Polymeric Novel Vesicular Drug Delivery System: An Updated Overview of Microspheres

Abstract

Microspheres are categorized under the vesicular drug delivery system, encapsulated by proteins or synthetic polymers which are biodegradable in nature and ideally having a particle size less than 200 μm. The internal structure of the microspheres can vary as a function of the microencapsulation process employed. The encapsulation is carried out by various preparation methods. Microspheres are multiparticulate drug delivery systems which are prepared to obtain prolonged or controlled drug delivery to improve bioavailability, stability and to target the drug to specific site at a predetermined rate. Drugs can be targeted to specific sites in the body using microspheres. The rate of drug release from the microspheres dictates their therapeutic action. Release is governed by the molecular structure of the drug and the polymer, the resistance of the polymer to degradation, and the surface area along with the porosity of the microspheres. This article aims to provide a comprehensive review of advantages, methods of preparation, mechanism, routes of administration, different types of microspheres based on natural and synthetic biodegradable polymers and application of biodegradable polymeric microspheres.