A comparative study for the Determination of aspartame in pharmaceutical preparations by Kinetic Spectrophotometric and Reverse Phase-High Performance Liquid Chromatography methods.


This investigation involves development of a new kinetic spectrophotometric and a reverse phase-high performance liquid chromatography (RP-HPLC) methods for the determination of aspartame AS in pharmaceutical preparations. Spectrophotometric method was based on the oxidation of the drug AS with alkaline potassium permanganate. The reaction is followed spectrometrically by measuring the rate change of the absorbance of AS at 600nm. A fixed-time (at 48 min) method is adopted for determining the drug concentration. A linear calibration graph was in the range of 1-7μg.ml-1, with a correlation coefficient of 0.9998, detection limit of 0.101μg.ml-1, molar absorption coefficient is 5.2×104 L/mol.cm, Sandels sensitivity (S) 0.0056 μg/cm2 and relative standard deviation RSD% of 1.40%. In HPLC method, the drug was analyzed using RP-HPLC method with a Zorbax ODS-C18 (15cm×4.6mm i.d); analytical column (5μm partical size) and Isocratic elution with a mobile phase containing 15% acetonitrile in 0.02M sodium acetate buffer (pH 5.4), at a flow rate of 1ml.min-1, 20 μl sample loop, and the UV detector was set at λmax 220nm, Calibration graph was in the range of 10-70 μg.ml-1 with a correlation coefficient of 0.9991, detection limit of 1.09μg.ml-1 and a relative standard deviation of 0.91%.The two methods were applied successfully to determine the content of AS in pharmaceutical preparations with a recovery of 98.8-99.3%.