Analytical Chemistry Department, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
Online published on 19 June, 2014.
Two spectrophotometric methods are described for determination of Lamotrigine, Minoxidil and Cefixime in bulk and pharmaceutical dosage forms using insitu generated bromine as oxidizing agent and either methyl orange or methylene blue as chromogenic agents. Drugs are treated with known excess of bromine and residual unreacted bromine is determined by treating with fixed amount of either methyl orange and measuring absorbance at 508 nm or methylene blue and measuring absorbance at 667 nm for minoxidil and lamotrigine and at 747 nm for cefixime. The amount of bromine reacted corresponds to the amount of each drug. Calibration curves were linear over ranges of 4.0 – 30.0, 0.5 – 4.0 and 0.5 – 5.0 μg.ml−1 for lamotrigine, minoxidil and cefixime, respectively in case of methyl orange and of 5.0 – 40.0, 0.5 – 7.0 and 2.0 – 5.5 μg.ml−1 for lamotrigine, minoxidil and cefixime, respectively in case of methylene blue. The methods were satisfactory applied for the determination of drugs in both bulk and pharmaceutical forms and results were compared statistically with reference methods.
