Studies of Moisture Absorption and Development of Stable Ranitidine Hydrochloride Tablets

In this study, an investigate effect of moisture absorption by ranitidine and resinates used to improve stability of ranitidine hydrochloride tablets. Moisture absorption by ranitidine at three different level of relative humidity (RH) has been studied. Percentage of moisture absorption at 22% was low as compared to 57% and 75% RH. To eliminate deliquescent tendency of drug, weak cation-exchange resins Indion 204, Indion 264 and Indion 254 were used in formulation as complexing agent. The drug loading process was optimized with respect to drug: resin ratio and pH of loading solution. The complexes were evaluated for bulk density, angle of repose, stability and in-vitro drug release. Optimum drug loading was at pH of 4.0 in drug: resin ratio of 1:1. In-vitro drug release studies showed more than 90% drug release from the optimized formulation within 30 min. X-Ray diffraction studies revealed ranitidine hydrochloride to be present in amorphous form in resinates. Tablets were prepared containing Indion 204: drug complex using different diluents. Tablets containing resinates and commercial products were exposed to 75%RH to observe their effect on moisture absorption. The type of dosage form also influenced moisture absorption. Uncoated tablets absorbed maximum amount of moisture, capsule intermediate while coated tablets absorbed minimum. Formulated tablets containing microcrystalline cellulose absorbed minimum amount of moisture as compared to formulations containing lactose and mannitol. Tablets containing resinates exhibited similar dissolution profile with commercial tablets. Indion 204 was found to be better complexing agent for reducing the hygroscopicity and to design stable ranitidine hydrochloride tablets.