EP 8.0 monograph: impurity determination of trimethoprim (for impurities H and I) using a cyano HPLC column

Instrument Type: HPLC

The Thermo Scientific Dionex UltiMate 3000 LC system is applied for the analysis of trimethoprim and its impurities (H and I). The separation was performed on a Thermo Scientific Betasil CN HPLC column using the method described in the EP 8.0 monograph. The results obtained for resolution and relative retention time (RRT) exceeded the criteria stated in the EP. Resolution between impurity B and trimethoprim was 5.9 (EP criteria of not less than 2.0), RRT of impurity H was 1.8 (EP criteria of about 1.8).