Synthesis and characterization of some organopolyphosphazenes and their controlled-release characteristics

Two new organopolyphosphazenes, viz., poly[bis(3-methoxy benzyloxy) phosphazene] (POP-1) and poly[bis(4-fluoro-4′-oxybenzophenone)]phosphazene (POP-2), have been prepared by replacing chlorine atoms of dichloropolyphosphazene with 3-methoxy benzylalcohol and 4-fluoro-4′-hydroxy-benzophenone. The polymers have been characterized by Fourier tranform infrared spectroscopy (FT-IR), 1H- and 31P-nuclear magnetic resonance (NMR) spectra and thermogravimetric (TGA) analyses. The polymers have been developed as microspheres to study their controlled-release characteristics for indomethacin, an anti-inflammatory drug. Drug-loaded microspheres have been tested for in vitro release in pH 7.4 buffer media. FT-IR, 1H- and 31P-NMR data confirmed the formation of polyorganophosphazenes substituted with 3-methoxy benzylalcohol and 4-fluoro-4′-hydroxy-benzophenone. In vitro drug-release studies have indicated sustained and controlled release of indomethacin through POP microspheres.