Ibuprofen enzymatic

Fig. 7-19. Enzymatic resolution and separation of ibuprofen sulphonmethyl ester.

In this case study, an enzymatic hydrolysis reaction, the racemic ibuprofen ester, i.e. (R)-and (S)-ibuprofen esters in equimolar mixture, undergoes a kinetic resolution in a biphasic enzymatic membrane reactor (EMR). In kinetic resolution, the two enantiomers react at different rates lipase originated from Candida rugosa shows a greater stereopreference towards the (S)-enantiomer. The membrane module consisted of multiple bundles of polymeric hydrophilic hollow fibre. The membrane separated the two immiscible phases, i.e. organic in the shell side and aqueous in the lumen. Racemic substrate in the organic phase reacted with immobilised enzyme on the membrane where the hydrolysis reaction took place, and the product (S)-ibuprofen acid was extracted into the aqueous phase. 

The reaction under investigation is the enzymatic hydrolysis of racemic ethoxyethyl-ibuprofen ester. The (R)-ester is not active in the above reaction,1-3, thus simplifying the reaction mechanism, as shown in Figure 5.13. Because both enantiomers are converted according to fust-order kinetics, the conversion of one enantiomer is independent of the conversion of the other.4... 

The plotting of Dixon plot and its slope re-plot (see 5.9.5.9) is a commonly used graphical method for verification of kinetics mechanisms in a particular enzymatic reaction.9 The proposed kinetic mechanism for the system is valid if the experimental data fit the rate equation given by (5.9.4.4). In this attempt, different sets of experimental data for kinetic resolution of racemic ibuprofen ester by immobilised lipase in EMR were fitted into the rate equation of (5.7.5.6). The Dixon plot is presented in Figure 5.22. 

Scheme 7.12 Resolution of an ibuprofen ester derivative by enzymatic ammonolysis.

Long, W.S., Kamaruddin, A.H. and Bhatia, S. (2005) Enzyme kinetics of kinetic resolution of racemic ibuprofen ester using enzymatic membrane reactor. Chemical Engineering Science, 60 (18), 4957—1970. 

N. Mprk, H. Bundgaard, Stereoselective Enzymatic Hydrolysis of Various Ester Prodrugs of Ibuprofen and Flurbiprofen in Human Plasma , Pharm. Res. 1992, 9, 492 - 496. 

Dynamic kinetic resolution (DKR) is a process in which the resolution process is coupled with in situ racemization of unreacted substrate. This has been shown to be a potential and feasible method to produce 100 % theoretical yield. We have developed a chemo-enzymatic DKR to obtain higher desired yield for (5)-ibuprofen. The combined base catalyst with lipase has resulted in high conversion and excellent ee of the product. 

Procedure 3 Enzymatic Kinetic Resolution of (/ ,S)-2-Ethoxyethyl Ibuprofen Ester with Immobilized Lipase... 

The procedure shows that it is feasible to combine racemization with the kinetic resolution process (hence the DKR) of R,S)- ethoxyethyl ibuprofen ester. The chemical synthesis of the ester can be applied to any esters, as it is a common procedure. The immobilized lipase preparation procedure can also be used with any enzymes or support of choice. However, the enzyme loading will need to be optimized first. The procedures for the enzymatic kinetic resolution and DKR will need to be adjusted accordingly with different esters. Through this method, the enantiopurity of (5)-ibuprofen was found to be 99.4 % and the conversion was 85 %. It was demonstrated through our work that the synthesis of (5)-ibuprofen via DKR is highly dependent on the suitability of the reaction medium between enzymatic kinetic resolution and the racemization process. This is because the compatibility between both processes is crucial for the success of the DKR. The choice of base catalyst will vary from one reaction to another, but the basic procedures used in this work can be applied. DKRs of other profens have been reported by Lin and Tsai and Chen et al. ... 

Long, W.S. Kamaruddin, A.H. andBhatia, S., Chiral Resolution of Racemic Ibuprofen Ester in an Enzymatic Membrane Reactor. Journal of Membrane Science., 2005, 247, 185-200. 

The enzymatic enantioselective hydrolysis of esters of naproxen and ibuprofen has attracted considerable attention because the (S)-enantiomers of these nonsteroidal anti-inflammatory drugs (NSAIDs) are the pharmacologically active isomers. These reactions have been successfully performed in a range of ionic liquids (Figure 10.10) [60, 65, 121]. 

Figure 10.22 Supported ionic liquid membrane in the enzymatic resolution of ibuprofen.

Scheme 34 Flow scheme for the enzymatic resolution process of ibuprofen.

The first example of process intensification at DSM is the pilot-scale test of the enzymatic production of S-ibuprofen, a nonsteroidal, anti-inflammatory drug. The molecular scheme is given in Figure 5. More details can be found in Refs. 3 and 4. 

Figure 5 Production of S-ibuprofen with a racemization step and an enzymatic conversion using the carboxyl esterase enzyme.

Arylpropionic acids are important class of non-steroidal anti-inflammatory drugs (NSAID). Their pharmacological activity is mainly in one of both enantiomers. Thus, efforts had been made to access to the enantiomerically pure substance. The kinetic resolution of racemic 2-(2-fluoro-4-biphenyl) propanoic acid 56 and 2(4-isobutylphenyl) propanoic acid 59 (Ibuprofen) was performed via enzymatic esterification and transesterification using an alcohol and vinyl acetate, respectively in a membrane reactor. The unreacted acid is obtained in highly enantiomerically enriched form. A consecutive approach consisting of the enzymatic hydrolysis of the resulted esters is needed to achieve the alcohol in optically pure form.77... 

Recent studies in the pharmaceutical field using MBR technology are related to optical resolution of racemic mixtures or esters synthesis. The kinetic resolution of (R,S)-naproxen methyl esters to produce (S)-naproxen in emulsion enzyme membrane reactors (E-EMRs) where emulsion is produced by crossflow membrane emulsification [38, 39], and of racemic ibuprofen ester [40] were developed. The esters synthesis, like for example butyl laurate, by a covalent attachment of Candida antarctica lipase B (CALB) onto a ceramic support previously coated by polymers was recently described [41]. An enzymatic membrane reactor based on the immobilization of lipase on a ceramic support was used to perform interesterification between castor oil triglycerides and methyl oleate, reducing the viscosity of the substrate by injecting supercritical CO2 [42],... 

Anandamide is rapidly hydrolysed enzymatically to arachidonic acid and ethanol-amine by a fatty acid amide hydrolase (FAAH) [50], The molecular characterization, cloning and expression of FAAH have been reported in a recent study [51]. FAAH can be blocked with either the general serine protease inhibitor phenyl methy(sulphonyl fluoride [38] or with the highly efficient methyl arachidonyl fluorophsphonate [52], The non-steroidal antiinflammatory ibuprofen in therapeutic doses, but not aspirin, sulindac or acetaminophen, also inhibits anandamide metabolism [53], This observation may have therapeutic implications. 

Membranes are being frequently employed in the manufacturing of pharmaceuticals in combination with a bioreactor for enzymatic reactions. In DSM such a combination has been studied for the production of S -ibuprofen, via the hydrolysis of the (R,S)-ibuprofen methylester coupled to a racemization of the unwanted enantiomer. The esterase used for the above conversion is strongly deactivated by the product. To solve this problem, an ultrafiltration membrane unit has been coupled to the reactor, to remove in situ the product formed. The application of the ultrafiltration has led to a twofold increase of the conversion/productivity, as shown in Fig. 11. 

Goto, M., Noda, S., Kamiya, N., and Nakashio, R, Enzymatic resolution of racemic ibuprofen by surfactant-coated lipases in organic media, Biotechnol. Lett., 18, 839-844, 1996. 

Ibuprofen Lipase ex Candida antarctica SP 435 Racemic ibuprofen will be transformed to ester (CH3, CH2-CH2C1) and then hydrolyzed enzymatically [72]... 

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