Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Antihelminthic.
DEFINITION
Ivermectin Oral Solution is a solution of Ivermectin in a suitable vehicle.
The oral solution complies with the requirements stated under Oral Liquids and with the following requirements.
Content of ivermectin, calculated as the sum of component H2B1a (C48H74O14) and component H2B1b (C47H72O14)
95.0 to 105.0% 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 the following solutions.
(1) Dilute a quantity of the oral solution with sufficient methanol to produce a solution containing 0.05% w/v of Ivermectin.
(2) 0.05% w/v of ivermectin BPCRS in methanol.
CHROMATOGRAPHIC CONDITIONS
(a) Use as the coating silica gel F254 (Merck silica gel 60 F254 plates are suitable).
(b) Use the mobile phase as described below.
(c) Apply 2 µL of each solution.
(d) Develop the plate to 15 cm.
(e) After removal of the plate, dry in air and examine under ultraviolet light (254 nm).
MOBILE PHASE
1 volume of concentrated ammonia R1, 9 volumes of methanol and 90 volumes of dichloromethane.
CONFIRMATION
The principal spot in the chromatogram obtained with solution (1) corresponds 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 peaks with the same retention times as the peaks due to Ivermectin H2B1a and Ivermectin H2B1b in the chromatogram obtained with solution (2).
TESTS
Related substances
Prepare a 0.0002% w/v solution of moxidectin BPCRS (internal standard) in acetonitrile (solution A).
Carry out the method for liquid chromatography, Appendix III D, using the following solutions prepared immediately before use.
(1) Dilute a weighed quantity of the oral solution containing 4 mg of Ivermectin with about 190 mL of acetonitrile, mix,
allow to cool to room temperature and add sufficient acetonitrile to produce 200 mL. Dilute 5 volumes of this solution to 50 volumes with solution A. Dry a portion of the resulting solution over anhydrous sodium sulfate and filter through a 0.45-µm filter.
(2) Dilute 2 volumes of a 0.02% w/v solution of ivermectin BPCRS in acetonitrile to 200 volumes with solution A.
(3) Dilute 2 volumes of solution (1) to 200 volumes with acetonitrile.
(4) Dilute 5 volumes of solution (3) to 50 volumes with acetonitrile. Derivatise the solutions prior to analysis using the following method.
Transfer 300 µL of the solution being examined to a 2-mL HPLC vial and add 130 µL of 1-methylimidazole and mix for 5 seconds using a vortex mixer, allow to settle and mix again for 5 seconds. Add 200 µL of a 50% v/v solution of trifluoroacetic anhydride in acetonitrile and mix for 5 seconds using a vortex mixer, allow to settle and mix again for 5 seconds.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (10 cm × 3.0 mm) packed with octadecylsilyl silica gel for chromatography (2.5 µm) (Phenomenex Luna C18 HST is suitable).
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 1.2 mL per minute.
(d) Use a column temperature of 40°.
(e) Use a fluorescence detector with an excitation wavelength of 365 nm and an emission wavelength of 470 nm.
(f) Inject 20 µL of each solution.
MOBILE PHASE
To 120 mL of water add 1.2 mL of orthophosphoric acid and 1.2 mL of triethylamine. Add 1880 mL of acetonitrile, mix and filter through a 0.45-µm filter.
When the chromatograms are recorded under the prescribed conditions the retention times relative to ivermectin H2B1a (retention time, about 7 minutes) are: avermectin B1, about 0.6; ivermectin H2B1b, about 0.8; ivermectin H4B1a, about 1.2).
SYSTEM SUITABILITY
The test is not valid unless:
in the chromatogram obtained with solution (2), the resolution factor between the peaks due to ivermectin H2B1a and ivermectin H2B1b is at least 3.0;
in the chromatogram obtained with solution (4), the signal-to-noise ratio of the principal peak is at least 10.
LIMITS
In the chromatogram obtained with solution (1):
the area of any secondary peak is not greater than 2.5 times the area of the principal peak in the chromatogram obtained with solution (3) (2.5%);
the area of not more than one secondary peak is greater than the area of the principal peak in the chromatogram obtained with solution (3) (1%);
the sum of the areas of all the secondary peaks is not greater than 5 times the area of the principal peak in the chromatogram obtained with solution (3) (5%).
Disregard any peak with an area less than the area of the principal peak in the chromatogram obtained with solution (4) (0.1%).
ASSAY
Carry out the method for liquid chromatography, Appendix III D, using derivatised solutions (1) and (2) described under Related substances.
CHROMATOGRAPHIC CONDITIONS
The chromatographic conditions described under Related substances may be used.
SYSTEM SUITABILITY
The test is not valid unless, in the chromatogram obtained with solution (2), the resolution factor between the peaks due to ivermectin H2B1a and ivermectin H2B1b is at least 3.0.
DETERMINATION OF CONTENT
Determine the weight per ml of the oral solution, Appendix V G, and calculate the content of ivermectin (H2B1a + H2B1b), weight in volume, and the ratio H2B1a / (H2B1a + H2B1b) using as the declared content the contents of C48H74O14 (H2B1a) and C47H72O14 (H2B1b) in ivermectin BPCRS.
