Preparation of thermoresponsive core-shell copolymer latex with potential use in drug targeting

A core-shell copolymer latex with thermal-responsive properties was prepared and its potential application as a vehicle for drug targeting was investigated in this work, where the crosslinked copolymer of N-isopropylacrylamide (NIPAAm) and chitosan was prepared as the core and the copolymer of methacrylic acid (MAA) and methyl methacrylate (MMA) was prepared as the shell. By using soapless dispersion polymerization, the poly(NIPAAm-chitosan) crosslinked copolymer latex was synthesized first. Then the monomers of MAA and MMA were added to continue the reaction to obtain the core-shell copolymer latex. The weight ratio of MAA/MMA and the concentration of shell monomers (MAA and MMA) in the feed of the reaction mixture had been changed to investigate their effects on the particle size, reaction rate, zeta-potential, specific surface area, and surface functional groups of the latex particles. The swelling and thermoresponsive behavior of the film made from these core-shell latices were also studied under different pH values of buffer solution. The model drug (caffeine) could be merged inside the copolymer particles and protected from releasing through the transport process effectively. And the thermoresponsive property of these copolymer particles significantly enhances the ligand (protein) conjugation that shows the potential of the latex being applied on the targeting drug carrier.