Spectrophotometric determination of carbamazepine ... - MA Zayed

Spectrophotometric determination of carbamazepine and mosapride citrate in pure and
pharmaceutical preparations.
Eman Y.Z. Frag, M.A. Zayed*, M.M. Omar, Sally E.A. Elashery, Gehad G. Mohamed
Chemistry Department, Faculty of Science, Cairo University, Gamaa Str., 12613, Giza, Egypt
* Author for whom all correspondence should be addressed. (e-mail: mazayed429@yahoo.com)
Abstract
Simple, rapid and sensitive spectrophotometric methods were developed for the determination
of carbamazepine and mosapride citrate drugs in pure and pharmaceutical dosage forms. These
methods are based on ion pair and charge transfer complexation reactions. The first method is
based on the reaction of the carbamazepine drug with Mo(V)-thiocyanate in hydrochloric acid
medium followed by extraction of the coloured ion-pair with 1,2-dichloroethane and measured at
470 nm. The second method is based on the formation of ion-pairs between mosapride citrate and
two dyestuff reagents namely bromothymol blue (BTB) and bromocresol green (BCG) in universal
buffer of pH 4 and 3, respectively. The formed ion-pairs are extracted with chloroform and
methylene chloride and measured at 412 and 416 nm for BTB and BCG reagents, respectively. The
third method is based on charge transfer complex formation between mosapride citrate (electron
donor) and DDQ (π-acceptor reagent) and measurements at 450 nm. All the optimum conditions
are established. The calibration graphs are rectilinear in the concentration ranges 10-350 for
carbamazepine using Mo(V)-thiocyanate and 4-100, 4-60 and 10-150 μg mL -1 for mosapride citrate
using BTB, BCG and DDQ reagents, respectively. The Sandell sensitivity (S), molar absorptivity,
correlation coefficient, regression equations and limits of detection (LOD) and quantification
(LOQ) are calculated. The law values of standard deviation (0.04-0.09 for carbamazepine using
Mo(V)-thiocyanate and 0.022-0.024, 0.013-0.018 and 0.013-0.020 for mosapride citrate using
BTB, BCG and DDQ, respectively) and relative standard deviation (0.630-2.170 for carbamazepine
using Mo(V)-thiocyanate and 0.123-1.43, 0.102-0.530 and 0.226-1.280 for mosapride citrate using
BTB, BCG and DDQ, respectively) reflect the accuracy and precision of the proposed methods.
The methods are applied for the assay of the investigated two drugs in pharmaceutical dosage
forms. The results are in good agreement with those obtained by the official method.
Keywords: Carbamazepine and mosapride citrate; Ion-pair formation; Charge transfer;
Spectrophotometry.
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