Preparation of thermo/redox/pH-stimulative poly(N-isopropylacrylamide-co-N,N'-dimethylaminoethyl methacrylate) nanogels and their DOX release behaviors.

Stimuli-sensitive drug delivery systems show beneficial features of both medical and pharmaceutical fields. In this article, polymeric nanogel P (N-isopropylacrylamide-N,N '-dimethylaminoethyl methacrylate [NIPAM-DMAEMA]) (PND) with pH/redox/thermo-responsivenesses was synthesized by the in situ polymerization of NIPAM and DMAEMA for the controlled release of doxorubicin hydrochloride (DOX) and N,N '-bis(acryloyl)cystamine (BAC) and N,N '-methylenebisacrylamide (MBA) act as the crosslinkers, respectively. The structure, size, and zeta potential of PND-BAC and PND-MBA were further characterized. Moreover, after loading DOX, the encapsulation efficiency and the in vitro release behavior of PND-BAC/DOX and PND-MBA/DOX nanogels were discussed in detail. Compared to PND-MBA NGs, PND-BAC nanogels have redox degradability due to the presence of the crosslinker BAC. After loading DOX, the PND-BAC/DOX nanogel showed a higher encapsulation efficiency (81.6 ± 1.2)% and thermo- and pH-responsiveness as well as redox-responsive in vitro release. These properties together with excellent environmentally sensitive properties make PND-BAC as an attractive candidate for application in drug nanocarriers for the targeted drug delivery of model payloads. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1195-1203, 2019.