Assessment of the Effect of PLGA Copolymers and PEG on the Formation and Characteristics of PLGAPEGPLGA Coblock Polymer Using Statistical Approach

Purpose: To assess the effect of the lactic acid (LA)toglycolic acid (GA) molar ratio and polyethylene glycol (PEG) concentration on the formation of polylactide coglycolide acid (PLGA)PEGPLGA coblock polymers simultaneously using statistical approach. Methods: A 22 full factorial design with the addition of a point in the center of the design, namely curvature, was applied. Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR) were performed to confirm the formation of the coblock polymer. Simvastatin (SMV), a drug model was incorporated into the nanopolymeric micellar (NpM) of PLGAPEGPLGA followed by solubility phase, particle size, zeta potential, and entrapment efficiency characterizations. Results: FTIR, DSC, and NMR successfully confirmed the formation of coblock polymers. Solubility of SMV increased from 2 to 44folds depending on coblock concentration with entrapment efficiency of 59%80%. The NpM had size in the range of 206 to 402 nm with negative zeta potential. LA to GA ratio had greater effect on particle size reduction and increasing of copolymer length. In addition, it had higher contributions on increasing of solubility and entrapment efficiency of SMV than PEG. Conclusion: According to these findings, the LA to GA ratio and PEG concentration gained a great consideration in order to prepare the PLGAPEGPLGA coblock which fulfilled the quality target product profile of NpM delivery system.