effects of weak and strong cation exchange resins on moisture uptake behavior of ranitidine hydrochloride

the aim of the present research was to study the effects of weak cation exchange resins, polacrilex with exchangeable h+ and polacrillin potassium and strong cation exchange resin sodium polystyrene sulfonate on water uptake behavior of ranitidine hydrochloride. drug resin complexes (drc) were prepared and evaluated for the percentage of moisture gain when placed in a humidity chamber at 40e2 °c and 75e5% rh for 17 h as compared to drug and free resins under the same condition. equilibrium moisture content (emc) under different humidity conditions and the rate and extent of moisture uptake in the presence (15 watt florescence light) and absence of light under 40e2 °c and 75e5% rh were also calculated for drcs, drug and unloaded resins. drc 264 (containing polacrilex with h+) gained minimum weight (10.22%) maintaining free flowing characteristics whereas other resinates showed higher weight gain and formation of sticky mass while ranitidine hcl turned liquid with gain of 28.11% weight. the rate of moisture uptake by ranitidine hcl was found to increase in the presence of light with slight difference in extent, whereas moisture uptake rate was independent of light in the case of resins. even though drc 264 contained ranitidine hcl, the moisture uptake rate was unaffected by light and saturation in moisture gain was seen just at 6 h. thus, loading ranitidine hcl on polacrilex resin with exchangeable h+ significantly improves its moisture resistance and may not require very tight environmental controls during its formulation.