Synthesis of Thermoresponsive Polymers for Drug Delivery
A protocol for synthesizing thermosensitive copolymers of N-isopropylacrylamide (NIPAM) and N-vinylpyrrolidone (VP), cross-linked with N,N′-methylene-bis-acrylamide (MBA) has been described in this chapter. The copolymers have been formed at different concentrations of NIPAM and VP and at two different temperatures (70 °C and 30 °C). The lower critical solution temperature (LCST) of the samples has been measured, and the size of the particles formed with the highest concentration of NIPAM and lowest concentration of VP (MG1 and NG1) has been measured at three different temperatures of 25 °C, 35 °C, and 37 °C. Both MG1 and NG1 showed the lowest size at 37 °C. The MG1 and NG1 samples were further characterized using TEM and SEM. The MG1 particles were subsequently used for protein drug delivery, using BSA as a model. The release profile showed the best fit with the zero-order model. Finally, cytotoxicity studies of the synthesized MG1 and NG1 particles were carried out, using in vitro MTT assay, so as to determine the overall biocompatibility of the materials.
Key wordsThermoresponsive N-Isopropylacrylamide Microgel Nanogel Drug delivery system Polymer cytotoxicity
This work was supported by Department of Biotechnology (DBT) New Delhi, India grant no. BT/PR8918/NNT/28/05/2007. The authors thank Swati Aerry and Mitasha Bharadwaj for this work and Dr. Y. Singh (Scientist “G”, IGIB, Delhi) for carrying out the cytotoxicity work in his lab.
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