A keratinase isolated from Paecilomyces lilacinus (LPS #876) was tested against proteins present in the skin but the high enzyme activity was detected on collagen. Keratinase was physically immobilized onto PVA-pectin cryogels and enzyme release was 20.8 +/- 2.1%, 63.8 +/- 0.2%, 41.5 +/- 3.5% and 26.0 +/- 3.5% in cryogels containing pectins with esterification degrees (DE) 33.0%, 55.0%, 62.7% and 71.7% respectively at 37 degrees C after 3 h incubation. In presence of 0.75 M NaCl, the percentage of enzyme release changed to: 57.5 +/- 1.5, 65.8 +/- 3.8, 57.3 +/- 0.2 and 34.0 +/- 4.0 for the four pectins respectively. In-vitro studies of enrofloxacin release from PVA-pectin cryogels at pH close to the human skin (pH = 5.5) showed 15.0% free antibiotic following first order kinetic at 37 degrees C after 5 h incubation. However, in the presence of keratinase only 6.9% of enrofloxacin was released under the same experimental conditions. (C) 2013 Elsevier Ltd. All rights reserved.