A systematic study on the influence of lactic acid (LA) conformation on polyester properties, degradation, and drug release profiles is reported. Copolyesters based on L- or DL-LA and castor oil (CO) (triglyceride of ricinoleic acid (RA)) were synthesized by melt condensation. Two feed ratios of LA to CO were used. Copolymers with feed ratio of 60:40 and 50:50 LA to CO were synthesized. P(LA/CO)s 60:40 and 50:50 had weight average molecular weights (Mw) of 4700 and 3700, respectively. All polymers are viscous liquids at room temperature. Copolymer composition and LA conformation had direct effect on polymer properties, degradation rate, and drug release profile. Increase in CO content (hydrophobisity) decreased the degradation and release rates of the polymers. Effect of sample size was also different for all polymers. Choosing polymer composition and LA conformation it is possible to choose desired release profile for the tested drug.
- Drug delivery systems
- Structure-property relations