European Journal of Biomedical and Pharmaceutical Sciences

MUCOADHESIVE MICROSPHERES: A PROMISING APPROACH FOR ORAL DRUG DELIVERY

S. S. Dali* and P. Kadu

ABSTRACT

Mucoadhesive microspheres are one of the most promising novel techniques for drug delivery. Mucoadhesive systems offer a sustained drug release method, thus enhancing drug absorption in a site-specific manner. Microspheres have very small sizes and provide efficient carrier capacities. Mucoadhesive systems therefore play a vital role in drug delivery systems. Mucoadhesive microspheres interact with mucous of gastrointestinal tract (GIT) and are considered to be localized or trapped at the adhesive site by retaining a dosage form at the site of action, or systemic delivery by retaining a formulation in intimate contact with the absorption site which may result in prolonged gastric residence time as well as improvement in intimacy of contact with underlying absorptive membrane to achieve better therapeutic performance of drugs. Mucoadhesion is a two-step procedure, and its mechanism can be explained by combining theories of wetting, mechanical interlocking, electronic transfer, adsorption, fracture, and diffusion interpenetration, as deemed suitable. Mucoadhesive microspheres offer added advantages of reliability, safety, specificity, prolonged action, delayed release, and enhanced activity. These systems can be prepared by solvent evaporation, ionotropic gelation, emulsion solvent diffusion, spray drying, and solvent removal. The resulting microspheres are characterized using a number of parameters using in vivo and in vitro techniques. This review article gives an overview of mucoadhesive microspheres, preparation methods, characterization, applications, and recent developments.

Keywords: Microspheres, mucoadhesion, mucoadhesion theories, mucoadhesive polymers and evaluation methods.