• biopolymers and renewable polymers;
  • blends;
  • drug delivery systems;
  • hydrophilic polymers


The objective of this article is to investigate the controlled release characteristics of 6-mercaptopurine (6-MP) loaded microspheres prepared from the blends of poly(3-hydroxybutyrate) (PHB) and Pluronic F68/127 by the oil-in-water emulsion-solvent evaporation technique. Formulations were prepared by taking different ratios of individual polymer components to achieve a maximum 79% encapsulation and extending the release time up to 24 h. Differential scanning calorimetry (DSC) suggested reduction in crystallanity of PHB after blending with Pluronic F127. The absence of chemical interactions between 6-MP and the blend matrix was confirmed by Fourier transform infrared (FTIR) spectroscopy, while the size of microspheres measured by optical microscopy ranged between 30 and 47 μm. X-ray diffraction (XRD) confirmed the crystalline nature of 6-MP even after encapsulation and surface morphology of the microspheres was investigated by scanning electron microscopy (SEM). In vitro release of 6-MP at 37°C in pH 7.4 phosphate buffer media indicated a dependence on the composition of Pluronic in the blend. The release data have been fitted to empirical equations to understand the release profile of 6-MP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40196.