Objective:To establish a RP - HPLC for determination of amoxicillin and
dicloxacillin in amoxicillin/ dicloxacillin sodium
tablets. Method: Amoxicillin and
dicloxacillin in the tablets were determinated by HPLC with a Hypersil C18 column(250 mm×4. 6 mm, 10 μm)with UV detection at 230 nm,and the mobile phase was consisted of methyl alcohol and phosphoric buffer(52: 48,adjusted to pH 5. 0 +0. 1 with phosphoric acid) ,the flow rate was 1.0 mL·min-1 . Results: Amoxicillin and dicloxacillin in
amoxicillin/dicloxacillin sodium tablets can be separated. The calibration curve was linear(r =0. 999 9) within the range of 50 -500 μg·mL-1 for amoxicillin,the average recovery was 99. 92% with repeatability precision RSD was 0. 82% (n =6). The calibration curve was linear(r = 0. 999 9) within the range of 25 -250μg · mL-1 for dicloxacillin,the average recovery was 100. 2% with repeatability precision RSD was 0. 86% (n =6). Conclusion:This method is simple,quick ,accurate and the assay result is suitable for the quality control for amoxicillin and dicloxacillin in amoxicillin/dicloxacillin sodium tablets.