pH triggered doxorubicin delivery of PEGylated glycolipid conjugate micelles for tumor targeting therapy.

The main objective of this study was aimed at tumor microenvironment-responsive vesicle for targeting delivery of the anticancer drug, doxorubicin (DOX). A glucolipid-like conjugate (CS) was synthesized by the chemical reaction between chitosan and stearic acid, and polyethylene glycol (PEG) was then conjugated with CS via a pH-responsive cis-aconityl linkage to produce acid-sensitive PEGylated CS conjugates (PCCS). The conjugates with a critical micelle concentration (CMC) of 181.8 μg/mL could form micelles in aqueous phase, and presented excellent DOX loading capacity with a drug encapsulation efficiency up to 87.6%. Moreover, the PCCS micelles showed a weakly acid-triggered PEG cleavage manner. In vitro drug release from DOX-loaded PCCS micelles indicated a relatively faster DOX release in weakly acidic environments (pH 5.0 and 6.5). The CS micelles had excellent cellular uptake ability, which could be significantly reduced by the PEGylation. However, the cellular uptake ability of PCCS was enhanced comparing with insensitive PEGylated CS (PCS) micelles in weakly acidic condition imitating tumor tissue. Taking PCS micelles as a comparative group, the PCCS drug delivery system was demonstrated to show much more accumulation in tumor tissue, followed by a relatively better performance in antitumor activity together with a security benefit on xenograft tumor model.