Recommendations for classification of commercial LBA kits for biomarkers in drug development from the GCC for bioanalysis.

Over the last decade, the use of biomarker data has become integral to drug development. Biomarkers are not only utilized for internal decision-making by sponsors; they are increasingly utilized to make critical decisions for drug safety and efficacy. As the regulatory agencies are routinely making decisions based on biomarker data, there has been significant scrutiny on the validation of biomarker methods. Contract research organizations regularly use commercially available immunoassay kits to validate biomarker methods. However, adaptation of such kits in a regulated environment presents significant challenges and was one of the key topics discussed during the 12th Global Contract Research Organization Council for Bioanalysis (GCC) meeting. This White Paper reports the GCC members' opinion on the challenges facing the industry and the GCC recommendations on the classification of commercial kits that can be a win-win for commercial kit vendors and end users.

Comparative study on the bioequivalence of two formulations of pravastatin. Data from a crossover, randomised, open-label bioequivalence study in healthy volunteers.

An open-label, randomised, crossover single-dose study, using two periods, two sequences, with a minimum washout period of 7 days, was conducted in order to assess the comparative bioavailability of a pravastatin (CAS 81131-70-6) 40 mg formulation and that of a reference formulation. Blood samples were collected up to +14 h post dosing, the plasma was separated and pravastatin concentrations were determined by high-performance liquid chromatographic method with tandem mass spectrometry detection (HPLC-MS/MS), with a lower limit of quantification of 0.40 ng/mL. Bioequivalence analyses were conducted using two models. The main analysis was done according to a general linear model (model I) using formulation, period and sequence as fixed model effects, and subject(sequence) and residual as random effects; gender-related differences were investigated using ANOVA (model II), including formulation, period, sequence, gender, sequence-by-gender interaction and gender-by-formulation interaction as fixed model effects and subject within sequence-by-gender interaction and residual as random effect. Mean values of the individual Cmax were 126.73 +/- 61.99 ng/mL and 123.52 +/- 52.78 ng/mL for the test and reference, spectively. Mean +/- SD total area under the curve up to the last measurable concentration (AUClast) was 224.26 +/- 104.74 ng x h/mL for the test formulation and 216.55 +/- 80.30 ng x h/mL for the reference formulation. Mean +/- SD total area under the curve (AUCinf) was 226.72 +/- 104.69 ng x h/mL for the test formulation and 218.81 +/- 79.95 ng x h/mL for the reference. Terminal elimination half-life was 2.15 +/- 0.85 h for test and 1.97 +/- 0.54 h for the reference. Ninety percent confidence intervals were comprised within the bioequivalence acceptance criteria (80-125 %) for all of the parameters analysed, both using model I and model II. Model II returned a statistically significant gender effect (p < 0.05) for Cmax, AUClast and AUCinf but the effect became non-significant (p > 0.05) when the dose was adjusted per body weight for all three parameters. The comparison between male and female mean body weight showed a significant difference: p = 0.03, 95 % confidence intervals 68.27-76.93 kg (men), 56.84-60.61 kg (women). These results suggest that the effect of gender in the bioequivalence analysis in model I could be due to a difference in body weight between males and females. Both formulations were shown to be bioequivalent in terms of rate and extent of absorption, irrespectively of the model used.

Comparative study on the bioequivalence of two different gabapentin formulations. A randomised, two-period, two-sequence, crossover clinical trial in healthy volunteers.

The bioequivalence of two capsule formulations containing 400 mg gabapentin (CAS 60142-96-3) was assessed in 24 healthy volunteers in an open, randomised, crossover, 2 periods x 2 sequences, with a minimum washout period of 7 days, single-dose study. Plasma samples were obtained at fixed time points, over 48 h (baseline (pre-dose), +0.5 h, +1 h, +1.5, +2, +2.5, +3, +3.5, +4, +8, +5, +6, +8, +10, +12, +24, +36 and +48 h after administration) and gabapentin concentrations were determined by means of an HPLC-MS method (LLOQ 50.2 ng/mL). Pharmacokinetic parameters used for bioequivalence assessment (AUCtlast, AUCinf and Cmax) were determined from the gabapentin concentration data using non-compartmental analysis. The results showed that all 90 % confidence intervals (obtained by ANOVA) were all within the predefined ranges: 93.87-111.87 % for Cmax 94.04-108.21 % for AUCtlast and 94.23-108.29 % for AUCinf. Consequently, this bioequivalence study was well designed in order to conclude that the test formulation and reference formulation were bioequivalent in terms of rate and extent of absorption.

Truncated AUC in the evaluation of fluconazole bioequivalence. A cross-over, randomised, open-label study in healthy volunteers.

The bioequivalence of two capsule formulations (test and reference) containing 200 mg fluconazole (CAS 86386-73-4) was assessed in 24 healthy volunteers in an open, randomised, crossover, 2 periods x 2 sequences single dose study with a minimum washout period of 14 days. Plasma samples were obtained over 168 h (at baseline, 1 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 5 h, 6 h, 8 h, 12 h, 24 h, 48 h, 72 h, 120 h and 168 h after administration) and fluconazole concentrations were determined by means of an HPLC-WV method (limit of quantification: 0.2 microg/mL). Pharmacokinetic parameters used for bioequivalence assessment (AUClast, AUCinf and Cmax) were determined from the fluconazole concentration data using non-compartmental analysis. The results showed that all 90% confidence intervals (obtained by ANOVA) were 100.89-110.24 for Cmax, 99.07-107.35 for AUClast and 95.42-105.17 for AUCinf, that is, all within the predefined ranges. Furthermore AUCs truncated at 24, 48, 72 and 120 h were also within the 80-125% range. It may be therefore concluded that the evaluated formulations are bioequivalent in terms of rate and extent of absorption.