Preparation, characterization and evaluation of ranitidine hydrochloride-loaded mucoadhesive microspheres

Mucoadhesion enables localization of drugs to a defined region of the gastrointestinal tract through attractive interactions between polymers composing the drug delivery devices and the mucin layer of the intestinal epithelium. Thus, this approach can be used for enhancement of the oral bioavailability of the drug.

The current communication deals with the development of ranitidine hydrochloride-loaded chitosan-based mucoadhesive microspheres.

Microspheres were prepared by water-in-oil emulsion technique, using glutaraldehyde as a cross-linking agent. The effect of independent variables like stirring speed and polymer-to-drug ratio on dependent variables, i.e. percentage mucoadhesion, percentage drug loading, particle size and swelling index, was examined using a 3(2); factorial design.

The microspheres were discrete, spherical, free-flowing and also showed high percentage drug entrapment efficiency (43-70%). An in vitro mucoadhesion test showed that the microspheres adhered strongly to the mucous layer for an extended period of time. The RC 4 batch exhibited a high percentage of drug encapsulation (70%) and mucoadhesion (75%). The drug release was sustained for more than 12 h. The drug release kinetics were found to follow Peppas' kinetics for all the formulations and the drug release was diffusion controlled.

The preliminary results of this study suggest that the developed microspheres containing ranitidine hydrochloride could enhance drug entrapment efficiency, reduce the initial burst release and modulate the drug release.