Variables Influencing the Drug Entrapment Efficiency of Microspheres: A Pharmaceutical Review 

By Ram Chand Dhakar, Sheo Datta Maurya, Bhanu PS Sagar, Sonia Bhagat, Sunil Kumar Prajapati, Chand Prakash Jain 


Novel drug delivery systems have several advantages over conventional multi dose therapy. Much research effort in developing novel drug delivery system has been focused on controlled release and sustained release dosage forms. Now considerable efforts are being made to deliver the drug in such a manner so as to get optimum benefits. There are various approaches in delivering a therapeutic substance to the target site in a sustained controlled release fashion. One such approach is using microspheres as carriers for drugs. Microspheres received much attention not only for prolonged release, but also for targeting of anticancer drugs to the tumor.  Microencapsulation is used to modify and delayed drug release form pharmaceutical dosage forms. Microspheres efficiently utilized in controlled delivery of many drugs but wastage of drug due to low drug entrapment efficiency is the major drawback of such microparticulate system.  Well designed microspheres can overcome such problems by enhancing the loading efficiency of a particular drug and minimizing the wastage of drug. It is the reliable means to increase the loading efficiency, if optimize the formulation as well as process variables. This will only possible by understanding the effect of various variables which affect the drug entrapment efficiency of these microspheres. The intent of the paper is to highlight the various variables which influence the drug entrapment efficiency along with method of preparation and characterization of microspheres. 

Key Words: Novel drug delivery system, Controlled release, Microspheres, Drug entrapment, formulation variables, process variables.

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