PLGA

Poly(lactic-co-glycolic acid) (PLGA) is a biodegradable, biocompatible copolymer composed of lactic acid (LA) and glycolic acid (GA) units. It is typically prepared by ring-opening polymerization of the cyclic dimers lactide and glycolide, yielding random or block copolymers with ester linkages. The material’s properties—such as degradation rate and mechanical strength—depend on the lactic:glycolic ratio, overall molecular weight, and crystallinity. Common compositions include PLGA with LA:GA ratios of 50:50, 65:35, and 75:25.

PLGA degrades in vivo through hydrolysis of ester bonds, producing lactic acid and glycolic acid that are metabolized by the body. Degradation rate increases with higher glycolic content, lower molecular weight, and more hydrophilic end groups. Conversely, higher lactic content and greater crystallinity slow degradation. Acid-terminated PLGA tends to hydrolyze faster than ester-terminated polymers. PLGA can be processed into microspheres, nanoparticles, films, fibers, and scaffolds using solvent evaporation, emulsion, phase separation, or melt-processing techniques. It is generally regarded as biocompatible, though localized pH lowering during degradation can provoke transient inflammation.

Applications include controlled-release drug delivery systems, injectable depots, implantable devices, and tissue engineering scaffolds. By adjusting LA:GA ratio, molecular weight, end-group chemistry, and particle size, manufacturers tailor degradation and drug-release profiles. PLGA has a long history of clinical use and regulatory approval for various medical devices and pharmaceutical formulations, reflecting its prominence as a versatile biodegradable polymer in biomedicine.