Comparative pharmacokinetics of different oral nifedipine preparations in healthy brazilian volunteers

RESUMO

The pharmacokinetics of different pharmaceutical preparations of oral nifedipine-Adalat (capsule), Oxcord and Cardalin (tablets)-was determined after administration of single oral doses of 10 mg to nine healthy young Brazilian volunteers (7 men). There no significant changes in heart rate or systolic and diastolic blood pressure measured in the sitting position within 8 h of nifedipine administration to these normotensive volunteers. No side effects were reported by the volunteers or observed by the attending physicians during the study. No significant differences were observed among the three preparations in relation to the following pharmacokinetic parameters obtained from the plasma concentration-time curves area under the curve (AUC), slope (beta) and half-life (T½) of the elimination phase, volume of distribution (Vd/F) and total body clearance (CL/F), both expre4ssed as functions of the oral bioavailability (F) of nifedipine. The peak, plasma concentration of nifedipine (C max) and the time to reach C max (T max) were not different for the rwo tablet preparations. However, C max was significantly higher, and T max was significantly shorter for the capsule. These data indicate that the capsule and the tablet preparations are not bioequivalent