Tropical Journal of Pharmaceutical Research
Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
Vol. 1, No. 1, 2003, pp. 15-22
Bioline Code: pr02003
Full paper language: English
Document type: Research Article
Document available free of charge
Tropical Journal of Pharmaceutical Research, Vol. 1, No. 1, 2003, pp. 15-22
© Copyright 2002- Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, Nigeria.
Novel colorimetric assay of mefenamic acid using 4-amino-3,5-dinitrobenzoic acid (ADBA)|
SO Idowu, SC Tambo, AO Adegoke and AA Olaniyi
To develop a novel colorimetric assay method for mefenamic acid capsules.
The new method (aromatic ring derivatization technique) is based on a diazo coupling reactionusing diazotized 4-amino-3,5-dinitrobenzoic acid (ADBA) as a chromogenic derivatizing reagent.
Optimization studies showed that the coupling reaction is very fast and completed in less than 1 minute. A 1:1 drug to reagent stoichiometric ratio was obtained for the azo dye formed. The azo adduct formed exhibits bathochromic shift with absorption maximum (λmax) at 490 nm, which was selected as the analytical wavelength. Lower limit of quantitation of mefenamic acid was 1 μ g/ml. The assays were linear over the concentration range of 1 - 6 μ g/ml and reproducible. This new method has been successfully applied in the assay of mefenamic acid capsules with accuracy similar to the official (B.P) titrimetric method of assay (p>0.05) and has the advantages of speed, high sensitivity, lower limit of detection and can be automated.
The method developed could find application in in-process quality control of mefenamic acid capsules.
Mefenamic acid assay, 4-amino-3,5-dinitrobenzoic acid, colorimetry, diazotization
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