Modified Poly(T-Butyl Methacrylate) as a Doxorubicin Carrier for Targeted Delivery

Abstract

Poly(t-butyl methacrylate) (PTBMA) was selected as a doxorubicin carrier for targeted delivery because it can hydrolyze to form water-soluble polymers. A chain-transfer reaction with thioglycolic acid was used. The thioglycolic acid concentration was 1 mass%, at which a polymer with the optimal biocompatibility (molecular mass ~12 kDa, polydispersion index M_w/M_n ≈ 1.5) was obtained. The polymer was chemically modified by a folate vector. The resulting polymer was converted via acid hydrolysis into a water-soluble copolymer. Then, a conjugate of doxorubicin (DOX) with the copolymer of t-butyl methacrylate and methacrylic acid modified by the folate vector on the terminal carboxylates was prepared. The degree of DOX conjugation to the polymer was 62.7 ± 11.8%. DOX was released from the polymer system almost three times faster at pH 4.6 than at pH 7.4. The cytotoxicity of the polymer conjugate was 1.52 μM.