Analysis

A simple and sensitive spectrophotometric method has been developed for the determination of fexofenadine hydrochloride in bulk and pharmaceutical dosage forms. The method is based on the chloroform-extractable pale yellow colour complex formed by the reaction of fexofenadine with bromothymol blue at pH 2.6. The chromogen can be estimated at 412 nm against a reagent blank.

Difference spectrophotometric method was developed for the estimation of telmisartan in bulk drug and in pharmaceutical formulations. Telmisartan exists in two different forms in acidic and basic mediums that differ in their UV spectra.

Three simple, rapid and accurate visible spectrophotometric methods have been developed using Orange G dye for the quantitative estimation of citalopram hydrobromide, donepezil hydrochloride and rabeprazole sodium from respective tablet formulations. These developed methods are based on formation of chloroform-extractable coloured complex of drug and dye.

A reverse phase high performance liquid chromatography method was developed for simultaneous estimation of paracetamol and valdecoxib in tablet formulation. The separation was achieved by Luna C 18 column and methanol: phosphate buffer pH 3.5 (60:40 v/v) as eluent, at a flow rate of 1.0 ml/min. Detection was carried out at 242 nm. Etoricoxib was used as an internal standard.

Three new simple and sensitive spectrophotometric methods in ultraviolet region have been developed for the determination of gatifloxacin in bulk drug, pharmaceutical preparations and biological samples.

A simple, fast, precise and accurate RP-HPLC method was developed for the simultaneous estimation of valdecoxib and tizanidine hydrochloride in tablet formulations. The separation was achieved by C18 Intersil column and acetonitrile: 0.02 M phosphate buffer (pH 3.5) (60:40 v/v) as mobile phase, at a flow rate of 1.5 ml/min. Detection was carried out at 240 nm.

Two simple, sensitive, rapid, accurate and economical methods were developed for the estimation of ciprofloxacin and ornidazole in two-component solid dosage form. First method is based on the simultaneous equation, and second method is based on Q-analysis (absorbance ratio method). Ciprofloxacin has absorbance maxima at 271.4 nm, and ornidazole has absorbance maxima at 320 nm in distilled water.

A simple, fast, precise multicomponent mode analysis method has been developed for simultaneous estimation of ranitidine and domperidone in tablet formulation. The sampling wavelengths selected for both the drugs were 229 nm, 245 nm, 270 nm, 285 nm, 294 nm on trial-and-error basis using methanol as solvent.

Two simple, economical, precise and reproducible visible spectrophotometric methods have been developed for the estimation of repaglinide in tablet formulation. The developed methods are based on the formation of chloroform extractable complex of repaglinide with zincon and methylthymol blue in acidic medium.