Aim:

To develop and to validate a simple, sensitive and fast method for the simultaneous determination of sulfamethoxazole (SMT), trimethoprim (TMP) and bromhexine (BMX) in veterinary formulation by high performance liquid chromatography according to the guidelines of the Validation and Control Guide for analytical quality of medicines in food products and veterinary medicines, RDC 166/2017 and international guides International Conference on Harmonization and International Association of Official Analytical Chemists.

Materials and methods:

The separation was performed on a ThermoScientific® C18 AcclaimTM120 analytical column (4.6 X 250 mm, 5 μm), with a flow rate of 0.7 mL min-1 and detection at 245 nm, 265 nm and 271 nm, for BMX, SMT and TMP, respectively. All measurements were performed in methanol: water (84:16 v/v; pH 3.0). The analytical curves were linear (r > 0.9997) in the concentration range of 15.0 to 30.0 μg-mL-1 for SMT, 3.0 to 9.0 μg-mL-1 for TMP and 0.5 to 2.0 μg-mL-1 for BMX.

Results:

The method proved to be accurate, with coefficients of variation below the maximum limit of 2.0%, robust, without significant influence of the variations used in the analysis, exact (recovery >99%) and selective, in the assessment of interference from adjuvants.

Conclusion:

Therefore, the developed method proved to be suitable for routine quality control analyzes for the simultaneous determination of SMT, TMP and BMX in pharmaceutical formulations.