ABSTRACT
Some racemic nonsteroidal anti-inflammatory drugs, namely naproxen, indoprofen, ketoprofen, flurbiprofen, carprofen, cicloprofen, flunoxaprofen and suprofen were separated into their enantiomers by nano-LC. Chiral recognition was achieved adding to the mobile phase heptakis (2,3,6-tri-O-methyl)-beta-cyclodextrin (TM-beta-CD). Capillary columns of 100 microm id, packed with different RP particles were used for experiments. Effect of experimental parameters such as mobile phase composition, stationary phase type and length of packed capillary column on retention factor and chiral resolution of analytes were studied. The stationary phase type played a very important role in the enantiorecognition process. Best results in terms of highest enantioresolution factor and largest number of separated enantiomers were obtained reducing the particles size to 3 microm with RP(18) stationary phase. Most favourable mobile phase for enantiodiscrimination was obtained using relatively low concentrations of ACN (30%, v/v), 30 mM of TM-beta-CD and pH value of 3.0. The retention time of all studied enantiomers decreased by increasing the CD derivative concentration. The retention factors of selected studied compounds, specifically flurbiprofen, naproxen and suprofen, were measured employing TM-beta-CD concentrations in the range 0-40 mM. Assuming a 1:1 enantiomer/CD ratio, the apparent association constants of the studied enantiomers were calculated.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/isolation & purification , Chromatography, Liquid/methods , Nanotechnology/methods , beta-Cyclodextrins/chemistry , Benzoxazoles/chemistry , Benzoxazoles/isolation & purification , Carbazoles/chemistry , Carbazoles/isolation & purification , Chromatography, Liquid/instrumentation , Flurbiprofen/chemistry , Flurbiprofen/isolation & purification , Hydrogen-Ion Concentration , Indoprofen/chemistry , Indoprofen/isolation & purification , Ketoprofen/chemistry , Ketoprofen/isolation & purification , Methylation , Molecular Structure , Nanotechnology/instrumentation , Naproxen/chemistry , Naproxen/isolation & purification , Propionates/chemistry , Propionates/isolation & purification , Stereoisomerism , Suprofen/chemistry , Suprofen/isolation & purification , Time FactorsABSTRACT
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.
Subject(s)
Amines/chemistry , Lipase/chemistry , Membranes, Artificial , Microfluidics/methods , Models, Chemical , Suprofen/analogs & derivatives , Suprofen/chemistry , Suprofen/isolation & purification , Ultrafiltration/methods , Catalysis , Chemical Fractionation/methods , Computer Simulation , Enzyme Activation , Enzymes, Immobilized/chemistry , Fungal Proteins , Isomerism , KineticsABSTRACT
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.
