Determination of zolpidem hemitartrate by quantitative HPTLC and LC

Two methods are described for the determination of zolpidem hemitartrate in presence of its degradation product. The first method was a TLC-UV densitometric one in which the mobile phase methanol: water (20:80) was used for developing the TLC plates. The R(f) of zolpidem hemitartrate was found to be 0.29+/-0.01 and that of its degradation product was 0.59+/-0.01. Linearity range was 0.5-4 microg/spot with mean recovery percentage (99.98+/-0.988)%. The second method was an HPLC method. HPLC was performed on a Bondapack C(18) column. The mobile phase was composed of a mixture of acetonitrile-0.01 M KH(2)PO(4) (40:60). The pH was adjusted to 3.5+/-0.1. Flow rate was 1.2 ml/min. Calibration graphs were linear in the range of 0.5-5 microg/ml with UV detection at 245 nm. Both methods have been successfully applied to pharmaceutical formulations. The results obtained were statistically compared with those obtained by applying the reported methods.