A Novel, Optimized Method to Accelerate the Preparation of Injectable Poly-L-Lactic Acid by Sonication

: Current consensus for preparing injectable poly-L-lactic acid (PLLA) suggests adequate hydration (less than equal to 2-24 hours of reconstitution) of the lyophilized particles before injection, but the volume of reconstitution and the duration of hydration time varies. This study established a method to evaluate the distribution of PLLA particles after hydration and found that longer hydration time increased the effective portion (particles less than 60 μm) of PLLA products. Further investigation of the feasibility of reconstitution with sonication revealed that 2-hour hydration of PLLA powders with additional 5-minute-sonication could yield a comparable particle distribution with 48-hour-hydration of PLLA. Moreover, adding lidocaine into the diluent did not alter the distribution of PLLA particles. We proposed a new, feasible and efficient method of preparing PLLA injectable products: 2-hour hydration of the powders, sonication of the bottle or vial containing PLLA products for at least 5 minutes, and finalization with 1-2 mL of lidocaine immediately before injection. J Drugs Dermatol. 2018;17(8):894-898.