Albumin release from bioerodible hydrogels based on semi-interpenetrating polymer networks composed of poly(ε-caprolactone) and poly(ethylene glycol) macromer

Poly(ethylene glycol) (PEG) macromers terminated with acrylate groups and semi-interpenetrating polymer networks (SIPNs) composed of poly(epsilon-caprolactone)(PCL) and PEG macromer were synthesized and characterized to obtain a bioerodible hydrogel that can be used for albumin delivery. Polymerization of PEG macromer resulted in the formation of cross-linked gels due to the multifunctionality of macromer. Glass transition temperature (T-g) and melting temperature (T-m) of PEG network and PCL in the SIPNs were inner-shifted, indicating an interpenetration of PCL and PEG chains. Water content in the SIPNs increased with increasing PEG weight fraction due to the hydrophilicity of PEG. The amount of albumin released from the SIPNs increased with higher PEG content in the SIPNs, higher drug loading, lower concentration of PEG macromer during the SIPNs preparation, and the higher molecular weight of PEG. The degradation rate of the SIPNs gels in vitro increased with increasing of PEG weight fraction. (C) 1997 Elsevier Science B.V.