[Study on dissolution test in vitro and bioavailability of oral osmotic pump of verapamil hydrochloride]

This paper deals with the evaluation of osmotic pump of verapamil hydrochloride tablet (C) by measuring in vitro/in vivo test. The results showed that the dissolution behaviors were of zero-order kinetic and release constant in vitro (Kr) of C was 9.9450. The plasma levels of Ver.HCl in eight volunteers following single and multiple oral doses of these dosage forms were determined using HPLC method. The pharmacokinetic parameters were fitted by nonlinear least square method with a computer on the basis of two-compartment model. The pharmacokinetic parameters of Cmax, Tmax, t1/2, Ka, K10 and K21 were calculated. The bioavailability of tablet C relative to B and A was 101.7%, 96.16% respectively. A significant correlation was found between in vitro dissolution and in vivo absorption.