Abstract

QUANTITATIVE SPECTROPHOTOMETRIC DETERMINATION OF ARTESUNATE IN PHARMACEUTICALS USING THE IRONTHIOCYANATE COMPLEX FORMATION REACTION

Attih Emmanuel*, Usifoh C. O. Udobang John, Uwa Timma

ABSTRACT

A sensitive, accurate and reproducible spectrophotometric method is developed for the elimination of Artesunate in pharmaceutical formulations. This novel method is based on the oxidation of FeII to FeIII by artesunate in acid medium and the subsequent formation of Ferric-thiocynate complex (blood red) chromogen which absorbs, Uvvis light maximally at 480nm. Under optimized experimental conditions, the absorbance was found to increase linearly with the artesunate concentration. A calibration curve was generated which obeyed beer’s law within the range of 0.4 – 50 μg/ml with a linear coefficient of 9997, a slope of 0.0113 and a negligible intercept. The molar absorptivity and Sandell sensitivity were 1.08x104 LMol-1 CM-1 and 0.0356 μg/cm respectively. The limit of detection (LOD) and Limit of Qualification (LOQ) were 0.15 and 1.29 μg/ml respectively. The accuracy expressed as percentage relate error (ER%) and the corresponding precision expressed as relative standard deviation (RSD %) were <3.0% and <2.5% respectively. The proposed method was validated and used to assay artesunate in tablet formulations procured locally, the result obtained was statistically compared with official international pharmacopoeia method for artesunate; the result showing no difference in their means. The t and f value were <1.50 and > 2.76 respectively. The accuracy and practicability of the method was ascertained by recovery studies performed via standard addition method with the results showing high accuracy and virtually no interference from pharmaceutical excipients.

Keywords: Artesunate, Counterfeit, Malaria, Pharmaceutical, Spectrophotometry.