Development of novel spray coated soft elastic gelatin capsule sustained release formulations of nifedipine, bioavailability and bioequivalence of verapamil HCL controlled release formulations, pharmacokinetics of terbinafine after single oral doses in ra

This dissertation describes the development of a new sustained release formulation of nifedipine. The new formulation was developed by coating commercially available immediate release soft elastic gelatin capsules using a spray coating technique with two different polymeric combinations. Dissolution studies were conducted and showed that controlled release of nifedipine was obtained by increasing the ratio of the water insoluble polymer in the coat and increasing the percent weight gain of the coating. Simulated plasma concentration versus time profiles after administration of 30 mg dose of selected formulations showed a prolonged nifedipine release with concentrations above the minimum effective concentration for up to 12 hours.; Bioavailability and bioequivalence of tableted test formulation of verapamil HCL was determined in 8 volunteers and compared to Covera HSRTM under fed and fasting conditions. The 90% confidence intervals for individual percent ratios of the Cmax, AUC0--58 and AUC 0--infinity were not within the range of 80--125% in both fed and fasted states, suggesting that these formulations are not bioequivalent. However, the bioavailability of verapamil from the new formulation was higher in the fed state but this effect was not statistically significant.; Pharmacokinetics of terbinafine administered orally at single doses of 15, 30, 60 and 120 mg were determined in raptors to recommend an appropriate dosing scheduled for terbinafine in the treatment of Aspergillosis. Calculation of steady state trough terbinafine plasma concentration after administration of daily doses of 15 or 30 mg/day showed that 30 mg daily dose of terbinafine administered orally in raptors produces a steady state trough terbinafine plasma concentration above the minimum inhibitory concentration (MIC) of (0.8--1.6) mug/ml against aspregillus fumigatus. From the data, 30 mg per day oral dose of terbinafine should be the recommended dose for treatment of aspergillosis in raptors. Approximate pharmacokinetic linearity of terbinafine was demonstrated for AUC0--t in the dose range of 15--120 mg while non-linearity for Cmax in the same dose range was demonstrated using the power model.