Synthesis and in vitro degradation studies of substituted poly(organophosphazenes) for drug delivery applications

The synthesis, characterization and in vitro degradation studies of controlled molecular weight degradable poly(organophosphazenes) bearing various hydrophilic and hydrophobic side group is reported. The polymerization was carried out by thermal polymerization of cyclic trimer hexachlorocyclotriphosphazene at 260 +/- 5 degrees C for 4-5 h to yield poly(dichlorophosphazene). This polymer backbone was suitably substituted with sodium or potassium salts of dlcoholic or phenolic compounds and ethyl 4-aminobenzoate to obtain substituted poly(organophosphazenes). The characterization of polymers was carried out by IR, H-1 NMR and P-31 NMR. The molecular weights of these novel polyphosphazenes were determined using size exclusion chromatography with a Waters 515 HPLC Pump and a Waters 2414 refractive index detector. The degradation behavior was studied by 200 mg pellets of polymers in phosphate buffers pH 5.5, 6.8 and 7.4 at 37 degrees C. These polymers exhibited hydrolytic degradability, which cab afford applications to a variety of drug delivery systems. This study shows that poly(organo)phosphazenes could be a potential novel class of biodegradable polymeric carriers for targeted drug delivery. (C) 2017 Elsevier B.V. All rights reserved.