polyDLlactic

Poly(D,L-lactic acid), abbreviated PDLLA, is an aliphatic polyester consisting of randomly arranged D- and L-lactic acid units. It is the racemic version of polylactic acid (PLA) and is typically prepared by ring-opening polymerization of DL-lactide or by polycondensation of lactic acid.

PDLLA is largely amorphous, with little or no crystallinity, which leads to a relatively uniform and often faster hydrolytic degradation compared with crystalline PLLA. It exhibits a glass transition in the mid-range, typically around 50–60°C, and generally lacks a distinct melting point due to its amorphous nature. Mechanical properties depend on molecular weight and processing, but PDLLA is usually more flexible than semicrystalline PLA.

Degradation occurs hydrolytically to lactic acid, which is metabolized by natural pathways in the body. Degradation rate increases with lower molecular weight and higher surface area and is often faster than that of semicrystalline PLLA. PDLLA is widely regarded as biocompatible and has been used in medical devices and drug-delivery systems, although local acidity from degradation can influence tissue response in some applications.

PDLLA is used in resorbable sutures, tissue engineering scaffolds, and various drug-delivery systems, as well as ophthalmic devices. It can be processed by melt extrusion, solvent casting, electrospinning, and additive manufacturing methods, with processing choices impacting crystallinity and degradation behavior.

Regulatory clearance for PDLLA-based materials varies by product and jurisdiction, reflecting the specific formulation, additives, and intended use.