Poly(lactic acid)/poly(lactic-co-glycolic acid)-based microparticles: an overview

Poly(glycolic acid), poly(lactic acid) and poly(lactic-co-glycolic acid) were approved by the United States Food and Drug Administration (FDA) in the 1970s as materials for the manufacturing of bioresorbable surgical sutures, but soon became the reference materials for the preparation of sustained release formulations, especially injectable microparticles. Since the 1986 approval of Decapeptyl® SR, the first product based on PLGA microspheres, more than 15 such products have been approved for clinical use. This article highlights the key steps that brought to the development of injectable poly(lactic acid)/poly(lactic-co-glycolic acid) microparticles for the sustained release of active pharmaceutical ingredients. After a brief history of some pioneering works that opened the field of controlled drug delivery, the key steps that led to the development of these polymers and the approval of the first microparticle-based medicinal products are reviewed. Finally, the general characteristics of these polymers are described and the classical preparation method is explained. Poly(lactic acid)/poly(lactic-co-glycolic acid) microparticles are among the most successful drug delivery systems. The recent approval of new medicinal products based on PLGA microspheres is the proof that pharmaceutical companies have continued to exploit this drug delivery technology. The possible development of generics and the continuous discovery of therapeutic peptides will hopefully further the success of microsphere technology.