In Vivo Release Performance of Nifedipine in Dogs From a Novel EUDRAGIT®-Based Multi -Unit Erosion M

The development, characterization, and in vitro evaluation of a novel, multi-unit, erosion matrix pellet system was described in our previous publication.3

The purpose of this study was to evaluate in vivo performance of the erosion matrix pellets prepared with nifedipine and compare their bioavailability with nifedipine immediate-release soft gelatin capsules (10-mg Adalat® and 20-mg gelcaps administered together as one dosage form) in fasted dogs.

A randomized two-way comparative cross-over design was employed for bioavailability studies and four dogs were used. Blood samples were collected over predetermined time intervals up to 12 or 24 hours and analyzed for nifedipine plasma concentrations by an HPLC method for both the dosage forms. A noncompartmental pharmacokinetic model was used to determine parameters, such as Cmax, Tmax, AUC0-24 h, and MRT0-24 h. Results indicated that the bioavailability of nifedipine erosion matrix pellets was four times higher than Adalat® gel caps. Nifedipine was detected in plasma within 1 hour of administration of erosion matrix pellets, thus no significant lag time was observed. Nifedipine multi-unit, erosion matrix pellets showed controlled release for more than 24 hours following zero-order kinetics.