Novel bioresorbable and bioeliminable surfactants for microsphere preparation

Purpose. The objective of this work is to prepare microspheres by the emuls ion-solvent evaporation process using MPOE-PLA copolymers as the matrix mat erial and/or the surfactant. This preparation was studied in order to avoid the use of PVA as the surfactant in the process. Methods. Two series of MPOE-PLA copolymers were synthesised. The first, wit h a long and constant length PLA chain (45,000 g.mol(-1)), was used as the matrix material, the second, with short PLA chains (less than or equal to 2 ,200 g.mol(-1)), and different HLB as the surfactant. Microspheres were pre pared by the "simple" and "double" emulsion methods. The steric stabilizati on effect of the copolymers was investigated using confocal microscopy and X-ray photoelectron spectroscopy (XPS). Results, Confocal microscopy and XPS analysis showed that the microspheres prepared using MPOE5K-PLA0.5K as the surfactant and MPOE-PLA45K copolymers as the matrix material had an MPOE coating present at the microsphere surfa ce. This hydrophilic layer ensures steric stabilization of the particles. Conclusions. MPOE-PLA copolymers can be used for the preparation of particl es instead of PVA and their use can be extended whenever a biocompatible an d bioeliminable surfactant is required for biological or medical applicatio ns.