Demeclocycline Capsules

General Notices

Action and use

Tetracycline antibacterial.

Definition

Demeclocycline Capsules contain Demeclocycline Hydrochloride.

The capsules comply with the requirements stated under Capsules and with the following requirements.

Content of demeclocycline hydrochloride, C21H21ClN2O8,HCl

90.0 to 107.0% 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 contents of the capsules containing 10 mg of Demeclocycline Hydrochloride with 20 mL of methanol and centrifuge.
(2) 0.05% w/v of demeclocycline hydrochloride BPCRS in methanol.
(3) 0.05% w/v of each of demeclocycline hydrochloride BPCRS, oxytetracycline hydrochloride BPCRS and metacycline hydrochloride BPCRS in methanol.
chromatographic conditions
(a) Use as the coating silica gel H. Adjust the pH of a 10% w/v solution of disodium edetate to 7.0 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 stream 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. Add 20 mL of warm methanol to a quantity of the contents of the capsules containing 10 mg of Demeclocycline Hydrochloride, allow to stand for 20 minutes, filter and evaporate the filtrate to dryness on a water bath. To 0.5 mg of the residue add 2 mL of sulfuric acid; a purple colour is produced. Add 1 mL of water; the colour changes to yellow.
C. To 1 mg of the residue obtained in test B add 7 mL of water and 7 mL of 2m hydrochloric acid and heat gently for 30 seconds. No colour is produced immediately.

Tests

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

Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

(1) After 45 minutes, withdraw a 10 ml sample of the medium and filter. Dilute the filtered solution, if necessary, with sufficient 0.1m hydrochloric acid to give a solution expected to contain about 0.015% w/v of Demeclocycline Hydrochloride.
(2) 0.015% w/v of demeclocycline hydrochloride BPCRS in 0.1m hydrochloric acid.
chromatographic conditions
(a) Use a stainless steel column (25 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 µm) (Lichrosorb RP18 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.

determination of content

Calculate the total content of demeclocycline hydrochloride, C21H21ClN2O8,HCl, in the medium using the declared content of C21H21ClN2O8,HCl in demeclocycline hydrochloride BPCRS.

Related substances

Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

(1) Mix a quantity of the contents of the capsules containing 0.5 g of Demeclocycline Hydrochloride with 50 mL of 0.01m hydrochloric acid, add sufficient 0.01m hydrochloric acid to produce 100 mL, filter and dilute 1 volume of the filtrate to 5 volumes with 0.01m hydrochloric acid.
(2) 0.010% w/v of demeclocycline hydrochloride BPCRS in 0.01m hydrochloric acid.
(3) 0.015% w/v of each of demeclocycline hydrochloride BPCRS and 4-epidemeclocycline hydrochloride EPCRS in 0.01m hydrochloric acid.
chromatographic conditions

The chromatographic conditions described under Dissolution may be used.

system suitability

The test is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the two principal peaks is at least 3.0.

limits

In the chromatogram obtained with solution (1):

the area of any secondary peak is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (10%);

the sum of the areas of all the secondary peaks is not greater than 1.5 times the area of the principal peak in the chromatogram obtained with solution (2) (15%).

Loss on drying

When dried at 60° at a pressure not exceeding 0.7 kPa for 3 hours, the contents of the capsules lose not more than 5.0% of their weight. Use 1 g.

Assay

Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

(1) Mix a quantity of the mixed contents of 20 capsules containing 0.5 g of Demeclocycline Hydrochloride with 50 mL of 0.01m hydrochloric acid, add sufficient 0.01m hydrochloric acid to produce 100 mL, filter and dilute 1 volume of the filtrate to 5 volumes with 0.01m hydrochloric acid.
(2) 0.10% w/v of demeclocycline hydrochloride BPCRS in 0.01m hydrochloric acid.
(3) 0.015% w/v of each of demeclocycline hydrochloride BPCRS and 4-epidemeclocycline hydrochloride EPCRS in 0.01m hydrochloric acid.
chromatographic conditions

The chromatographic conditions described under Dissolution may be used.

system suitability

The Assay is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the two principal peaks is at least 3.0.

determination of content

Calculate the content of C21H21ClN2O8,HCl in the capsules using the declared content of C21H21ClN2O8,HCl in demeclocycline hydrochloride BPCRS.