Bioequivalence of two formulations of pregabalin 150-mg capsules under fasting conditions in healthy male subjects
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BACKGROUND

Pregabalin binds to the α2δ auxiliary subunit of voltage-gated calcium channels, which are widely distributed throughout the central and peripheral nervous systems and modulate calcium-dependent neurotransmitter release. Pregabalin is indicated for the treatment of peripheral and central neuropathic pain, partial seizures with or without secondary generalization, and treatment of generalized anxiety disorder (GAD).

OBJECTIVE

The purpose of this study was to assess the bioequivalence of two different formulations of pregabalin 150-mg capsules in healthy Korean male subjects under fasting conditions.

METHODS

This bioequivalence study was based on an open-label, single-dose, randomized, 2-period, 2-sequence crossover design with a washout period of 7 days. Blood samples for pharmacokinetic (PK) evaluation were collected up to 24 hours postdose. Plasma concentrations of pregabalin were determined using a validated LC-MS/MS method. PK parameters were determined using noncompartmental analysis. Bioequivalence was assumed if the 90% confidence intervals (CIs) for the test/reference ratios of log-transformed Cmax and AUClast values met the bioequivalence criteria specified by Korean regulatory guidelines (90% CI 0.8 - 1.25).

RESULTS

The extent of exposure in terms of AUClast amounted to 26,018.3 - 3,580.8 µg×h/L for the test formulation and 25,680.2 ± 3,083.6 µg×h/L for the reference formulation. Cmax reached values of 4,782.7 ± 1,124.2 µg/L and 4,654.0 ± 911.4 µg/L for the test product and reference product, respectively. The geometric mean ratio and 90% CIs of the test product to the reference product were 1.0132 (0.9862 - 1.0351) for AUClast and 1.0153 (0.9351 - 1.1044) for Cmax, which were well within the range necessary to establish bioequivalence (90% CI 0.8 - 1.25).

CONCLUSIONS

The bioequivalence between test and reference formulations under fasting conditions was confirmed both in terms of the rate and extent of absorption.
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