Preparation of magnetic poly(lactic‐co‐glycolic acid) microspheres with a controllable particle size based on a composite emulsion and their release properties for curcumin loading

Abstract

ABSTRACTBecause of their unique magnetic features and good biocompatibility, magnetic poly(lactic‐co‐glycolic) acid (PLGA) microspheres have great application potential in magnetic targeted drug‐delivery systems. In this research, magnetic PLGA microspheres with controllable particle sizes were successfully prepared from a composite emulsion with a T‐shaped microchannel reactor. A water‐in‐oil‐in‐water composite emulsion was generated by the injection of a dichloromethane/gelatin water‐in‐oil initial emulsion into the microchannel together with a coating aqueous phase, that is, the aqueous solution of glucose and poly(vinyl alcohol). The mean particle size of the microspheres could be controlled by the manipulation of the osmotic pressure difference between the internal and external aqueous phases via changes in the glucose concentration. Curcumin, a drug with an inhibitory effect on tumor cells, was used to exemplify the release properties of the magnetic PLGA microspheres. We found that the mean particle size of the microspheres ranged from 16 to 207 μm with glucose concentrations from 0 to 20 wt %. The resulting microspheres showed a rapid magnetic response, good superparamagnetism, and a considerable magnetocaloric effect, with a maximum magnetic entropy of 0.061 J·kg−1·K−1 at 325 K. An encapsulation efficiency of up to 77.9% was achieved at a loading ratio of 3.2% curcumin. A release ratio of 72.4% curcumin from the magnetic PLGA microspheres was achieved within 120 h in a phosphate‐buffered solution. The magnetic PLGA microspheres showed potential to be used as drug carriers for magnetic targeted tumor therapy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43317.