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Chitosan/gelatin and chitosan/gelatin/zeolite films prepared by solvent casting method are impregnated with a mixture of thymol and carvacrol using a green solvent, supercritical carbon dioxide at 35 °C and 30 MPa, during 18 h. Proposed method enables preparation of biocompatible and biodegradable blends with strong antioxidant and antibacterial activity, whereby amounts of loaded thymol/carvacrol (TC) mixture are in the range from 3.3% to 6%. After initial burst release, both types of films exhibit gradual release of bioactive compounds, with around 72% and 96% of impregnated TC mixture released in water and phosphate buffered saline solution (pH 7.4) during tested period of 10 days, respectively. Results of water vapor transmission rate (>76 g m−2 day−1) confirm that prepared composites are suitable for wound dressing application. Thermal analysis shows superior properties of prepared TC loaded films compared to control samples. In addition, mechanical and structural properties, as well as solubility and swelling behavior of the obtained films are investigated in detail. [ABSTRACT FROM AUTHOR]

Outbreak of surgical infections and bacterial resistance against synthetic antibiotic has prompted research towards development of antibacterial medical devices. For that purpose, absorbable surgical sutures were impregnated with natural compound thymol using an environmentally friendly medium. The supercritical solvent impregnation process was performed at 35 °C and 10 MPa during 1, 2, 3 and 6 h, resulting in thymol loadings of 3.9–5.6%. All tested samples expressed antibacterial activity against E. coli and S. aureus. Release tests in PBS at 37 °C showed that impregnated material released loaded thymol in a gradual manner. While sutures impregnated during 6 h released complete amount of loaded thymol during 6 days, shorter impregnation process resulted in sutures that retained significant thymol amounts (~ 20–40%) after 10 days of release test. The effect of proposed process on final material properties and its application were explained in detail using characterization techniques SEM, FTIR, DSC and DMA. [Display omitted] • SSI process enabled preparation of surgical sutures effective against E. coli and S. aureus. • Mild process conditions (35 °C, 10 MPa, 1–6 h) allowed thymol loadings up to 5.9%. • Impregnated sutures released thymol in a controlled manner during 10 days. • Mechanical properties of sutures were negligible affected by the proposed SSI process. [ABSTRACT FROM AUTHOR]