Abstract:
This study was performed to investigate the pharmacokinetics and
bioequivalence of the 200-mg innovator's nevirapine (NVP) tablet and those of the
generic NVP tablet of the same strength after a single-dose oral administration in
healthy Thai male volunteers. Pharmaceutical evaluation of each NVP preparation
revealed that pharmaceutical properties of the two products, such as content of active
ingredient, content uniformity, disintegration and dissolution, met the general standard
requirement of USP 24/NF 19.
A Pharmacokinetics and bioequivalence study was performed as a
randomized, parallel, single dose trial. Thirty healthy Thai male volunteers were
enrolled and randomly divided into 2 groups. Each was assigned to receive a single
dose of one tablet of either the 200-mg innovator's or the generic NVP tablet after 8
hours fasting. Mean ± SD of age and BMI between each group were not significantly
different (p> 0.05). Serial sampling of venous blood (5 mL) was obtained before and
at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12, 24, 48, 72, 96, 120, 144 and 168
hours after drug administration. All plasma samples were analyzed for NVP
concentration by validated high-performance liquid chromatography. There were no
statistically significant differences between the two products regarding all
pharmacokinetic parameters (p > 0.05) except for tmax. Mean ± SD of pharmacokinetic
parameters of 200-mg innovator's NVP tablet and 200-mg generic NVP tablet were as
follows: peak plasma concentrations (Cmax) and times to peak plasma concentration
(tmax) were 2.31 ± 0.32 mcg/mL at 2.27 ± 1.33 hr and 2.32 ± 0.44 mcg/mL at 3.27 ±
1.07 hr, respectively. Area under the plasma concentration–time curve from time zero
to 168 hr (AUC0–168) and from time zero extrapolated to infinity (AUC0–∞) were
147.37 ± 23.72 mcg×hr/mL and 159.19 ± 25.99 mcg×hr/mL for the innovator's tablet
and 155.16 ± 27.77 mcg×hr/mL and 170.55 ± 37.52 mcg×hr/mL for the generic tablet.
The relative bioavailability of the generic product was 105.29% and 107.14% of that
of the innovator's product in terms of AUC0–168 and AUC0–∞, respectively. The 90%
confidence intervals of the differences of log-transformed data of Cmax, AUC0 – 168 and
AUC0 – ∞ were 89.15 – 110.50%, 93.85 – 117.50% and 93.38 – 120.59%, respectively.
The powers in statistical tests for these parameters were higher than 80%.
Accordingly, it could be concluded that 200-mg generic NVP tablet was bioequivalent
to the innovator's NVP tablet of the same strength