Dual release behavior of atorvastatin and alpha-lipoic acid from PLGA microspheres for the combination therapy in peripheral nerve injury

The major focus of this study was to prepare poly(lactic-co-glycolic) acid (PLGA) microspheres containing atorvastatin calcium (ATR) in combination with alpha-lipoic acid (ALA). PLGA microspheres will maintain dual-release for providing neuroprotective effects for peripheral nerve injury. For this purpose, microspheres were prepared by spray dryer with different drug:polymer ratios. Microsphere formulations were evaluated for particle size distribution, preparation and encapsulation efficiency, surface morphology, in-vitro release and dose dependent cytotoxicity test with L-929 and B-35 cells. TGA, DSC and FTIR analysis were performed for the investigation of physicochemical properties of the PLGA microspheres. Encapsulation efficiencies were calculated as >70% for ALA and >62% for ATR. FTIR results indicated that there was no interaction between the polymer and the active ingredients. A novel analytical method has been developed and fully validated, which would allow for quantification of ATR and ALA simultaneously. Release profiles showed that ALA is released within the first 17 h and ATR release lasted for 17 days. Finally, results showed that there was no any toxicity associated with ALA and ATR containing PLGA formulations on both B-35 and L-929 cells. It was concluded that PLGA formulations with dual effects are promising systems for the treatment of peripheral nerve injury.