Simultaneous determination of amoxycillin and clavulanic acid in pharmaceutical dosage forms by LC with amperometric...

A simple and sensitive liquid chromatographic method with electrochemical (EC) detection is described for the quantitative determination of amoxycillin and clavulanic acid in pharmaceutical dosage forms. Sample components were separated by a reversed phase C18 column, using a mixture of methanol-phosphate buffer (pH 3.2-3.4) (5:95, v/v) as the mobile phase. Detection of antibiotics was performed amperometrically by applying a potential of +1.25 V. High linearity over a concentration range of 15.625-500 ng was demonstrated for amoxycillin (r=0.9999) and clavulanic acid (r=0.9979). Detection limits were 0.8 ng ml(-1) for amoxycillin and 15 ng ml(-1) for clavulanic acid. This method was found to be convenient and reproducible for analysis of these two components in oral suspensions and tablets and might be useful for other pharmaceutical dosage forms.