Narrow Results

This study investigates in vitro the protein drug delivery characteristics of new thermal sensitive gels, poloxamer (P)–chitosan (CS)/hyaluronic acid (HA) gels (P–CS/HA), in which a CS solution is interacting with various concentrations of HA that interpenetrates P gels. The polyion complexation occurs between CS and HA that can protect drugs from proteolysis. The results indicate that the swelling ratios of all P–CS/HA gels are markedly superior to those of nonswelling P and P–CS gels. For example, P–CS/HA (0.5% (w/w)) gels have swelling ratios of 48.3 ± 2.7% (w/w), which are maintained for approximately 0.5 h in water at 37°C. In vitro releases of insulin from P–CS/HA (0.5% (w/w)) gels had significantly lowered initial burst release (P < 0.01) and lasted much longer than those from gels without a CS network. The duration of insulin release was in a significantly sustained manner for up to 3.5 h, which was about two times or longer than the period of delivery using P or P–CS gels.