Title: Application of lipases immobilized on Octyl-Sepharose CL-4B carrier as potential biocatalysts in obtaining pure enantiomers of NSAIDs

Abstract

Lipases are enzymes belonging to acylglycerol hydrolases (EC 3.1.1.3). Their catalytic activity is manifested, among others, by the hydrolysis of triglyceride ester bonds in an aqueous medium and the reactions of esterification or transesterification in a nonaqueous medium. Lipases are widely used in the chemical and pharmaceutical industries and for these purposes, they are often immobilized. This process consists of immobilizing the enzyme on support, aiming to increase its activity, stability and to enable its recovery. The area of lipase application is often kinetic resolution of racemic mixtures of drugs or compounds, which are building blocks in the reactions of obtaining drug enantiomers. Lipase from Candida rugosa (CRL) has a "lid" in its structure, while lipase B from Candida antarctica (CALB) is characterized by its absence. Moreover, in the kinetic resolution of racemates, CRL is directed to carry out the esterification of the S enantiomer, and CALB shows enantioselectivity toward the R enantiomer. The aim of this study was to optimize the catalytic systems to obtain pure enantiomers of (R,S)-flurbiprofen by esterification with methanol in organic solvents differing in the logP value. It was the first time, lipases immobilized on Octyl-Sepharose CL-4B have catalyzed the kinetic resolution of racemate by esterification in organic solvents with a good yield and enantioselectivity. Studies have shown that CALB has high enantioselectivity (eep = 90.48%) when the kinetic resolution of (R,S)-flurbiprofen is performed in dichloromethane, characterized by a low logP value. In contrast to CALB, CRL catalyzed the reaction to a very small extent. Comparing the activity of the free form and that of the immobilized CALB, it was proved that immobilization on the Octyl-Sepharose CL-4B support increased the activity of the tested lipase by about 12 times in dichloromethane and about 45 times in dichloroethane. Moreover, it was observed that the choice of the reactor with regard to the material from which it is made is important.