Abstract

MICROSPHERES –A REVIEW

Abstract

The concept of drug delivery has been revolutionized. The current focuses on microspheres which are small, solid particles ranging in size from 1 to 1000 μm. These are made of polymeric, waxy, or other protective materials i.e. biodegradable synthetic polymers and natural products such as starches, proteins, fats and waxes. The natural polymers include albumin and gelatin; the synthetic polymers include polylactic acid and polyglycolic acid etc. Microspheres have been incorporated with antineoplastic drugs, steroid hormones, narcotic antagonists, luteinizing hrh analogs, and other macromolecules. General methods of preparation are emulsion techniques, phase separation coacervation techniques, spray drying and spray congealing and solvent extraction, in-situ polymerisation etc. Advantages of microspheres use are targeted drug delivery, optimal therapeutic effects and minimum side effects. Recent trends are floating microspheres, radio immobilisation using microspheres.

Keywords: Microspheres, floating microspheres, microencapsulation, spray coating and pan coating, phase separation coacervation.