Intra-gastric performance and bioavailability study of a new per-oral bioadhesive Verapamil HCl matrix tablet in dogs.

In a previous study, we developed a per-oral extended--release bioadhesive matrix tablet for verapamil HCl (VP). The system combined both strong bioadhesion and sustained release properties in vitro. The purpose of this study is to evaluate the in vivo performance of the prepared bioadhesive tablets (B). The conduction of a periodic X-ray imaging of the abdomen of beagle dogs, after administration of B containing 12% barium sulfate, was used to evaluate the intra-gastric performance. The VP concentrations in blood samples taken at specified times after oral administration of B to fasted beagle dogs were determined and compared with those obtained after administration of a commercial sustained release VP tablets (Manidon 120 R). The X-ray images showed that bioadhesive tablets remained almost at the same place in the stomach for at least 6 hours while it disappeared after 1 hour in case of the control tablets. No statistical difference was seen between the Cmax, tmax, AUC, t1/2, and MRT for B compared to Manidon. The Cmax was found to be 51.4 +/- 15.5 and 48.6 +/- 17.9 (ng/ml) for Manidon and B, respectively and the corresponding tmax were 7.0 +/- 1.9 and 6.0 +/- 0, respectively. The AUCO-. for Manidon and B were 949.84 +/- 245.11 and 722.92 +/- 144.42 ng.h/ml, respectively. So, the prepared B tablets can be considered bioequivalent to the commercial Manidon Retard product.