Bioavailability of nifedipine: a comparison between two preparations.

Area of Science:

• Pharmacology
• Clinical Pharmacy

Background:

• Nifedipine is a widely used calcium channel blocker for managing hypertension and angina.
• Different pharmaceutical formulations can influence drug absorption and therapeutic outcomes.

Purpose of the Study:

• To compare the pharmacokinetic profiles of nifedipine capsules and tablets in healthy volunteers.
• To assess the impact of formulation on nifedipine absorption and peak serum levels.

Main Methods:

• A randomized cross-over study involving eight healthy volunteers.
• Administration of single 10 mg doses of nifedipine capsules (Adalat) and tablets (Taro) under fasting conditions.
• Measurement of serum nifedipine concentrations over time to determine pharmacokinetic parameters like AUC and peak levels.

Main Results:

• No significant difference was observed in the overall bioavailability (AUC0-infinity) between nifedipine capsules and tablets.
• Nifedipine capsules demonstrated significantly higher peak serum levels (162.4 ng/mL at 30 min) compared to tablets (43.0 ng/mL at 1-2 h).
• Faster absorption from capsules correlated with clinical symptoms of vasodilation.

Conclusions:

• While overall bioavailability is similar, the faster absorption rate of nifedipine capsules may lead to different therapeutic equivalence compared to tablets.
• The choice between nifedipine capsule and tablet formulations may depend on the specific therapeutic indication and desired onset of action.