Recent biomedical applications and patents on biodegradable polymer- PLGA

INTRODUCTION Extensively used polymers in biomedical applications are naturally occurring or synthetic compounds consisting of large molecules obtained from linking of simple monomers. Potential biomedical applications of these polymers include carrier based drug delivery systems, tissue engineering scaffold and cell culture supports [1]. Polymer based drug delivery system can control the rate of drug release, enhance effective drug solubility, minimize drug degradation, contribute to reduced drug toxicity and facilitate control of drug uptake, which significantly contributes to therapeutic efficiency of a drug [2]. Some desirable characteristics of polymer for drug delivery system should be [3]:  Natural or synthetic origin, less toxicity and biodegradable in nature  In vivo degradation at a well-defined rate and degraded products readily excreted from the body.  No toxic endogenous impurities or no residual chemicals used in their preparation, e.g. cross linking agents Examples of naturally derived polymers include starch, chitosan, alginate, collagen and synthetic polymers includes poly (alkylcyanoacrylates), poly (anhydrides) and polyesters [4]. Amongst them, the thermoplastic aliphatic polyesters, such as polylactic acid, poly glycolic acid and especially the copolymer poly(lactic-co-glycolic acid) (PLGA) used as biomaterials for biomedical applications on the basis of available toxicological and clinical data [5]. The family of homo and co-polymers derived from lactic and glycolic acids monomers have received a considerable attention as excipients since 1973 in pharmaceutical industry due to its In the area of carrier drug delivery system, various natural and synthetic polymers are used. The natural polymers have many formulation problems such as instability, irreproducibility, changes in aesthetics on storage, uncontrollable formulation characteristics. On the other hand, synthetic polymers are either modified from natural polymers or completely synthesized from synthetic monomers. They possess properties that seem to solve the problems of natural polymers and more stable than the natural polymers. In other words, they have mechanical properties that match their application, provide sufficiently stability during formulation, transportation and use. Synthetic polymers have long shelf life as compare to natural polymers. Examples of synthetic polymers used in drug delivery systems are polymethacrylates (Eudragit-E, Eudragits-L, Eudragit-S, Eudragit-RS, Eudragit-RL), Polyacrylic acid (carbomer), Cellulose ethers (methylcellulose, ethylcellulose, hydroxypropyl methycellulose) and Polyesters (copolymers of lactic acid, glycolic acid and ε-hydroxycaproic acid). This review presents the recent applications and patents of poly(lactic-co-glycolic) acid (PLGA) in biomedical applications with a focus on the understanding of some specific physicochemical characteristics which play an important role in their characterization. Home Page: http://ijppsjournal.org International Journal of Pharmacology and Pharmaceutical Sciences