Cyclophosphamide Tablets

General Notices

Action and use

Cytotoxic alkylating agent.

Definition

Cyclophosphamide Tablets contain Cyclophosphamide. They are coated.

The tablets comply with the requirements stated under Tablets and with the following requirements.

Content of cyclophosphamide, C7H15Cl2N2O2P,H2O

92.5 to 107.5% of the stated amount.

Identification

A. Shake a quantity of the powdered tablets containing 0.2 g of Cyclophosphamide with 2 mL of chloroform and filter. The infrared absorption spectrum of the filtrate, Appendix II A, is concordant with the reference spectrum of cyclophosphamide (RS 079).
B. Extract a quantity of the powdered tablets containing 0.1 g of Cyclophosphamide with ether and evaporate the extract to dryness. Dissolve the residue in 10 mL of water and add 5 mL of silver nitrate solution; no precipitate is produced. Boil; a white precipitate is produced which is insoluble in nitric acid but dissolves in 5m ammonia from which it is reprecipitated on the addition of nitric acid.

Tests

Acidity

Shake a quantity of the powdered tablets containing 0.25 g of Cyclophosphamide with 20 mL of carbon dioxide-free water, filter and titrate the filtrate with 0.1m sodium hydroxide VS using phenolphthalein solution R1 as indicator. Not more than 0.2 mL of 0.1m sodium hydroxide VS is required to change the colour of the solution.

Related substances

Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.

(1) Shake vigorously a quantity of the powdered tablets containing 0.2 g of Cyclophosphamide with 50 mL of chloroform for 15 minutes, filter, evaporate the filtrate to dryness and dissolve the residue in 10 mL of ethanol (96%).
(2) Dilute 1 volume of solution (1) to 100 volumes with ethanol (96%).
chromatographic conditions
(a) Use as the coating silica gel G.
(b) Use the mobile phase as described below.
(c) Apply 10 µL of each solution.
(d) Develop the plate to 15 cm.
(e) After removal of the plate, dry it in a current of warm air and heat at 100° for 10 minutes. Place the plate while hot in a chromatography tank in which is placed an evaporating dish containing equal volumes of a 5% w/v solution of potassium permanganate and hydrochloric acid, close the tank and allow to stand for 2 minutes. Remove the plate and place it in a current of cold air until excess chlorine is removed and an area of coating below the line of application gives not more than a very faint blue colour with potassium iodide and starch solution; avoid prolonged exposure to cold air. Spray the plate with potassium iodide and starch solution and allow to stand for 5 minutes.
mobile phase

2 volumes of anhydrous formic acid, 4 volumes of acetone, 12 volumes of water and 80 volumes of butan-2-one.

limits

In the chromatogram obtained with solution (1):

any secondary spot is not more intense than the spot in the chromatogram obtained with solution (2) (1%).

Disregard any spot remaining on the line of application.

Assay

Weigh and powder 20 tablets. Dissolve a quantity of the powdered tablets containing 0.1 g of Cyclophosphamide in 30 mL of chloroform, shake vigorously for 15 minutes, filter (Whatman GF/F is suitable) and wash the filter with 15 mL of chloroform. Evaporate the combined filtrate and washings to dryness and dissolve the residue in 50 mL of a 0.1% w/v solution of sodium hydroxide in ethane-1,2-diol. Boil under a reflux condenser for 30 minutes and allow to cool. Rinse the condenser with 25 mL of water, add 75 mL of propan-2-ol, 15 mL of 2m nitric acid, 10 mL of 0.1m silver nitrate VS and 2 mL of ammonium iron(iii) sulfate solution R2 and titrate with 0.1m ammonium thiocyanate VS. Each mL of 0.1m silver nitrate VS is equivalent to 13.94 mg of C7H15Cl2N2O2P,H2O.