A facile enzymatic process for the preparation of (s)-Naproxen ester prodrug in organic solvents

Process modeling of the lipase-catalyzed dynamic kinetic resolution of (R, S)-suprofen 2,2,2-trifluoroethyl thioester in a hollow-fiber membrane

A Candida rugosa lipase immobilized on polypropylene powder was employed as the biocatalyst for the enantioselective hydrolysis of (R, S)-suprofen 2,2,2-trifluorothioester in cyclohexane, in which trioctylamine was added as the catalyst to perform in situ racemization of the remaining (R)-thioester. A hollow-fiber membrane was also integrated with the dynamic kinetic resolution process in order to continuously extract the desired (S)-suprofen into an aqueous solution containing NaOH. A kinetic model for the whole process (operating in batch and feed-batch modes) was developed, in which enzymatic hydrolysis and deactivation, lipase activation, racemization and non-enantioselective hydrolysis of the substrate by trioctylamine, and reactive extraction of (R)- and (S)-suprofen into the aqueous phase in the membrane were considered. Theoretical predictions from the model for the time-course variations of substrate and product concentrations in each phase were compared with experimental data.

Integration of reactive membrane extraction with lipase-hydrolysis dynamic kinetic resolution of naproxen 2,2,2-trifluoroethyl thioester in isooctane

Lipases immobilized on polypropylene powders have been used as the biocatalyst in the enantioselective hydrolysis of (S)-naproxen from racemic naproxen thioesters in isooctane, in which trioctylamine was added to perform in situ racemization of the remaining (R)-thioester substrate. A detailed study of the kinetics for hydrolysis and racemization indicates that increasing the trioctylamine concentration can activate and stabilize the lipase as well as enhance the racemization and non-stereoselective hydrolysis of the thioester. Effects of the aqueous pH value and trioctylamine concentration on (S)-naproxen dissociation and partitioning in the aqueous phase as well as the transportation in a hollow fiber membrane were further investigated. Good agreements between the experimental data and theoretical results were obtained when the dynamic kinetic resolution process was integrated with a hollow fiber membrane to reactively extract the desired (S)-naproxen out of the reaction medium.

Dynamic kinetic resolution of suprofen thioester via coupled trioctylamine and lipase catalysis

A lipase-catalyzed enantioselective hydrolysis process under conditions of continuous in situ racemization of substrate with trioctylamine as the catalyst was developed for the production of (S)-suprofen from (R,S)-suprofen 2,2,2-trifluoroethyl thioester in isooctane. A detailed investigation of trioctylamine concentration on the enzyme activation and stability as well as the kinetic behaviors of the thioester in racemization and enzymatic reaction was conducted, in which good agreement between the experimental data and theoretical results was observed. A complete conversion of the racemate for the desired (S)-suprofen in 95% ee(P) was obtained. Moreover, the recovery of the acid product by extraction and reuse of the organic solution were reported.

Lipase-catalyzed dynamic resolution of naproxen 2,2,2-trifluoroethyl thioester by hydrolysis in isooctane

A lipase-catalyzed enantioselective hydrolysis process under continuous in situ racemization of substrate by using trioctylamine as an organic base was developed for the production of (S)-naproxen from racemic naproxen thioesters in isooctane. Naproxen 2,2, 2-trifluoroethyl thioester and 45 degrees C were selected as the best substrate and temperature, respectively, by comparing the time-course variations for the racemization of (S)-naproxen thioesters containing an electron-withdrawing group. A detailed investigation of the effect of trioctylamine concentration on the kinetic behaviors of the thioester in racemization and enzymatic reaction was conducted, in which more than 70% conversion of the racemate (or 67.2% yield of (S)-naproxen) with eep value higher than 92% was obtained. Copyright 1999 John Wiley & Sons, Inc.

'Interfacial affinity chromatography' of lipases: separation of different fractions by selective adsorption on supports activated with hydrophobic groups

Lipases contained in commercial samples of lipase extracts from Rhizopus niveus (RNL) and Candida rugosa (CRL) have been selectively adsorbed on hydrophobic supports at very low ionic strength. Under these conditions, adsorption of other proteins (including some esterases) is almost negligible. More interestingly, these lipases could be separated in several active fractions as a function of a different rate or a different intensity of adsorption on supports activated with different hydrophobic groups (butyl-, phenyl- and octyl-agarose). Thus, although RNL seemed to be a homogeneous sample by SDS-PAGE, it could be separated, via sequential adsorption on the different supports, into three different fractions with very different thermal stability and substrate specificity. For example, one fraction hydrolyzed more rapidly ethyl acetate than ethyl butyrate, while another hydrolyzed the acetate ester 7-fold slower than the butyrate. Similar results were obtained with samples of CRL. Again, we could obtain three different fractions showing very different properties. For example, enantioselectivity for the hydrolysis of (R,S) 2-hydroxy-4-phenylbutanoic acid ethyl ester ranged from 1.2 to 12 for different CRL fractions. It seems that very slight structural differences may promote a quite different interfacial adsorption of lipases on hydrophobic supports as well as a quite different catalytic behavior. In this way, this new 'interfacial affinity chromatography' seems to be very suitable for an easy separation of such slightly different lipase forms.

Surfactant effect on enhancing (S)-naproxen prodrug production from racemic naproxen by lipase

In the enantioselective esterification of racemic naproxen with 4-(2-hydroxyethyl) morpholine by Lipase MY in organic solvents, a productivity improvement of the desired (S)-naproxen ester from 0.42 to 0.72 mM at the reaction time of 130 h was observed, when the surfactant bis (2-ethylhexyl) sodium sulfosuccinate (AOT) was added in the reaction mixture. The presence of a small amount of exogenously added water dramatically activated the enzyme in AOT/cyclohexane-reversed micelles. Desorption of the surfactant molecule from the enzyme mass and solubilization of the enzyme into reversed micelles were used to elucidate an existing maximum of the initial rate of (S)-naproxen synthesis with the water content. Moreover, the effects of alcohol and surfactant concentration on the enzyme activity are reported.