Hydrolysis of Racemic Ibuprofen n-Octyl Ester Catalyzed by Lipase in Cetyl Trimethyl Ammonium Bromide/p-Octyl Polyethylene Glycol Phenyl Ether Microemulsion-based Gel

Abstract

A preliminary study was performed on the main influence factors of the hydrolysis of racemic ibuprofen n-octyl ester catalyzed by lipase immobilized in cetyl trimethyl ammonium bromide( CTAB) /p-octyl polyethylene glycol phenyl ether( TX-100) microemulsion-based gel( MBG). The lipase immobilized in CTAB /TX-100 MBG could smoothly catalyze the hydrolysis of S-ibuprofen n-octyl ester to S-ibuprofen in aqueous solution. As the content of TX-100 in EM( the mixture of n-butanol and TX-100) increased gradually,the reaction conversion( X) always increased correspondingly,but the enantiomeric excess of produced S-ibuprofen( eei) decreased slightly. The curve of X vs eeiall showed bell shape with the content of water in MBG increasing and the optimum water content of MBG was 27. 3%. The influence of phosphate buffer on X and eeiwas generally greater than that of water dissolving gelatin. X increased significantly in the early reaction stage( before 16 h) and then increased slowly till 24 h and didn't change any more even though the reaction was prolonged,but the eeidecreased slightly in whoe reaction process. No significant change on X was observed in the first 3 recycle of immobilized lipase,but X decreased obviously in the following recycles. The eeialso decreased as the recycle times increased. After 10 reusage,X and the eeidecreased by 36. 55% and0. 52%,respectively.