The incorporation and release of bovine serum albumin from poly-hydroxybutyrate-hydroxyvalerate microcapsules

Spherical microporous reservoir type microcapsules composed of P(HB-HV) (10.8% HV)/20% PCL containing BSA (surrogate protein) loaded agarose have been fabricated using a double emulsion technique with solvent evaporation. Microcapsules were generated in high yield (> 75 wt%) and BSA incorporation had no significant effect on microcapsule size distribution (21-200 microns). The loss of BSA both by partitioning into the aqueous continuous phase, and through micropores as BSA-loaded-agarose during the precipitation of the fabrication polymer concomitant with solvent evaporation, resulted in low encapsulation efficiency (12%). The amount and duration of BSA release was influenced as much by micropore numbers and diameter as by the extent of reservoir loading and detectable levels of BSA release could be monitored for up to 24 days.