Spectrophotometric determination of glucosamine sulphate after oxidation with sodium bismuthate

ABSTRACT

Tow simple and sensitive spectrophotometric methods are described for determination of glucosamine sulphate potassium chloride salt in pure form and in capsule dosage form. The tow methods are based on oxidation of glucosamine sulphate salt with sodium bismuthate in acetic acid medium. In method [A], the absorbance of the oxidation product is measured at 254 nm, and calibration curve in the range 5-25 microg/ml [-1][r = 0.9995] is constructed. In method [B] the oxidation product is reacted with oxalyldihydrazide in presence of copper [II] ions, and the absorbance of the condensation product is measured at 305 and 615 nm. Linear relationships are observed over the concentration ranges 20 - 100 and 10-100 microg/ml[-1] glucosamine sulphate salt with correlation coefficient 0.9998 and 0.9995 at the tow wave lengths, respectively. The conditions of the experimental parameters were carefully studied and optimized. The proposed methods were successfully applied for determination of glucosamine sulphate salt in pure form with average recoveries 100.46 +/- 2.43 [method A]. 100.03 +/- 1.46 [method B at 305 nm] and 99.92 +/- 1.62 [method B at 615 nm]. Glucosamine sulphate salt was determined in capsule dosage form by the proposed methods with average recoveries 97.10 +/- 0.73 [method A], 96.70 +/- 1.18 and 96.94 +/- 0.89 [method B] at 305 nm and 615 nm, respectively. The results obtained were in a good agreement with those of a well established comparison method: