Development of Difference Spectroscopic Method for the Estimation of Lincomycin Hydrochloride in Bulk and Pharmaceutical Solid Dosage forms

A simple, precise and accurate difference spectroscopic method has been developed for the estimation of lincomycin hydrochloride (LMH) in bulk and pharmaceutical dosage form. The proposed method is based on the measurement of absorbance of Lincomycin hydrochloride at maxima 209 nm and minima 220 nm. The measurement value is the amplitude of maxima and minima between two equimolar solutions of the analyte in different chemical forms, which exhibits different spectral characteristics. Since the drug was freely soluble in distilled water, a stock solution (1mg/ml) was prepared with distilled water. Further dilution was made by using 0.1N sodium hydroxide and phosphate buffer of pH6.8 separately. The maxima and minima in the difference spectra of lincomycin hydrochloride were at 209 nm and 220 nm, respectively. Difference in absorbance between these maxima and minima was calculated to find out the amplitude. This amplitude was plotted against concentrations. The drug obeyed the beer's law in the concentration range 5-25μg/ml and showed good correlation. The result of analysis was validated by recovery studies.