Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Insecticide (veterinary).
DEFINITION
Deltamethrin Pour-on is a pour-on solution. It contains Deltamethrin in a suitable, oily vehicle.
The pour-on complies with the requirements stated under Veterinary Liquid Preparations for Cutaneous Application and with the following requirements.
Content of deltamethrin, C22H19Br2NO3
90.0 to 110.0% of the stated amount.
IDENTIFICATION
In the Assay, the chromatogram obtained with solution (1) shows a peak with the same retention time as the peak in the chromatogram obtained with solution (2).
ASSAY
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Mix a weighed quantity of the preparation being examined containing 30 mg of Deltamethrin with sufficient hexane to produce 100 mL. Dilute 1 volume to 4 volumes with hexane.
(2) 0.0075% w/v of deltamethrin BPCRS in hexane.
(3) 0.0075% w/v of deltamethrin impurity standard BPCRS in hexane.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (25 cm × 4.6 mm) packed with particles of silica the surface of which has been modified with chemically-bonded nitro-phenyl groups (5 µm) (Nucleosil-NO2 is suitable).
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 2 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 230 nm.
(f) Inject 20 µL of each solution.
MOBILE PHASE
hexane containing 0.25% v/v of propan-2-ol.
SYSTEM SUITABILITY
The test is not valid unless, in the chromatogram obtained with solution (3), a peak due to (R)-deltamethrin appears immediately before the principal peak, as indicated in the reference chromatogram supplied with deltamethrin impurity standard BPCRS.
DETERMINATION OF CONTENT
Determine the weight per mL of the preparation, Appendix V G, and calculate the content of C22H19Br2NO3, weight in volume, using the declared content of C22H19Br2NO3 in deltamethrin BPCRS.
