ACTA Pharmaceutica Sciencia 2006 , Vol 48 , Num 1
SPECTROPHOTOMETRIC METHODS FOR THE DETERMINATION OF LANSOPRAZOLE IN CAPSULES
ZEYNEP AYDOĞMUŞ
Istanbul University, Faculty of Pharmacy, Department of Analytical Chemistry, Beyazıt, Istanbul, Turkey Three simple, sensitive and accurate spectrophotometric methods for the determination of lansoprazole (L) in capsules have been developed. These methods are based on the ion-pair complexes of L formed with tropaeolin OO (TPOO) and eriochrome black T (EBT) in tartaric acid medium and with bromothymol blue (BTB) in nonbuffer aqueous medium. The coloured products are extracted with chloroform and quantitatively measured at 411 nm with TPOO, at 505 nm with EBT, and at 415 nm with BTB. Beer's law was obeyed over the concentration ranges of 2-18, 2-21 and 4-23 μg.mL-1 with molar absorptivites of 1.972 x 103, 1.591 x 103 and 1.485 x 103 L. mol-1.cm-1 for TPOO, BTB and EBT respectively. These methods have been successfully applied for the assay of drug in capsules. Statistical comparison of the results with the reference method showed good agreement and indicated no significant difference in accuracy and precision. Keywords : LANSOPRAZOLE, SPECTROPHOTOMETRY, ION-PAIR, TROPAEOLIN OO, ERIOCHROME BLACK T, BROMOTHYMOL BLUE

Istanbul Medipol University