Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Tetracycline antibacterial.
DEFINITION
Chlortetracycline Tablets contain Chlortetracycline Hydrochloride.
The tablets comply with the requirements stated under Tablets and with the following requirements.
Content of chlortetracycline hydrochloride, C22H23ClN2O8,HCl
95.0 to 110.0% of the stated amount.
IDENTIFICATION
A. Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.
(1) Extract a quantity of the powdered tablets containing 10 mg of Chlortetracycline Hydrochloride with 20 mL of methanol and centrifuge.
(2) 0.05% w/v of chlortetracycline hydrochloride BPCRS in methanol.
(3) 0.05% w/v of each of chlortetracycline hydrochloride BPCRS, tetracycline hydrochloride BPCRS and metacycline hydrochloride BPCRS in methanol.
CHROMATOGRAPHIC CONDITIONS
(a) Use silica gel H as the coating. Adjust the pH of a 10% w/v solution of disodium edetate to 8.0 with 10M sodium hydroxide and spray the solution evenly onto the plate (about 10 mL for a plate 100 mm × 200 mm). Allow the plate to dry in a horizontal position for at least 1 hour. At the time of use, dry the plate in an oven at 110° for 1 hour.
(b) Use the mobile phase as described below.
(c) Apply 1 µL of each solution.
(d) Develop the plate to 15 cm.
(e) After removal of the plate, allow it to dry in a current of air and examine under ultraviolet light (365 nm).
MOBILE PHASE
6 volumes of water, 35 volumes of methanol and 59 volumes of dichloromethane.
SYSTEM SUITABILITY
The test is not valid unless the chromatogram obtained with solution (3) shows three clearly separated spots.
CONFIRMATION
The principal spot in the chromatogram obtained with solution (1) corresponds to that in the chromatogram obtained with solution (2).
B. To a quantity of the powdered tablets containing 10 mg of Chlortetracycline Hydrochloride add 20 mL of warm ethanol (96%), allow to stand for 20 minutes, filter and evaporate to dryness on a water bath. A 0.1% w/v solution of the residue in phosphate buffer pH 7.6, when heated at 100° for 1 minute, exhibits a strong blue fluorescence in ultraviolet light.
TESTS
Tetracycline hydrochloride and 4-epichlortetracycline hydrochloride
Not more than 8.0% and 6.0% respectively, determined as described under Assay. Inject separately solutions (1) and (4).
Dissolution
Comply with the requirements for Monographs of the British Pharmacopoeia in the dissolution test for tablets and capsules, Appendix XII B1.
TEST CONDITIONS
(a) Use Apparatus 2, rotating the paddle at 50 revolutions per minute.
(b) Use 900 mL of 0.1M hydrochloric acid, at a temperature of 37°, as the medium.
PROCEDURE
After 45 minutes withdraw a 10 mL sample of the medium and filter. Measure the absorbance of the filtered sample, suitably diluted with the dissolution medium if necessary, at the maximum at 266 nm, Appendix II B, using 0.1M hydrochloric acid in the reference cell.
DETERMINATION OF CONTENT
Calculate the total content of chlortetracycline hydrochloride, C22H23ClN2O8,HCl, in the medium taking 346 as the value of A(1%, 1 cm) at the maximum at 266 nm.
ASSAY
Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions prepared immediately before use.
(1) Mix a quantity of the powdered tablets containing 25 mg of Chlortetracycline Hydrochloride with 50 mL of 0.01M hydrochloric acid, shake for 10 minutes, dilute to 100 mL with 0.01M hydrochloric acid and filter (GF/C paper is suitable).
(2) 0.025% w/v of chlortetracycline hydrochloride BPCRS in 0.01M hydrochloric acid.
(3) 0.025% w/v of each of chlortetracycline hydrochloride BPCRS and 4-epichlortetracycline hydrochloride in 0.01M hydrochloric acid.
(4) 0.002% w/v of tetracycline hydrochloride BPCRS and 0.0015% w/v of 4-epichlortetracycline hydrochloride in 0.01M hydrochloric acid.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (25 cm × 4.6 mm) packed with end-capped octadecylsilyl silica gel for chromatography (10 µm) (Nucleosil C18 is suitable).
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 2 mL per minute.
(d) Use a column temperature of 40°.
(e) Use a detection wavelength of 355 nm.
(f) Inject 20 µL of each solution.
MOBILE PHASE
20 volumes of dimethylformamide and 80 volumes of 0.1M oxalic acid the pH of which has been adjusted to 2.2 with triethylamine.
SYSTEM SUITABILITY
The assay is not valid unless, in the chromatogram obtained with solution (3), the resolution between the two principal peaks is at least 1.5.
DETERMINATION OF CONTENT
Calculate the content of C22H23ClN2O8,HCl in the tablets using the declared content of C22H23ClN2O8,HCl in chlortetracycline hydrochloride BPCRS.
