Fabrication of porous poly(L-lactide-co-ε-caprolactone) micropowder for microbubble effect and ultrasound-mediated drug delivery

Biodegradable elastic poly(L-lactide-co-ε-caprolactone) (PLCL) copolymer (50:50, lactide:caprolactone molar ratio) was synthesized and porous PLCL micropowders was fabricated by a simple method involving rapid cooling of 0.1, 0.5, and 1% (wt/vol) PLCL/dioxane spray into liquid nitrogen. The physicochemical properties of the porous PLCL micropowders were examined by measuring their pore size, pore morphology, and microbead size using a scanning electron microscopy (SEM) and dye and temozolomide (TMZ)-release testing under ultrasound. Human U-87MG, glioblastoma (GBM) cell culture tests were performed to evaluate cell cytotoxicity by released drug from PLCL micropowders. In this study, the porous PLCL micropowders prepared from 1 wt%/vol% PLCL solutions showed a highly porous structure, satisfactory mechanical properties, and optimal drug release efficiency compared with those produced from 0.1 or 0.5 wt%/vol% solutions. The results of the accumulated release test with the results of the absorbance of the dye initially applied, it was confirmed that more than 80% of the added dye was trapped inside the micropowder, and clearly GBM cytotoxicity effect could be observed by the released TMZ. The drug release system using micropowders and ultrasound can be applied as a drug supply system for various diseases such as brain tumors with low drug permeability.