Thermo-sensitivity and triggered drug release of polysaccharide nanogels derived from pullulan-g-poly(L-lactide) copolymers

Thermo-responsive nanogels from poly(L-lactide)-g-pullulan (PLP1 and 2) copolymers with different lactide contents were investigated as an anticancer drug delivery carrier. The phase transition temperature of PLP 1 with lower lactide content in distilled water showed around 35 degrees C. Upon adding 0.15 M NaCl to PLP 1, a significant difference in the transmittance was observed when comparing the non-additive salt condition. The total amount of released doxorubicin (DOX) from the DOX-loaded PLP nanogels increased with increasing temperature for 50 h. A noticeable difference in the initial release by PLP 1 was observed between 37 and 42 degrees C. In the 50% inhibitory concentration (IC(50)) analysis, the IC(50) values of DOX released from PLP 1 were approximately 5.9 and 9.3 mu g/mL at 37 and 42 degrees C. respectively. The results suggest that self-assembled PLP nanogels, by means of a triggering temperature, can be used as a long-term drug delivery system in cancer treatments. (C) 2011 Elsevier Ltd. All rights reserved.