Preparation of poly(butylene succinate)‐poly[2‐(dimethylamino)ethyl methacrylate] copolymers and their applications as carriers for drug delivery

Copolymers of poly2‐(dimethylamino)ethyl methacrylate]–poly(butylene succinate)–poly2‐(dimethylamino)ethyl methacrylate] (PDMAEMA–PBS–PDMAEMA, PDBD) were synthesized through a chain‐extension reaction. The thermal properties characterized using differential scanning calorimetry showed that the introduction of PDMAEMA chains slightly decreased the melting temperature of PBS. The water contact angle of PDBD copolymer films with media of various pH decreased with a decrease of pH. This should be ascribed to the conformational transition of PDMAEMA blocks from a compact coil to an expanding shape in accordance with the variation of the pH of the surroundings. The results of dynamic light scattering and scanning electron microscopy revealed that PDBD copolymers could form spherical micelles with small particle size and narrow particle size distribution. Furthermore, drug loading (loading content, ca 10%; encapsulation efficiency, ca 60%) and release experiments were conducted using doxorubicin as a hydrophobic model drug. The results of release experiments of copolymer nanomicelles showed that these micelles had pH‐responsive properties. © 2018 Society of Chemical Industry