Bioadhesive ranitidine hydrochloride for gastroretention with controlled microenvironmental pH.

Ranitidine hydrochloride is a H(2) receptor blocker used in the treatment of gastric ulcers. Pharmacological factors, in addition to the dosage regimen, favor development of a sustained-release system for ranitidine especially in the therapeutic condition of erosive esophagitis. This investigation delves into the development of bioadhesive type of gastroretentive formulation (tablets) of ranitidine. The effect of mucoadhesive polymers such as Carbopol, hydroxypropyl methyl cellulose, and dextrose were studied. Mucoadhesion, in vitro drug release profile, water uptake, and swelling of the tablet were evaluated. Alkalizing agents were incorporated in an attempt to maintain an alkaline microenvironment within the tablet and improve the stability of the drug in acidic medium. The stability was evaluated using dye test and degradation studies. The drug release profiles were fit into various kinetic models.