Biodegradable polymer phosphoesters

Biodegradable poly(phosphoester-urethanes) containing bisglycophosphite as the chain extender were synthesized. Methylene bis-4-phenyl isocyanate (MDI) and toluene diisocyanate (TDI) were initially used as diisocyanates. Since there was a concern that the degradation products could be toxic, the ethyl 2,6-diisocyanatohexanoate (LDI) was synthesized and replaced the MDI (or TDI). The hydrolytic stability and solubility of these polymers were tested. Preliminary release studies of 5-fluorouracil from MDI based poly(phosphoester-urethane) and methotrexate from LDI based poly(phosphoester-urethane) are also reported. 

Our interest in the past few years has been on biodegradable polymers. We have been evaluating the potential of poly(phosphoesters) as degradable biomaterials (4).We were attracted to this class of polymers because the phosphoester bond in the backbone is cleavable under physiological conditions, the presence of the P-O-C group would facilitate fabrication, and the versatile chemical structure affords a wide... 

Mao H-Q, Kadivala I, Leong KW, Zhao Z, Dang W. Biodegradable polymers poly (phosphoester)s. In Mathiowitz E, ed. The Encyclopedia of Controlled Release. New York Wiley, 1999 45-60. 

Poly(alkylene H-phosphonate)s represent a wide range of biodegradable polymers with repeating phosphoester linkages in the backbone and have been inserted in a variety of complex macromolecular architectures (Scheme 6.17). 

The biodegradabUity of the polymer is due primarily to the physiologically labile phosphoester bond in the backbone of the pol5mier. By manipulating the backbone or the side chain, a wide range of biodegradation rates are attainable. 

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