PLLA

Poly-L-lactic acid (PLLA) is a biodegradable polyester derived from the L enantiomer of lactic acid. It forms semi-crystalline, relatively rigid polymers with high tensile strength compared with non-crystalline polylactides. PLLA is produced primarily by ring-opening polymerization of L-lactide, often with catalysts such as tin octoate, to achieve targeted molecular weight and crystallinity.

Biodegradation and biocompatibility: It hydrolyzes into lactic acid and is metabolized via normal pathways; the rate of degradation depends on molecular weight, crystallinity, geometry of the implant, and local conditions; degradation typically occurs over months to years, depending on formulation and site of use.

Applications: medical implants and devices including absorbable sutures, orthopedic screws, pins, and plates; tissue engineering scaffolds; cosmetic rejuvenation via PLLA-based fillers that stimulate collagen production.

Regulation and safety: PLLA materials have been widely studied and used in medical applications, with approvals from regulatory agencies for various devices and formulations. Sterilization methods include ethylene oxide and gamma irradiation. Risks in some filler applications can include localized inflammation or granuloma if used improperly or in sensitive individuals.

Overview: PLLA is valued in biomedicine for its combination of biocompatibility, gradual resorption, and mechanical properties suitable for temporary support and tissue remodeling, making it a common choice for implants, scaffolds, and cosmetic fillers.