN QA/QC program has improved the quality and value of antimalarial drug measurement in laboratories globally. It is a model that has potential to be applied to strengthening laboratories more widely and improving the therapeutics of other infectious diseases.

Lourens C, Watkins WM, Barnes KI, Sibley CH, Guerin PJ, White NJ, Lindegardh N. 2010. Implementation of a reference standard and proficiency testing programme by the World Wide Antimalarial Resistance Network (WWARN). Malar J, 9 (1), pp. 375. | Show Abstract | Read more

BACKGROUND: The Worldwide Antimalarial Resistance Network (WWARN) is a global collaboration to support the objective that anyone affected by malaria receives effective and safe drug treatment. The Pharmacology module aims to inform optimal anti-malarial drug selection. There is an urgent need to define the drug exposure - effect relationship for most anti-malarial drugs. Few anti-malarials have had their therapeutic blood concentration levels defined. One of the main challenges in assessing safety and efficacy data in relation to drug concentrations is the comparability of data generated from different laboratories. To explain differences in anti-malarial pharmacokinetics in studies with different measurement laboratories it is necessary to confirm the accuracy of the assay methods. This requires the establishment of an external quality assurance process to assure results that can be compared. This paper describes this process. METHODS: The pharmacology module of WWARN has established a quality assurance/quality control (QA/QC) programme consisting of two separate components:1. A proficiency testing programme where blank human plasma spiked with certified reference material (CRM) in different concentrations is sent out to participating bioanalytical laboratories.2. A certified reference standard programme where accurately weighed amounts of certified anti-malarial reference standards, metabolites, and internal standards are sent to participating bioanalytical and in vitro laboratories. CONCLUSION: The proficiency testing programme is designed as a cooperative effort to help participating laboratories assess their ability to carry out drug analysis, resolve any potential problem areas and to improve their results - and, in so doing, to improve the quality of anti-malarial pharmacokinetic data published and shared with WWARN.By utilizing the same source of standards for all laboratories, it is possible to minimize bias arising from poor quality reference standards. By providing anti-malarial drug standards from a central point, it is possible to lower the cost of these standards.

DAUTH J, LOURENS C, DREYER MJ, RECHAV Y, FIELDEN LJ, CLARKE FC, MACKIE AJ. 1990. BISALBUMINEMIA IN THE MOUNTAIN TORTOISE GEOCHELONE-PARDALIS SOUTH AFRICAN JOURNAL OF WILDLIFE RESEARCH, 20 (4), pp. 146-147.

RAUBENHEIMER EJ, OKONSKA ET, DAUTH J, DREYER MJ, LOURENS C, BRUWER CA, DEVOS V. 1990. FLUORIDE CONCENTRATIONS IN THE RIVERS OF THE KRUGER NATIONAL-PARK - A 5 YEAR SURVEY SOUTH AFRICAN JOURNAL OF WILDLIFE RESEARCH, 20 (4), pp. 127-129.

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