Studies on Properties and Drug Delivery Systems of PTMC-b-PEG-b-PTMC Block Copolymers

ABA type block copolymers of poly(trimethylene carbonate) with poly(ethylene glycol) were synthesized and characterized. The dynamic contact angle of PTMC-b-PGG-b-PTMC(PTPEPT) block copolymer film was determined. It revealed that the acceding angle (θ a ), decreased with the increase of PEG content in copolymers, indicating that the PEG fractions lead to higher hydrophilicity of PTPEPT copolymers. The potential application of PTPEPT copolymers for drug delivery systems was investigated. The measurement of drug delivery using PTPEPT as matrices showed that the release rate of Levonorgestrel (LNG) increased with the increase of hydrophilicity of copolymer samples. No obvious burst effect of release of LNG could be observed in the LNG/PTPEPT systems especially when the PTMC block became longer. In a short period, about 25 days, the release rate of LNG remained almost constant.