Controllable biodegradation and drug release behavior of chitosan-graft-poly(D, L-lactic acid) synthesized by an efficient method

Controllable degradation is important for the biodegradable polymers used as drug carriers, because the drug release rate can be regulated by the degradation rate. Here, we synthesized chitosan-graft-poly(D, L-lactic acid) copolymers (CgPCs) with high MSPDLLA (molar substitution of poly(D, L-lactic acid)), which possessed controllable biodegradability for regulating the drug release rate. CgPCs with high MSPDLLA were prepared efficiently through an eco-friendly system of 1-ethy-3-methyimidazolium acetate (EmimAc)/4-Dimethylaminopyridine (DMAP). The MSPDLLA reached the maximum of 12.00 within 5 hours, which involved 2.91 of DSPDLLA (the degree of substitution of poly(D, L-lactic acid)) and 4.13 of DPPDLLA (the degree of polymerization of poly(D, L-lactic acid)). Importantly, the biodegradation rate of CgPCs could be regulated by the MSPDLLA. CgPCs with MSPDLLA of 3.98 showed good hydrophilicity and fast degradation leading to burst release of curcumin, whereas CgPCs with MSPDLLA of 12.00 exhibited relatively poor hydrophilicity and slower degradation resulting in sustained release of curcumin. This study provides some new possibilities for controllable biodegradation of drug carriers and optionality of burst or sustained drug release. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Controlled degradation is crucial for biodegradable polymers used as drug carriers in order to regulate drug release rate. In this study, chitosan-graft-poly(D, L-lactic acid) copolymers with high MSPDLLA were synthesized, showing controllable biodegradability for drug release rate modulation. The results revealed that the biodegradation rate of CgPCs could be regulated by MSPDLLA, leading to burst or sustained release of drugs depending on the MSPDLLA value.