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 13 C 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.

The main aim of the present investigation is synthesis of drug-grafted poly(vinyl alcohol) (PVA) for sustainable drug release in order to avoid bulk release and unwanted side effects. Here, the PVA was structurally modified with five different drug molecules in DMSO medium at 85 8C under N 2 atmosphere for 2 h. The structure of modified PVA was confirmed by FTIR and 1 H NMR spectra and further it was characterized by TGA, DSC, and SEM. The tensile strength and % elongation for the structurally modified PVA were determined. The FTIR spectrum showed peaks corresponding to the C@O and CAS stretching due to the grafted drug molecules. The 1 H NMR spectrum showed the acrylic CH 2 proton signal of PVA around 1.6 ppm. The SEM showed different surface morphology for the structurally modified PVA. The mechanical properties of the structurally modified PVA was found to be reduced due to the presence of traces of solvent molecules and the breaking of inter-and intramolecular hydrogen bonding. The sustainable drug release through hydrolysis mechanism was tested at the pH of 7.3. Generally, the drug release followed the Korsmeyer-Peppas model with Fickian drug transportation mechanism except Furosemide (Fur)-grafted PVA system at the pH of 7.3. V C 2018Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46620.