Freeze-Dried Highly Porous Matrix as a New Gastroretentive Dosage Form for Ecabet Sodium: In Vitro and In Vivo Characterizations

The aims of the present study were to prepare hydroxypropylmethyl cellulose-based matrix tablets prepared using the freeze-drying method for gastroretentive delivery of ecabet sodium (ECS), a locally acting antigastric ulcer drug, and to perform in vitro/in vivo characterizations.The freeze-dried gastroretentive tablets (FD-GRTs) had porous structures, while they had good friability as a pharmaceutical dosage form. The porous structures lowered the tablet density, allowing the tablet to float without any lag time. Buoyancy of FD-GRT was maintained until they were entirely disintegrated during an in vitro release study. Release rate of ECS could be controlled by the amount of ethylcellulose (EC) in FD-GRT. As amount of EC in the composition was increased, there was a decrease in both release rate and erosion rate of FD-GRT. When administered to a miniature pig, FD-GRT remained in the stomach for more than 12h, which was significantly longer than a conventional sustained release tablet. The new FD-GRT do not contain any excipients for buoyancy and do not require any lag time for buoyancy, consequently it could be considered to be safer and more effective than conventional floating-type GRT.