title: Swelling behaviour of pH-sensitive crosslinked poly(vinyl acetate co-acrylic acid) hydrogels for site specific drug delivery.
abstract: The present work was undertaken to combine nonionic vinyl acetate (VAC) with anionic acrylic acid (AA) or methacrylic acid (MAA) monomers in the presence of ethylen glycol dimethacrylate (EGDMA) as cross-linking agent through radical polymerization. Poly(vinyl acetate-co-acrylic acid) VAC/AA 50:50 to 100:0 six samples and poly(vinyl acetate-co-methacrylic acid) VAC/MAA one sample were prepared. All the samples were used for swelling studies. High swelling occurred at above pH 5.5 through chain relaxation. It was observed that swelling in VAC/MAA was lower than VAC/AA copolymers. The lower swelling in VAC/MAA copolymer is due to the presence of hydrophobic methyl group and higher pKa value of this copolymer.
authors.affiliation: Department of Pharmacy Bahauddin, Zakariya University, Multan, 60800, Pakistan.
authors.forename: N M
authors.initials: NM
authors.lastname: Ranjha