Simultaneous estimation of amoxicillin and potassium clavulanate in injection formulation by dual wavelength spectroscopy

Abstract

A simple, fast and precise dual wavelength method has been developed for simultaneous determination of Amoxycillin (AMX) and Potassium clavulanate (PTC)for injection formulation. The absorption maxima were found 246.6 nm for AMX and 257.6 nm for PTC in 0.5M NaOH used as the solvent. It was found that the absorption maxima of these two drugs were quite close to each other; hence dual wavelength method was selected for their simultaneous estimation. For dual wavelength method two wavelengths selected were 261nm, 226nm and 279nm, 225 nm for AMX and PTC respectively because at these wavelengths drug shows similar absorbance. The developed method was then validated as per ICH guideline.RESULTS AND DISCUSSIONThe UV spectra of AMX and PTC, obtained from different solvent (methanol, water, 0.1mHCl and 0.1M NaOH ) were studied. The wavelength maximum of the main band was found to be dependent of solvent effects. In water ?max found to be 228nm AMX and 222nm for PTC, but theinjection powder was turbid and non filterable. Also the ?max of both drugs found to be very close. In 0.1M HCl drug is freely soluble and ?max found to be 229nm AMX and 224.2nm for PTC but the drug stock solution were dark and yellowish in cololur. In methanol drug is slightly soluble and ?max found to be 232nm AMX and 220.8nm for PTC, but as per solvent effect (Bathochromic shoft ) the ?max of PTC could not be considerable. In case of 0.1M NaOHthe drug is freely soluble and ?max found to be 246.8nm AMX and 257.6nm for PTC. Thus at the end of these studies 0.1M NaOH was selected as best solvent because it fulfill all the parameters required for simultaneous estimation and also to avoid the time gain while preparing solution and cost saving by eliminating the purchase and disposal of organic solvent. After considering the solubility, stability and economic feature for both the drugs, 0.1M NaOH was selected as