[Bioavailability of 3 formulations of diltiazem]

The plasma concentration profiles of diltiazem were determined in three series of twelve male volunteers to whom a single doses of 60 mg of diltiazem was administered. Three commercial diltiazem preparations, labelled A, B and C were evaluated. The plasmas were analysed for diltiazem concentration by a new HPLC technique and from the data on concentration profiles, the pharmacokinetic parameters, Cmax, Tmax, T1/2, AUC0-12 and AUC0-infinity were calculated from the function derived by computerized curve fitting and integration. Computerized Pattern Analysis was used for product comparison, based on the plasmatic concentration and the calculated pharmacokinetic data. Differences observed between the three products regarding plasmatic levels and pharmacokinetic, were within the range values defined by individual variation, and were similar to the ones described in the literature for single doses of diltiazem - 60 mg. However, the multiparametric analysis showed that the studied preparations formed two distinct groups: preparation B was different from preparations A and C. This means that preparation B was not bioequivalent to preparations A and C, both considered as bioequivalent.