Synthesis and characterization of novel polyorganophosphazenes substituted with 4-methoxybenzylamine and 4-methoxyphenethylamine for in vitro release of indomethacin and 5-fluorouracil

Two novel organopolyphosphazenes viz., poly[bis(4-methoxy benzylamino)polyphosphazene] (POP-1) and poly[bis(4-methoxyphenethylamino)polyphosphazene] (POP-2) have been synthesized by replacing chlorine atoms of polydichlorophosphazene with 4-methoxybenzylamine and 4-methoxyphenethylamine. These polymers have been characterized by FTIR, 1H, 13C and 31P NMR. Polymers prepared have been subjected to DSC and TGA analysis to determine their glass transition temperature and thermal stability. Microspheres have been prepared by incorporating indomethacin (water insoluble) and 5-fluorouracil (water soluble) drugs. In vitro release characteristics of indomethacin was performed in 7.4 pH media, while for 5-fluorouracil, release studies were performed in both pH 7.4 and 1.2 buffer media. The % cumulative release of indomethacin increased with increasing drug loading. Sustained release was achieved at lower loadings of indomethacin, but for 5-fluorouracil, release was achieved in pH 1.2 media and the release was fast in pH 7.4 buffer media.