The effect of crosslinking agent on sustained release of bFGF-collagen microspheres

Initial burst release and loss of bioactivity of drugs are the shortcomings of drug delivery systems (DDSs) used for in vivo treatment. Therefore, in this context, hydrophilic collagen was chosen as the carrier material for basic fibroblast growth factor (bFGF) and collagen microspheres were crosslinked by carbodiimide (EDC) in different concentrations. Collagen microspheres were characterized by a mastersizer, scanning electron microscope (SEM), differential scanning calorimetry (DSC) analysis, determination of free amino test and methyltetrazolium (MTT) test due to reveal their particle size and distribution, surface morphology, thermodynamic properties, crosslinking degree and biocompatibility. The effect of crosslinking agent on the release kinetics of bFGF-collagen microspheres was studied systematically in detail. The results demonstrate that the crosslinking agent concentration has some influence on the release of collagen microspheres and has the potential to reduce initial drug burst release and control the release rate. This study provides an opportunity for preparing bFGF-collagen microspheres for application in the DDS field.