English abstract
Rapid, simple, specific, sensitive, economical and environmentally friendly method for the enantioseparation of racemic ketoprofen and ibuprofen and determination of pseudoephedrine are proposed using microfluidics precolumn derivatization. First, ketoprofen and ibuprofen enantiomers react with fluorogenic label (-)-nitro-7-(3-aminopyrrolidin-1-yl-2,1,benzoxadiazole (R-NBD-APY) within 5.0 minutes in microfluidics at room temperature in the presence of activation agents (2,2-dipyridyl disulfide and triphenyl phosphine) to produce diasetereomers. The microfluidics was connected to the HPLC system through a column switch where the diasetereomers were separated in RP-HPLC column and detected using fluorescence detection (Aex, 470 nm; Aem, 540 nm). The optimum conditions of the derivatizations separation have been established. The calibration curves were linear for the determination of the stereoisomers of ketoprofen and ibuprofen over the range from 0.001 to 0.028 mm. Second, pseudoephedrine enantiomers react with 4-chloro-7-nitrobenzofurazan (NBD-CI) within 2.5 minutes in the microfluidics at 70 °C, pH-10.5 to produce enantiomeric mixtures of PSEHNBD which could not be separated in RP-HPLC column with different type of B-cyclodextrin as chiral selector such as Methyl-B-cyclodextrin, and fluorescence detection (Aex, 475 nm; Aem, 532 nm). The separation of PSEH-NBD required further investigation. The calibration curve was linear for the determination of pseudoephedrine in the range of (0.006-0.200) mm. The application of the method to the pharmaceutical formulation analysis was demonstrated by enantioseparation of racemic ketoprofen, ibuprofen and determination of pseudoephedrine tablets that are available in the market in Sultanate of Oman.
