MICROSPHERES AS CONTROLLED DRUG DELIVERY SYSTEM: AN UPDATED REVIEW

One of the specialties of microspheres is that they are controlled systems of drug delivery designed for sustained release, to reduce the ordinary dose frequency and easy patient compliance. Controlled drug delivery of microspheres to enhance bioavailability, stability, efficiency, and to reduce the toxicity of drug into the body. The preparation is done for targeted local site delivery with a predetermined rate. Microspheres are a significant part of a novel drug delivery system and have solid spherical particles showing free-flowing properties and the particle size range 1-1000μm. Microspheres are matrix-type systems in which the drug is entrapped, dissolve, suspended. Generally solid or liquid drug entrap, dissolve in a matrix system prepared by several types of microspheres such as Bioadhesive microspheres, Magnetic microspheres, floating microspheres, polymeric microspheres, radioactive microspheres. And the following techniques are used in the preparation of various types of microspheres such as spray drying technique, single emulsion technique, Double emulsion technique, solvent evaporation, phase separation coacervation technique. The review of microspheres follows the introduction, characteristics, Advantages, limitations, types of microspheres, method of preparation, evaluation, and application of microspheres.

Keywords: Bio-adhesive microspheres, controlled drug Delivery, entrap dissolve matrix, enhance the bioavailability, floating microspheres.