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A stir membrane liquid phase microextraction procedure working under the three-phase mode is proposed for the first time for the determination of six anti-inflammatory drugs in human urine. The target compounds are isolated and preconcentrated using a special device that integrates the extractant and the stirring element. An alkaline aqueous solution is used as extractant phase while 1-octanol is selected as supported liquid membrane solvent. After the extraction, all the analytes are determined by liquid chromatography (LC) with ultraviolet detection (UV). The analytical method is optimized considering the main involved variables (e.g., pH of donor and acceptor phases, extraction time, stirring rate) and the results indicate that the determination of anti-inflammatory drugs at therapeutic and toxic levels is completely feasible. The limits of detection are in the range from 12.6 (indomethacin) to 30.7 μg/L (naproxen). The repeatability of the method, expressed as relative standard deviation (RSD, n = 5) varies between 3.4% (flurbiprofen) and 5.7% (ketoprofen), while the enrichment factors are in the range from 35.0 (naproxen) to 72.5 (indomethacin).

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.