Simple Spectrophotometric and HPTLC-Densitometric Methods for Determination of Cefdinir in Bulk Powder and Pharmaceuticals, and in Presence of its Hydrolytic Degradation Products.

The present work describes development and validation of four different stability indicating methods for quantitative analysis of cefdinir (CFD) in bulk powder and pharmaceuticals, and in the presence of its acid and alkaline induced hydrolytic degradation products. The first method is based on derivative spectrophotometry. First derivative spectrophotometry was applied where CFD was determined at 313.4 nm in the presence of its alkaline degradation product and also second derivative spectrophotometry where CFD was determined at 298.2 nm in the presence of its acid degradation product. The second method is based on the first derivative of ratio spectrophotometry of CFD at 312 nm in the presence of its acid degradation product and at 310.2 nm in the presence of its alkaline degradation product. The third method is based on the mean centering of ratio spectrophotometry where the drug was determined at 288.4 and 284.8nm in laboratory prepared mixtures with its acid and alkaline degradation products, respectively. The fourth method is HPTLC-densitometry using diethylether-methanol-water-glacial acetic acid (6: 3: 1: 0.05, v/v) as a developing system. Due to simplicity, rapidity and accuracy of the proposed stability indicating methods, they are effective for quality control analysis.

Interaction of Losartan potassium with the micelles of Triton X 100.

This study is an investigation of the physicochemical interaction of Losartan potassium (LST K), an angiotensin-II receptor (type AT1) antagonist, with micelles of triton X, a nonionic surfactant. The effect of micelles on the spectral properties of LSTK was monitored on at pH 7.4 and at room temperature. The spectrum of LST K showed gradual and progressive bathochromic and hypochromic shift in presence of increasing concentrations of triton X 100. The binding constant Kb of LST K to triton X 100 micelles was calculated using the differential absorbance at λ = 225 nm& was found to be 4.13 ± 0.35 ×105 mol-1 L. By using pseudo-phase model, the partition coefficient between the bulk water and Triton X 100 micelles, Kx, was calculated from both differential absorbance Δ A225, Kx = 2.26 ±0.12 x105 mol-1 L. The binding of LST K to Triton X 100 micelles implied a shift in drug acidity constant (Δ pKa = 0.8).