Novel biodegradable polyphosphazenes containing glycine ethyl ester and benzyl ester of amino acethydroxamic acid as cosubstituents : Syntheses, characterization, and degradation properties
✍ Scribed by L. Y. Qiu; K. J. Zhu
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 188 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0021-8995
No coin nor oath required. For personal study only.
✦ Synopsis
Novel biodegradable polyphosphazenes containing glycine ethyl ester and benzyl ester of amino acethydroxamic acid as cosubstituents (PGBP) were synthesized by further modifying poly[bis(glycine ethyl ester)phosphazene] (PGP). The polymers were characterized by IR, 1 H-NMR, DSC, and elemental analysis. Degradation experiments were conducted in vitro at varied pH conditions. The results indicated that the degradation of PGBP was pH-sensitive. The sample dissoluted after 1.5 days under a physiological condition (pH 7.4) but took more than 20 days under an acidic condition (pH 5-6), which was related to the content of the benzyl ester of amino acethydroxamic acid in the polymer. The "two-stage" degradation mechanism of PGBP was proposed: that the polymer first degraded to a water-soluble polymeric product with the fast break of side groups, followed by the relatively slow scission of the backbone. This property of PGBP may be useful in controlled drug-delivery systems.