Relative oral bioavailability of three formulations of vitamin D3: An open-label, three-treatment study

Background: Supplementation of vitamin D2 or vitamin D3 is recommended for vitamin D deficiency. Weekly supplementation of 60,000 IU of vitamin D3 increases serum 25(OH) D to optimal values. Various marketed forms of vitamin D3 include tablets, capsule, granules and oral solution. The main objective of this study is to compare the relative bioavailability of vitamin D3 oral solution with vitamin D3 tablet and capsule.Methods: This is an open-label, randomized, single-dose, three-treatment study to compare the relative bioavailability of vitamin D3 oral solution with capsule and tablet. Subjects (n=70) were supplemented with single dose of one of these formulations and their blood sample were assessed for Cmax, AUC0-28d and Tmax.Results: The logarithmic transformed data of pharmacokinetic parameters were analyzed for 90% Confidence Intervals (CI) using ANOVA. The mean (90% CI) values of vitamin D3 oral solution against tablet for the ratio of Cmax and AUC0-28d were 113.00 (105.32-121.23) and 105.54 (97.95-113.72) respectively. The mean (90% CI) values of vitamin D3 oral solution against capsule for the ratio of Cmax and AUC0-28d were 115.02 (106.38 - 124.37) and 112.33 (104.44 - 120.81) respectively. These values were within the bioequivalence range of 80-125%.Conclusions: It is concluded that vitamin D3 Oral Solution formulated with nanotechnology is bioequivalent to vitamin D3 tablet and capsule. However, oral solution of vitamin D3 shows higher Cmax and AUC when compared to tablet and capsule formulations.

Large Intra-subject Variability in Caffeine Pharmacokinetics: Randomized Cross-over Study of Single Caffeine Product

Background Average bioequivalence has been criticized for not adequately addressing individual variations. Importance of subjects’ blinding in bioequivalence studies has not been well studied. We explored the extent of intra-subject pharmacokinetic variability and effect of drug-ingestion unawareness in subjects taking single caffeine product. Methods A single-dose randomized cross-over design was used to compare pharmacokinetics of 200 mg caffeine, described as caffeine (overt) or as placebo (covert). Maximum concentration (Cmax), Cmax first time (Tmax), area-under-the-concentration-time-curve, to last measured concentration (AUCT), extrapolated to infinity (AUCI), or to Tmax of overt caffeine (AUCOverttmax), and Cmax/AUCI were calculated blindly using standard non-compartmental method. Percentages of individual covert/overt ratios that are outside the ±25% range were determined. Covert-vs-overt effect on caffeine pharmacokinetics was evaluated by 90% confidence interval (CI) and 80.00–125.00% bioequivalence range. Results 32 healthy subjects (6% females, mean (SD) age 33.3 (7.2) year) participated in the study (28 analysed). Out of the 28 individual covert/overt ratios, 23% were outside the ±25% range for AUCT, 30% for AUCI, 20% for AUCOverttmax, 30% for Cmax, and 43% for Tmax. There was no significant covert-vs-overt difference in any of the pharmacokinetic parameters studied. Further, the 90% CIs for AUCT, AUCI, Cmax, AUCOverttmax, and Cmax/AUCI were all within the 80.00–125.00% bioequivalence range with mean absolute deviation of covert/overt ratios of 3.31%, 6.29%, 1.43%, 1.87%, and 5.19%, respectively. Conclusions Large intra-subject variability in main caffeine pharmacokinetic parameters was noted when comparing an oral caffeine product to itself. Subjects’ blinding may not be important in average bioequivalence studies.

Bioequivalence Study of Pantoprazole Sodium-HPBCD and Conventional Pantoprazole Sodium Enteric-Coated Tablet Formulations

The objective of this study was to investigate the bioequivalence of two formulations of 40 mg pantoprazole sodium enteric-coated tablets: Tripepsa as the test and Pantocid as the reference. The two products were administered as a single oral dose according to a randomized two-phase crossover with a 1-month washout period in 25 healthy Indian volunteers. After drug administration, serial blood samples were collected over a period of 30 hours. Plasma pantoprazole concentrations were measured by high-performance liquid chromatography with UV detection. Pharmacokinetic parameters were analyzed based on noncompartmental analysis. The logarithmically transformed data of and were analyzed for 90% confidence intervals (CI) using ANOVA. The mean (90% CI) values for the ratio of and values of the test product over those of the reference product were 90.21 (83.69–97.24) and 108.68 (100.21–117.86), respectively (within the bioequivalence range of 80–125%). On the basis of pharmacokinetic parameters including , , and values, both the formulations were bioequivalent.

Bioequivalence Study of Donepezil Hydrochloride Tablets in Healthy Male Volunteers

The objective of this study was to investigate the bioequivalence of two formulations of 5 mg donepezil HCL tablets: Tonizep as the test and Aricept as the reference. The two products were administered as a single oral dose according to a randomized two-phase crossover with a 3-week washout period in 20 healthy Thai Male volunteers. After drug administration, serial blood samples were collected over a period of 216 hours. Plasma donepezil concentrations were measured by high performance liquid chromatography with UV detection. Pharmacokinetic parameters were analyzed based on noncompartmental analysis. The logarithmically transformed data of AUC0–∞ and were analyzed for 90% confidence intervals (CI) using ANOVA. The mean (90% CI) values for the ratio of AUC0–∞ and values of the test product over those of the reference product were 1.08 (1.02–1.14) and 1.08 (0.99–1.17), respectively (within the bioequivalence range of 0.8–1.25). The median for the test product was similar to that of the reference product (2.0 hr), and the 90% CI for the difference between the two preparations was –0.19 to 0.29 hr and within the bioequivalence range of ± 20% of the of the reference formulation. Our study demonstrated the bioequivalence of the two preparations.