Several segmented polyurethanes comprising azo aromatic and hydrophilic groups were synthesized by reaction of m-xylylene diisocyanate with a mixture of m,m'-dihydroxyazobenzene, poly(ethylene glycol) (PEG, M, = 2000) and 1,2-propanediol (propylene glycol, PG). Their polymer films were made by solution casting, and pellets of a hydrophilic drug (FOY-305) were coated with these polymers. Both the films and the coated pellets were incubated anaerobically in a culture of human intestinal flora. It was found that the azo groups in the polymer were reduced to hydrazo groups during incubation, which induced degradation of the films and the coatings without decreasing the molecular weight of the polymer. The rate of drug release from the pellets depended on both the azo and PEG compositions. Based on these findings, a new degradation mechanism of the polyurethane films and coatings is proposed.
Посилання на статтю:
Degradation of azo-containing polyurethane by the action of intestinal flora: its mechanism and application as a drug delivery system / Y. Kimura*, Y. Makita, T. Kumagai, H. Yamane and T. Kitao // Polymer. – 1992. – Vol 33. – P. 5294-5299.
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