Spectrophotometric Determination of Eszopiclone in Pure and Pharmaceutical Forms

Abstract

Six spectrophotometric methods for determination of eszopiclone have been developed, validated and applied for the assay of the drug in pharmaceuticals. Methods A, B, C and D are based on ion pair complexation of drug, in acidic buffers, with triphenylmethane dyes viz., Bromothymol blue(BTB), Bromophenol blue(BPB), Bromocresol green(BCG) and Bromocresol purple(BCP). The complexes are extracted into chloroform and absorbance is measured around at 415 nm as function of concentration of the drug. The stoichiometry of the complex is found 1:1 in each case. Method E depends upon charge transfer complexation of neutralized drug with iodine which produces iodide ion whose absorbance at 366 nm is measured as function of concentration of the drug. This complex, too, has 1:1 composition as determined by Job's method. Method F is developed on the basis of oxidation of the drug with alkaline KMnO 4 which generates green colored manganate ion with l max 610 nm. As the intensity of green color increased with increasing time kinetics of the reaction is followed and calibration curves are constructed by using initial rate and fixed time methods. Excellent recovery studies with high accuracy and precession indicate that the methods can be successfully used in industries for the assay of drug in pure form and pharmaceuticals.

Economic Electrochemical Sensors for the Determination of Eszopiclone in Pharmaceutical Formulation with Greenness Profile Assessment

“…Some analytical methods have been reported in literature for EZP determination, these include UV spectrophotometric [5–8], spectrofluorometric [9], HPLC [10–20], UPLC [13, 21, 22] and TLC [9, 23] methods. To the best of our knowledge no potentiometric techniques has been previously published for the determination of EZP.…”

“…United States Pharmacopoeia [4] recommends an HPLC assay of EZP achieved on octadecyl silane column (C18, 4.6-mm × 15.0-cm, 5-μm packing) with UV detection at 303 nm. Some analytical methods have been reported in literature for EZP determination, these include UV spectrophotometric [5][6][7][8], spectrofluorometric [9], HPLC [10][11][12][13][14][15][16][17][18][19][20], UPLC [13,21,22] and TLC [9,23] methods. To the best of our knowledge no potentiometric techniques has been previously published for the determination of EZP.…”