EXAMINATION OF 2 SUSTAINED-RELEASE NIFEDIPINE PREPARATIONS IN HUMANS AND IN PIGS

In the present study, the ability of the pig to discriminate the in-vi vo release characteristics of two 60 mg sustained release nifedipine f ormulations, an experimental formulation (Faulding) and Procardia XL ( Pfizer), under both fasting and fed conditions was assessed. These for ms had previously been evaluated in humans, where an alteration in the release profile of the experimental formulation was noted following a dministration with food. 12 Large White female pigs (mean weight 38 kg ) were divided into two groups and each group was orally administered one of the two products under both fasting and fed conditions. The mea n area under the plasma concentration-time curve was not significantly different between the formulations under both conditions. The mean ma ximum observed plasma concentration (C-max) was significantly higher f or the experimental formulation when compared against Procardia XL und er both fasting (P<0.05) and fed (P<0.05) conditions. Peak concentrati ons were achieved at approximately 6 h for the experimental formulatio n and 12 h for Procardia XL. The time for which the plasma concentrati on exceeded 75% of C-max was approximatley 2.5-fold greater for Procar dia XL than for the experimental formulation. There were no significan t food effects on the relative bioavailability nor release profiles of thr two formulations. The results obtained suggest that the pig may b e a useful model in differentiating the release profiles of nifedipine formulations for the fed state in humans as results were similar to t he human-fed study, but dissimilar to the human-fasted study.