The antioxidant enzyme catalase (CAT) was encapsulated in biocompatible flexible non-ionic sugar esters (SEs) nano-vesicles for potential topical administration. The effects of the SE hydrophilic lipophilic balance (HLB) value and the carbon chain length of the fatty acid ester of different SEs on the encapsulation efficiency (EE) were studied. Morphology of the vesicles was not altered upon CAT encapsulation using freeze fracture electron microscopy. The extrusion measurements indicated that there was an increase in the vesicle's flexibility index upon the inclusion of phospholipids. The mean diameter of the CAT-EV (ester vesicle; HSC and HSC-PL) was 222-275 nm using laser diffraction measurements. The catalytic efficiency (V-max/K-m) of CAT was improved after encapsulation by a factor of 1.7. Both free CAT and CAT-EV showed maximum catalytic activity at pH 7.0. and CAT-EV was more stable than free CAT at acidic pH. which is advantageous for successful topical delivery. Encapsulation of CAT in SE vesicles protected it against trypsin treatment. Encapsulated CAT retained more than 60% residual activity after 12 successive decomposition cycles of H2O2. CAT-EV activity was significantly preserved compared to that of free CAT at 4 degrees C for 180 days. The in vivo study showed a significant effect of the prepared CAT nano-vesicles on wound healing. (c) 2012 Elsevier Ltd. All rights reserved.