Rapamycin Release Study of Porous Poly(L-lactic acid) Scaffolds, Prepared via Coaxial Electrospinning

摘要

Rapamycin (RAPA) is currently used in treatment of arteriostenosis. However, its half-life is only 57 similar to 62 h, which greatly limits its application. Preparation of RAPA sustained-release carrier is therefore necessary. By combing the versatility of coaxial electrospinning, the RAPA-loaded poly(L-lactic acid) (PLLA) porous scaffolds were fabricated with PLLA/Poly polyethylene glycol (PEG) mixture as shell solution and RAPA as core solution, respectively. The RAPA-loaded PLLA small-diameter (<6 mm) scaffolds were fabricated through a series of experiments to optimize the preparation conditions. The uniform RAPA-Loaded PLLA fibers, with few beads and porous surface, were fabricated when the ratio of PLLA to PEG was 7/3, PLLA concentration was 3% applied voltage was 7.5 kV, and pump speeds were V-core = 0.1 rnUh and V,hen- 1 rnUh, respectively. The T-IRresults indicated that the RAPA was successfully, encapsulated in the core-shell structure of the PLLA fibers. The RAPA burst release from the porous PLLA scaffolds was not obvious while its obviously sustained release effect lasted for up to 20 days. The RAPA release curves were fitting and showed that the fitting degree was highest with First-order kinetics models, which best described the release behavior for the in vitro release of the RAPA-loaded PLLA porous scaffolds. Moreover, the Higuchi kinetics models relatively matched the RAPA release curves from the PLLA porous scaffolds, and also indirectly reflected the PLLA scaffolds' porous structure. This study was aimed at revealing the relationship among the drug release systems using scaffolds and would be beneficial to the design and optimization of drug carrier scaffolds.