Chitosan hydrogels were prepared by crosslinking chitosan with glutaraldehyde. The swelling behaviour of the crosslinked and uncross-linked hydrogels was measured by swelling the gels in media of different pH and at different temperatures. The swelling behavior was observed to be dependent on pH, temperature and the degree of crosslinking. The gel films were characterized by Fourier transform Infrared spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). The glass transition temperature (Tg) and the amount of free water in the hydrogels decreased with increasing crosslinking in the hydrogels.

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Blends of poly(ε‐caprolactone) (PCL) with pine resin, an extract from the plant Pinus caribaea—Hondurensis was prepared by melt mixing in mass ratios from 90/10 to 50/50. The thermal, crystallization, morphological, and mechanical properties of the blends were studied by differential scanning calorimetry, Fourier transform infrared spectroscopy, polarized optical microscopy, scanning electron microscopy, and tensile test. Enzymatic degradation of the blends was investigated using porcine pancreatic and Candida rugosa lipase. Antimicrobial activity of the blends was tested against four strains of bacteria; Staphylococcus aureas, Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa using the zone inhibition method. Miscibility of the blends was confirmed by the depression in the equilibrium melting temperature () of PCL estimated from Hoffman–Weeks plot and the presence of extinction rings in the spherulites of blended PCL. Interactions between the two components involved the carbonyl and the C‐O‐C groups. The tensile strength of the blends with low pine resin content was comparable to PCL but decreased with higher pine gum content. Enzymatic degradation of the blends increased with increasing pine resin content. The blends showed antimicrobial property with all the bacteria except E. coli. The developed biomaterial shows promising candidacy in medical applications. POLYM. ENG. SCI., 59:E32–E41, 2019. © 2018 Society of Plastics Engineers

Semi interpenetrating hydrogels (semi-IPN) of bacterial cellulose (BC) and chitosan (Ch) crosslinked with genipin were prepared and characterised using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Infrared spectra showed amide I and II absorption peaks at 1632 and 1554 cm À 1 and CÀ N stretching absorptions at 1250 and 1020 cm À 1 , respectively, for crosslinked hydrogels. The fibrous structure of BC and the porosity in the hydrogels were revealed by SEM. Swelling of hydrogels was sensitive to pH, and maximum at pH 1.0. Swelling of non-crosslinked samples decreased as the pH increased. However, with crosslinked hydrogels, swelling increased as chitosan ratio increased at low pH, as well as with increase in BC ratio at high pH. Free, bound and intermediate water types in hydrogels were revealed by DSC. The release kinetics of Quetiapine fumarate (QF), an antipsychotic drug used for the treatment of Schizophrenia was studied using UV spectrometry, followed predominantly, the Higuchi model at all pH for crosslinked hydrogels. The transport mechanism of hydrogels was a combination of non-Fickian and Super Case II. Crosslinked hydrogels showed controlled drug release behaviour. These hydrogel systems possess potential application in pharmaceutical field as all chemicals used in the development of the hydrogels are non-toxic, with BCÀ Ch 60:40 showing most promising potential.[a] J.

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