Characterization of novel soybean-oil-based thermosensitive amphiphilic polymers for drug delivery applications

Hydrolyzed polymers of soybean oil (HPSO) and of epoxidized soybean oil (HPESO) were developed previously. Owing to their natural food origin and biocompatibility, we exploited further their potential as a drug delivery system and pharmaceutical excipients. This work aimed to investigate self-assembly, thermal transition, interaction with various drugs and surface activity of these novel amphiphilic polymers. The critical micelle concentration of HPSO and HPESO was determined by the surface tension method. The molecular interaction between HPESO and anticancer drug doxorubicin HCl was examined. The effect of the polymers on the solution contact angle and surface energy of compressed tablets of hydrophobic drugs ibuprofen and nifedipine was measured. The thermal transition temperatures Ttr (cloud points) of the polymers in aqueous solutions increased with increasing polymer concentration. HPSO exhibited lower Ttr than HPESO. The critical micelle concentration was found to be 0.05 mg mL-1 for HPSO and 0.08 mg mL-1 for HPESO. Strong molecular interactions between HPESO and doxorubicin were observed. Both polymers reduced the interfacial energy and contact angles of drug tablets with more effect on ibuprofen tablets with the use of HPSO. These results suggest that the novel soybean-oil-based amphiphilic polymers have great potential for drug delivery and pharmaceutical formulations. Copyright (c) 2012 Society of Chemical Industry