Synthesis, characterization and drug-delivery activity of rifampin anchored poly(vinyl alcohol)

Poly(vinyl alcohol) (PVA) has wide applications in film industries owing to the hydrophilicity and biocompatibility. In recent times the application of PVA is extended to drug-delivery field. Unfortunately, the thermal stability of PVA is very poor. In order to increase the thermal stability, the drugs were chemically conjugated with PVA. In the present investigation rifampin (Rif.) a bactericidal antibiotic drug was chemically conjugated with PVA backbone. The resultant Rif.-conjugated PVA was characterized by Fourier transform infrared spectroscopy, UV-visible spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry, and thermogravimetric analysis (TGA). Finally, the Rif.-conjugated PVA was tested for the drug-release activity. The scanning electron microscope morphology declared the presence of microvoids on the surface of PVA and the same was effectively used for the drug-loading purpose. Mechanical properties of PVA before and after the structural modification process were also tested. The aromatic carbon signal around 120-150 ppm in the C-13 NMR confirmed the chemical grafting of Rif. on to the PVA backbone. The TGA confirmed the four-step degradation process for the structurally modified PVA.