Prednisolone-loaded albumin nanospheres: in vitro and in vivo evaluation studies

Prednisolone-loaded bovine serum albumin (BSA) nanospheres prepared by pH-coacervation were evaluated regarding recovery, drug entrapment efficiency, particle size, shape, surface morphology, in vitro drug release profile, and in vivo distribution. The method of analysis was validated in terms of accuracy, precision, and repeatability. No significant change in the drug's chemical integrity was observed when incorporated in the nanospheres. It was observed that the average particle size and drug entrapment efficiency of the nanospheres increased with the increase in drug loading. All the batches exhibited biphasic drug release with an initial burst effect followed by gradual steady release. The higher the drug loading, the greater was the burst effect. The mechanism of prednisolone release from the nanospheres was found to be due to diffusion and erosion as observed by fitting the release data in different models. The drug's in vivo distribution was found to be highest in the liver followed by the spleen and lungs. Stability studies indicated that nanosphere formulations should be stored at 4 +/- 2 degrees C.