Dual-drug delivery system based on hydrogel/micelle composites.

We present a dual-drug delivery system (DDDS) of hydrogel/polypeptide micelle composites in this work. The DDDS was constructed from aspirin (Asp) dispersed poly(vinyl alcohol) (PVA) or Chitosan (CS)/PVA hydrogel and doxorubicin (DOX) loaded poly(L-glutamic acid)-b-poly(propylene oxide)-b-poly(L-glutamic acid) (GPG) micelles. Independent release behaviors of the two drugs are observed. Asp has a short-term release while DOX has a long-term and sustained release behavior in all the DDDSs. The release of DOX from all the DDDSs is environmentally controlled due to the pH and temperature sensitivity of the GPG micelle. Asp shows the pH controlled release behavior in CS/PVA/micelle DDDS due to the pH sensitivity of CS hydrogel. The releasing profiles were analyzed using a power law equation proposed by Peppas. It reveals that the release of Asp is anomalous transport in all the hydrogel/micelle DDDSs. The release of DOX is Fickian type in PVA/micelle system, and changes to anomalous transport in CS/PVA/micelle system according to the release exponent n.