Lipase-catalyzed alpha-butylglucoside lactate synthesis in organic solventfor dermo-cosmetic application

alpha-Butylglucoside can be used as a vector for lactic acid: alpha-butylgl ucoside lactate synthesis can be achieved through transesterification catal yzed by immobilized Candida antarctica lipase. Synthesis was performed in a n inert tertiary alcohol, 2-methyl-2-butanol. The reaction rapidly reached a thermodynamic equilibrium which could be shifted towards synthesis by alc ohol product removal under reduced pressure: more than 95% of alpha-butylgl ucoside could be converted. However, the denaturating effect of lactate don or polar species affected lipase stability. A fed-batch process proved to b e the most interesting method because it enables both high alpha-butylgluco side lactate concentrations to be obtained (similar to 150 g l(-1)) and lip ase to be better protected from denaturation. Irritation tests on model ski n and on butchered beef cornea finally showed the value of alpha-butylgluco side lactate as a lactic acid vector, offering the cosmetic benefits of the alpha-hydroxy acid but also eliminating the adverse effect of the free aci d. (C) 1999 Elsevier Science B.V. All rights reserved.