Iain J. McGilveray

Bioanalytical Method Validation—A Revisit with a Decade of Progress

This report is a synthesis of (1) the earlier conference on Analytical Methods Validation−Bioavailability, Bioequivalence and Pharmacokinetic Studies (Conference held in Arlington, VA, December 3–5, 1990 and the report published in Pharmaceutical Research, 9: 588-592, 1992) and (2) the workshop on “Bioanalytical Methods Validation—A Revisit with a Decade of Progress,” (Workshop held in Arlington, VA, January 12–14, 2000), sponsored by the American Association of Pharmaceutical Scientists and the U. S. Food and Drug Administration. The bioanalytical method validation workshop of January 12–14, 2000 was directed towards small molecules. A separate workshop was held in March 1–3, 2000 to discuss validation principles for macromolecules. The purpose of this report is to represent the progress in analytical methodologies over the last decade and assessment of the major agreements and issues discussed with regard to small molecules at both the conference and the workshop. The report is also intended to provide guiding principles for validation of bioanalytical methods employed in support of bioavailability, bioequivalence, and pharmacokinetic studies in man and in animals.

Analytical methods validation: Bioavailability, bioequivalence and pharmacokinetic studies: Sponsored by the American Association of Pharmaceutical Chemists, U.S. Food and Drug Administration, Fédération Internationale Pharmaceutique, Health Protection Branch (Canada) and Association of Official Analytical Chemists

Abstract This is a summary report of the conference on ‘Analytical Methods Validation: Bioavailability, Bioequivalence and Pharmacokinetic Studies.’ The conference was held from December 3 to 5, 1990, in the Washington, DC area and was sponsored by the American Association of Pharmaceutical Scientists, U.S. Food and Drug Administration, Federation Internationale Pharmaceutique, Health Protection Branch (Canada) and Association of Official Analytical Chemists. The purpose of the report is to represent our assessment of the major agreements and issues discussed at the conference. This report is also intended to provide guiding principles for validation of analytical methods employed in bioavailability, bioequivalence and pharmacokinetic studies in man and animals. The objectives of the conference were: (1) to reach a consensus on what should be required in analytical methods validation and the procedures to establish validation; (2) to determine processes of application of the validation procedures in the bioavailability, bioequivalence and pharmacokinetic studies; and (3) to develop a report on analytical methods validation (which may be referred to in developing future formal guidelines). Acceptable standards for documenting and validating analytical methods with regard to processes, parameters or data treatments were discussed because of their importance in assessment of pharmacokinetic. bioavailability, and bioequivalence studies. Other topics which were considered essential in the conduct of pharmacokinetic studies or in establishing bioequivalency criteria, including measurement of drug metabolites and stereoselectivc determinations, were also deliberated.

Pharmacokinetic and pharmacodynamic interactions between diltiazem and quinidine

To examine the pharmacokinetic and pharmacodynamic interactions between quinidine and diltiazem because both drugs can inhibit drug metabolism.

Quantification of ketoprofen enantiomers in human plasma based on solid-phase extraction and enantioselective column chromatography

An HPLC method for the quantification of ketoprofen enantiomers in human plasma is described. Following extraction with a disposable C18 solid-phase extraction column, separation of ketoprofen enantiomers and I.S. (3,4-dimethoxy benzoic acid) was achieved using a chiral column [Chirex 3005; (R)-1-naphthylglycine 3,5-dinitrobenzoic acid] with the mobile phase, 0.02 M ammonium acetate in methanol, set at a flow-rate of 1.2 ml/min. Baseline separation of ketoprofen enantiomers and I.S., free from interferences, was achieved in less than 20 min. The calibration curves (n = 14) were linear over the concentration range of 0.16 to 5.00 micrograms/ml per enantiomer [mean r2 of 0.999 for both enantiomers, root mean square error were 0.015 for R(-) and 0.013 for S(+)]. The inter-day coefficient of variation for duplicate analysis of spiked samples was less than 7% and the accuracy was more than 93% over the over the concentration range of 0.2 to 4.0 micrograms/ml for individual enantiomer using 1 ml of plasma sample. This method has been applied to a pharmacokinetic study from healthy human volunteers following the administration of a ketoprofen extended release product (200 mg). This method is simple, fast and should find wide application in monitoring pharmacokinetic studies of ketoprofen.

BIO-international 94, conference on bioavailability, bioequivalence and pharmacokinetic studies: Pre-Conference Satellite on in vivo/in vitro correlation Munich, Germany, 14–17 June 1994

Abstract Organized by: International Pharmaceutical Federation (F.I.P.) together with American Association of Pharmaceutical Scientists (AAPS), European Federation of Pharmaceutical Sciences (EUFEPS), U.S. Food and Drug Administration (FDA), and Health Protection Branch, Canada (HPB). Co-sponsored by: Academy of Pharmaceutical Sciences and Technology, Japan (APSTJ), Bundesgesundheitsamt (BGA), Germany, Dutch Medicines Evaluation Board (RIVM), The Netherlands, and Zentrallaboratorium Deutscher Apotheker (ZL), Germany.

Effect of an Acute Dose of Alcohol on the Pharmacokinetics of Oral Nifedipine in Humans

Pharmacokinetic and pharmacodynamic interactions of alcohol and nifedipine were assessed in 10 healthy human volunteers. Doses of 20 mg (2 × 10-mg capsules) of nifedipine were administered with either 150 ml of orange juice or 75 ml of alcohol (94%) in 75 ml of orange juice according to a crossover randomized design. Plasma nifedipine levels were monitored for 16 hr after each dosing, along with pulse rate and blood pressure. The relative bioavailability of nifedipine, measured as AUC, was increased by 54% (533 vs 346 ng · hr/ml) after the dose of alcohol (P < 0.0002). However, there were no significant differences between treatments in Cmax,tmax, or t1/2. Although there was no difference in the systolic and diastolic blood pressure and pulse rate between the two treatment groups, the time to reach peak heart rate was significantly faster in the group treated with alcohol (1.4 vs 2.2 hr). This study shows that ethanol increases the bioavailability of nifedipine and decreases the time for onset of increased heart rate.

Monitoring of blood levels of cyclosporine in renal and cardiac transplant recipients--comparison of HPLC to Incstar CYCLO-Trac SP RIA.

Cyclosporine in whole blood samples from renal and cardiac transplant recipients was measured by high-performance liquid chromatography (HPLC) and by CYCLO-Trac SP specific radioimmunoassay (RIA). The fresh samples assayed by RIA were remeasured in a second laboratory after storage at -20 degrees C for two to six months and good interlaboratory agreement was obtained on the 59 samples assayed (y = 0.926x + 14.8 micrograms/L, r = 0.982). The calibration curve for RIA was not influenced by fresh whole blood, hemolyzed whole blood or serum matrix from normal volunteers. However, comparison of the RIA results from patient samples with those from an HPLC procedure showed that RIA values averaged about double those measured by HPLC. The difference is attributable to differences between the blood matrix of transplant and nontransplant subjects, rather than exclusively to the apparent nonspecific nature of the antibody.

Overview of Workshop: In Vitro Dissolution of Immediate Release Dosage Forms: Development of in Vivo Relevance and Quality Control Issues

Scientists from industry, academia, and the regulatory agencies met to discuss the role of dissolution tests with immediate release dosage forms. Dissolution is clearly important in formulation development and can provide evidence for later use in quality control. Regulatory agencies also need such information in assessing “change” in manufacture to decide when in vivo information would be required. The workshop examined the limitations of dissolution as a surrogate for in vivo testing. As well as calibration and specification issues, a major challenge is to provide tests for highly water insoluble drugs in which formulation is used to enhance bioavailability. General specifications are difficult and case-by-case consideration is often required.