Comparative bioavailability of two irbesartan/hydrochlorothiazide tablet formulations in Indonesian healthy subjects

Aim: The bioavailability of two 300 mg irbesartan (CAS 138402-11-6)/12.5 mg hydrochlorothiazide (CAS 58-93-5) tablet formulations was compared, using Co-Irvell® tablets as test formulation and the originator product as reference formulation. Methods: Twenty-four subjects were included in this single-dose, open-label, randomized two-way crossover study following an overnight fasting. A two-week wash-out period was applied. Blood samples were drawn up to 48 h following drug administrations. Irbesartan and hydrochlorothiazide plasma concentrations were determined by liquid chromatography-tandem mass spectrometry method with TurboIonSpray mode. Pharmacokinetic parameters AUC _0-t, AUC _0-∞, C _max andt were determined and used for bioequivalence evaluation after log-transformation, whereas t _max ratios were evaluated non-parametrically. Results: The estimated point and 90% confidence intervals (CI) for AUC _0-t, AUC _0-∞, C _max and t for irbesartan were 97.74% (85.40-111.86%), 96.36 % (83.25-111.55 %), 103.30% (90.65-117.71%), 92.38% (82.68-103.21%) and for hydrochlorothiazide, 106.30 % (97.72-115.63 %), 106.28% (98.14-115.10%), 108.01% (95.48-122.18 %), 105.52% (96.70-115.14 %), respectively. Conclusion: These results indicated that the two formulations of irbesartan/hydrochlorothiazide were bioequivalent; therefore they may be prescribed interchangeably.