Morphology prediction of block copolymers for drug delivery by mesoscale simulations

Abstract

Polymeric drug carriers have traditionally been considered important for enhancing drug stability and solubility, and improving transport properties of pharmaceutical molecules. Two polymers extensively studied in this regard are poly(lactide) (PLA) and poly(ethylene oxide) (PEO). Nonetheless, a systematic investigation of the main structural and physical factors influencing the ultimate morphology and structure of these block polymer nanoscopic aggregates is still lacking. In this work we report the results of a complete study on the self-assembly of (D-L)-PLA/PEO di/triblock copolymers in aqueous environment and in the presence of a model drug based on a molecular simulation recipe. In detail, atomistic molecular dynamics simulations were used to obtain dissipative particle dynamics (DPD) input parameters, and this mesoscale technique was employed to derive the entire phase diagrams for these systems. Scaling laws for micellar dimensions were applied, and micellar characteristics (e.g., aggregation number) were derived accordingly. The effect of drug-loading on the nanocarrier aggregated morphology was also investigated.