Spectrophotometric methods for determination of zolpidem tartrate in tablet formulation

The study aims to develop simple, sensitive, rapid, accurate and precise spectrophotometric method for estimation of Zolpidem tartrate in tablet dosage forms.

For method I, II, III and IV in a series of 10 ml volumetric flask, aliquots of standard drug solution (100 µg/ml) in 0.1N HCl were transferred and diluted with same so as to give several dilutions in concentration range of 5-30 µg/ml, 5-30 µg/ml, 10-50 µg/ml and 5-40 µg/ml respectively of zolpidem tartrate. To 5 ml of each dilution taken in a separating funnel, (5 ml of bromo phenol red, bromo cresol purple, bromo cresol green and bromo phenol blue for method I, II, III and IV respectively) reagent and 5 ml of chloroform was added. Reaction mixture was shaken gently for 5 min and allowed to stand so as to separate aqueous and chloroform layer. Absorbance maxima measured at 407 nm, 417 nm, 412 nm and 415 nm for method I, II, III and IV respectively.

The recovery studies were found close to 100 % that indicates accuracy and precision of the proposed methods. The statistical analysis was carried out and results of which were found satisfactory. Standard deviation values were found low that indicated reproducibility of the proposed methods.

Based on results the developed methods could be used for routine estimation of zolpidem tartrate from tablet formulations.