Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Anthelminthic.
DEFINITION
Ivermectin Veterinary Oral Paste contains Ivermectin in a suitable basis.
The veterinary oral paste complies with the requirements stated under Veterinary Oral Pastes and with the following requirements.
Content of ivermectin, calculated as the sum of component H2B1a (C48H74O14) and component H2B1b (C47H72O14)
95.0 to 110.0% of the stated amount.
The ratio of the contents H2B1a / (H2B1a + H2B1b) is at least 90.0%.
IDENTIFICATION
A. Carry out the method for thin-layer chromatography, Appendix III A, using a silica gel 60 F254 precoated plate (Merck silica gel 60 F254 plates are suitable) and a mixture of 1 volume of concentrated ammonia R1, 9 volumes of methanol and 90 volumes of dichloromethane as the mobile phase. Apply separately to the plate 2 µL of each of the following solutions. For solution (1) add 10 mL of methanol to a quantity of the oral paste containing 5 mg of Ivermectin and mix with the aid of ultrasound until completely dispersed. Solution (2) contains 0.05% w/v of ivermectin BPCRS in methanol. After removal of the plate, allow it to dry in air and examine under ultraviolet light (254 nm and 366 nm). The principal spot in the chromatogram obtained with solution (1) is similar in position, colour and size to that in the chromatogram obtained with solution (2).
B. In the Assay, the chromatogram obtained with solution (1) shows two principal peaks with retention times similar to those of the two principal peaks in the chromatogram obtained with solution (2).
TESTS
Related substances
Carry out the method for liquid chromatography, Appendix III D, using the following solutions. For solution (1) disperse a quantity of the oral paste in methanol with the aid of ultrasound and add sufficient methanol to produce a solution containing 0.04% w/v of Ivermectin. Solutions (2), (3) and (4) contain 0.04% w/v, 0.0004% w/v and 0.00002% w/v respectively of ivermectin BPCRS in methanol. Inject 20 µL of each solution.
The chromatographic procedure may be carried out using (a) a stainless steel column (25 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 µm) (Apex ODS 1 is suitable), (b) as the mobile phase at a flow rate of 1.5 mL per minute a mixture of 39 volumes of water, 55 volumes of methanol and 106 volumes of acetonitrile and (c) a detection wavelength of 245 nm.
The test is not valid unless, in the chromatogram obtained with solution (2), the resolution factor between the first peak (component H2B1b) and the second peak (component H2B1a) is at least 3.0.
In the chromatogram obtained with solution (1) the area of any peak with a retention time of 1.3 to 1.5 relative to that of the principal peak is not greater than 3 times the area of the principal peak in the chromatogram obtained with solution (3) (3%), the area of any other secondary peak is not greater than the area of the principal peak in the chromatogram obtained with solution (3) (1%) and the sum of the areas of any such peaks is not greater than 6 times the area of the
principal peak in the chromatogram obtained with solution (3) (6%). Disregard any peak with an area less than the area of the principal peak in the chromatogram obtained with solution (4) (0.05%).
ASSAY
Carry out the method for liquid chromatography, Appendix III D, using the following solutions. For solution (1) disperse a quantity of the oral paste in methanol with the aid of ultrasound and add sufficient methanol to produce a solution containing 0.04% w/v of Ivermectin. Solution (2) contains 0.04% w/v of ivermectin BPCRS in methanol. Inject 20 µL of each solution.
The chromatographic conditions described under Related substances may be used.
Calculate the content of ivermectin (H2B1a + H2B1b) in the oral paste and the ratio H2B1a / (H2B1a + H2B1b) using as the declared content the contents of C48H74O14 (H2B1a) and C47H72O14 (H2B1b) in ivermectin BPCRS.
