Liquid chromatographic determination of amoxycillin and clavulanic acid in pharmaceutical preparations

A liquid chromatographic method for the simultaneous determination of amoxycillin and potassium clavulanate in tablet and suspension preparations is presented. The method specifies reversed phase column and a buffered mobile phase (CH3OH + KH2PO4-buffer pH 6 + H2O, 15:1:84) isocratically at a rate of 1.0 ml min-1, with detection at 235 nm. The suitability of the chromatographic system developed is tested using replicate injections of the sample and standard preparations. The observed relative standard deviations (RSDs) were within 2%. Recovery experiments conducted utilizing the proposed method gives results of 101.5% +/- 1.72 (n = 6) and 101.22% +/- 1.93 (n = 6) for amoxycillin in tablets and powder for oral administration, respectively. Similarly, recovery experiments for clavulanic acid gave results of 100.33 +/- 1.90 (n = 6) and 99.61 +/- 1.32 (n = 6) in the tablets and suspension powder, respectively. Comparison of the proposed method with the USP method proved it to be satisfactory. The statistical F- and t-tests observed, indicated that there were no significant differences between the two methods regarding precision and accuracy.