Monographs: Pharmaceutical substances: Dapsonum - Dapsone

Molecular formula. C₁₂H₁₂N₂O₂S

Relative molecular mass. 248.3

Graphic formula.

Chemical name. 4,4'-Sulfonyldianiline; 4,4'-sulfonylbis[benzenamine]; 4,4'-diaminodiphenylsulfone; CAS Reg. No. 80-08-0.

Description. A white or creamy white, crystalline powder; odourless.

Solubility. Soluble in 7000 parts of water and in 30 parts of ethanol (~750 g/l) TS; soluble in acetone R.

Category. Antileprotic.

Storage. Dapsone should be kept in a tightly closed container, protected from light.

Additional information. Even in the absence of light, Dapsone is gradually degraded on exposure to a humid atmosphere, the decomposition being faster at higher temperatures.

Requirements

Definition. Dapsone contains not less than 99.0% and not more than 101.0% of C₁₂H₁₂N₂O₂S, calculated with reference to the dried substance.

Identity tests

A. The absorption spectrum of a 5.0 μg/ml solution in methanol R, when observed between 230 nm and 350 nm, exhibits maxima at about 260 nm and 295 nm; the absorbances of a 1-cm layer at the maximum wavelength of 260 nm and 295 nm are about 0.72 and 1.20, respectively.

B. See the test described below under "Related substances". The principal spot obtained with solution A corresponds in position, appearance, and intensity with that obtained with solution B.

C. About 0.1 g yields the reaction described for the identification of primary aromatic amines under 2.1 General identification tests, producing a vivid red precipitate.

D. Melting temperature, about 178°C.

Sulfated ash. Not more than 1.0 mg/g.

Loss on drying. Dry to constant weight at 105°C; it loses not more than 15 mg/g.

Related substances. Carry out the test as described under 1.14.1 Thin-layer chromatography, but using an unlined chamber, silica gel R3 as the coating substance, and a mixture of 8 volumes of toluene R and 4 volumes of acetone R saturated with water as the mobile phase. Apply separately to the plate 10 μl of each of 5 solutions in methanol R containing (A) 10 mg of the test substance per ml, (B) 10 mg of dapsone RS per ml, (C) 0.15 mg of the test substance per ml, (D) 20 μg of the test substance per ml and (E) 0.10 mg of 4,4'-thiodianiline RS per ml. The solution of 4,4'-thiodianiline RS should be freshly prepared. Pour the mobile phase into the chamber and insert the plate immediately, to avoid prior saturation of the chamber. After removing the plate from the chromatographic chamber, spray it with 4-dimethylaminocinnamaldehyde TS2. Heat the plate at 100°C and examine the chromatogram in daylight. The spot obtained with solution C is more intense than any spot obtained with solution A, other than the principal spot, and in addition, not more than 2 among those secondary spots are more intense than the spot obtained with solution D. Moreover, there is no visible spot corresponding in position and appearance with that obtained with solution E.

Assay. Carry out the assay as described under 2.7 Nitrite titration, using about 0.25 g, accurately weighed, dissolved in a mixture of 15 ml of water and 15 ml of hydrochloric acid (~70 g/l) TS and titrate with sodium nitrite (0.1 mol/l) VS. Each ml of sodium nitrite (0.1 mol/l) VS is equivalent to 12.42 mg of C₁₂H₁₂N₂O₂S.

Monographs: Pharmaceutical substances: Dactinomycinum - Dactinomycin

C₆₂H₈₆N₁₂O₁₆

Relative molecular mass. 1255

Chemical name. Actinomycin D; CAS Reg. No. 50-76-0.

Description. An orange-red to red, crystalline powder.

Solubility. Soluble in water at 10 °C and slightly soluble in water at 37 °C; freely soluble in ethanol (~750 g/l) TS and methanol R; very slightly soluble in ether R.

Category. Cytotoxic drug.

Storage. Dactinomycin should be kept in a tightly closed container, protected from light, and stored at a temperature not exceeding 40 °C.

Additional information. Dactinomycin is hygroscopic and is affected by light and heat.

CAUTION. Dactinomycin must be handled with care, avoiding contact with the skin and inhalation of airborne particles.

Requirements

Dactinomycin contains not less than 95.0% and not more than the equivalent of 103.0% of C₆₂H₈₆N₁₂O₁₆, calculated with reference to the dried substance.

Identity tests

A. The absorption spectrum of a 25 μg/ml solution in methanol R, when observed between 220 nm and 500 nm, exhibits 2 maxima at about 240 nm and 445 nm. The absorbance of a 1-cm layer at the maximum wavelength of 445 nm is about 0.83; the ratio of the absorbance at 240 nm to that at 445 nm is between 1.30 and 1.50.

B. Carry out the test as described under 1.14.1 Thin-layer chromatography, using silica gel R4 as the coating substance and a mixture of 4 volumes of 1-butanol R, 2 volumes of water, and 1 volume of methanol R as the mobile phase. Apply separately to the plate 10 μl of each of two solutions in acetone R containing (A) 10 mg of Dactinomycin per ml and (B) 10 mg of dactinomycin RS per ml. After removing the plate from the chromatographic chamber, allow it to dry in air, and examine the chromatogram in ultraviolet light (254 nm).

The principal spot obtained with solution A corresponds in position, appearance, and intensity with that obtained with solution B.

C. Add 1 mg to a solution of 10 mg of paraformaldehyde R in 1 ml of sulfuric acid (~1760 g/l) TS; a red-violet colour is produced.

Melting range. 235-237 °C.

Specific optical rotation. Use a 1.0 mg/ml solution in methanol R and calculate with reference to the dried substance;.

Sulfated ash. Not more than 5.0 mg/g.

Loss on drying. Dry at 60 °C under reduced pressure (not exceeding 0.6 kPa or 5 mm of mercury) for 3 hours; it loses not more than 50 mg/g.

pH value. pH of a saturated solution, 5.5-7.0.

Assay. Carry out the test as described under 1.14.4 High-performance liquid chromatography, using a column, length 30 cm, internal diameter 3.9 mm, packed with porous silica gel or ceramic microparticles having a diameter of 5-10 μm, the surface of which has been modified with chemically bonded octadecylsilyl groups.

As the mobile phase, use a mixture of 46 volumes of acetonitrile R, 25 volumes of sodium acetate (0.04 mol/l) VS and 25 volumes of acetic acid (0.07 mol/l) VS, filter through a membrane filter (porosity of 1 μm or finer) and degas the resulting solvent mixture. (Note: The concentration of acetonitrile may have to be adjusted to provide a suitable chromatogram and elution time.)

Prepare the following solutions immediately before use in the above-mentioned mobile phase, and store them protected from light. Weigh accurately for solution (A) about 1.2 mg of Dactinomycin per ml, and for solution (B) about 1.2 mg of dactinomycin RS per ml.

Operate with a flow rate of 1.0 ml per minute. As a detector use an ultraviolet spectrophotometer at a wavelength of about 254 nm. Make three replicate injections of solution B, each of 20 μl, to determine the peak responses. The relative standard deviation of the peaks is not more than 1.0%. Inject 20 μl of each of solutions A and B.

Measure the areas of the peak responses. (The retention time for dactinomycin is about 25 minutes.) Calculate the content in % of C₆₂H₈₆N₁₂O₁₆ using the following formula: (M₂/M₁) (A₁/A₂) 100, in which M₁ and M₂ are the concentrations , in mg per ml, of Dactinomycin being examined and the reference solution, and A₁ and A₂ are the areas of the peak responses of Dactinomycin and the reference substance, respectively.

Additional requirements for Dactinomycin for parenteral use

Complies with the monograph for "Parenteral preparations".

Bacterial endotoxins. Carry out the test as described under 3.4 Test for bacterial endotoxins; contains not more than 100.0 IU of endotoxin RS per mg.

Sterility. Complies with 3.2.2 Sterility testing of antibiotics, applying the membrane filtration test procedure and using a solution in sterile water R containing 20 mg of Dactinomycin per ml.

Monographs: Pharmaceutical substances: Dacarbazinum - Dacarbazine

Monographs: Pharmaceutical substances: Dacarbazinum - Dacarbazine

C₆H₁₀N₆O

Relative molecular mass. 182.2

Chemical name. 5-(3,3-Dimethyl-1-triazeno)imidazole-4-carboxamide; 5-(3,3-dimethyl-1-triazenyl)-1H-imidazole-4-carboxamide; CAS Reg. No. 4342-03-4.

Description. A colourless or pale yellow, crystalline powder.

Solubility. Slightly soluble in water and ethanol (~750 g/l) TS.

Category. Cytotoxic drug.

Storage. Dacarbazine should be kept in a tightly closed container, protected from light, and stored at a temperature not exceeding 8 °C.

Additional information. CAUTION: Dacarbazine must be handled with care, avoiding contact with the skin and inhalation of airborne particles.

Requirements

Dacarbazine contains not less than 97.0% and not more than 102.0% of C₆H₁₀N₆O, calculated with reference to the dried substance.

Identity tests

• Either test A alone or tests B, C, and D may be applied.

A. Carry out the examination as described under 1.7 Spectrophotometry in the infrared region. The infrared absorption spectrum is concordant with the spectrum obtained from dacarbazine RS or with the reference spectrum of dacarbazine.

B. The absorption spectrum of a 6μg/ml solution in hydrochloric acid (0.1mol/l) VS, when observed between 230nm and 350nm, exhibits a maximum at about 323nm and a pronounced shoulder at 275nm. The absorbance of a 1-cm layer at the maximum wavelength of 323 nm is about 0.64.

C. Dissolve 25 mg in 5 ml of water, add 1 drop of cobalt(II) chloride (30 g/l) TS and 1 drop of ammonia (~100 g/l) TS; a violet-red solution is produced.

D. Dissolve 25mg in 5ml of hydrochloric acid (~70 g/l) TS, add about 0.2 g of zinc R powder and allow to stand for 5 minutes. Filter, and to the filtrate add 3 drops of sodium nitrite (10 g/l) TS and 0.5ml of ammonium sulfamate (5 g/l) TS. After the reaction has subsided add 5 drops of N-(1-naphthyl)ethylenediamine hydrochloride/ethanol TS; a deep red solution is produced.

Clarity and colour of solution. A solution of 0.20 g in 10 ml of citric acid (20 g/l) TS is clear and not more intensely coloured than standard colour solution Yw2 when compared as described under 1.11 Colour of liquids.

Sulfated ash. Not more than 1.0 mg/g.

Loss on drying. Dry at 60 °C to constant mass under reduced pressure (not exceeding 0.6 kPa or about 5 mm of mercury); it loses not more than 5 mg/g.

Related substances. Carry out the test as described under 1.14.1 Thin-layer chromatography, using silica gel R2 as the coating substance and 5 volumes of 1-butanol R, 2 volumes of water and 1 volume of acetic acid (~300 g/l) TS as the mobile phase. Apply separately to the plate 5μl of each of the 3 following solutions in methanol R containing (A) 0.04 g of Dacarbazine per ml, (B) 0.4 mg of dacarbazine related compound A RS per ml, and (C) 0.4 mg of dacarbazine related compound B RS per ml. After removing the plate from the chromatographic chamber, allow it to dry in air, and examine the chromatogram in ultraviolet light (254 nm).

Any spot obtained with solution A, other than the principal spot, is not more intense or greater in size than that obtained with solution B (1%) and solution C (1%).

Assay

• The solutions must be protected from light throughout the assay.

Dissolve about 30 mg, accurately weighed, in sufficient hydrochloric acid (0.1 mol/l) VS to produce 50 ml of stock solution. For solution S₁ dilute 1.0ml of the stock solution to 100 ml with hydrochloric acid (0.1 mol/l) VS. For solution S₂ dilute a further 1.0 ml aliquot of the stock solution to 100ml with phosphate buffer, pH 7.0, TS. Measure the absorbance of a 1-cm layer of solution S₁ at the maximum at about 323nm against a solvent cell containing hydrochloric acid (0.1 mol/l) VS. Measure the absorbance of a 1-cm layer of solution S₂ at the maximum at about 329nm against a solvent cell containing phosphate buffer, pH 7.0, TS. Calculate the percentage content of C₆H₁₀N₆O.

Monographs: Pharmaceutical substances: Chloramphenicoli natrii succinas - Chloramphenicol sodium succinate

C₁₅H₁₅Cl₂N₂NaO₈

Relative molecular mass. 445.2

Chemical name. A mixture in variable proportions of (2R,3R)-2-(2,2- dichloroacetamido)-3-hydroxy-3-(4-nitrophenyl)propyl succinate (3 isomer) and of sodium (1R,2R)-2-(2,2-dichloroacetamido)-3-hydroxy-1-(4-nitrophenyl) propyl succinate (1 isomer); [R-(R*,R*)]-mono[2-[(2,2-dichloroacetyl)amino]-3-hydroxy-3-(4-nitrophenyl)propyl] ester, butanedioic acid, monosodium salt; D-threo-(-)-2,2-dichloro-N-[β-hydroxy-α-(hydroxymethyl)-p-nitrophenethyl] acetamide α-(sodium succinate); CAS Reg. No. 982-57-0.

Description. A white or yellowish white powder.

Solubility. Very soluble in water; freely soluble in ethanol (~750 g/l)TS.

Category. Antibacterial drug.

Storage. Chloramphenicol sodium succinate should be kept in a tightly closed container, protected from light.

Labelling. The designation Chloramphenicol sodium succinate for parenteral use indicates that the substance complies with the additional requirements and may be used for parenteral administration. Expiry date.

Additional information. Chloramphenicol sodium succinate is hygroscopic. Even in the absence of light, Chloramphenicol sodium succinate gradually degrades when exposed to a humid atmosphere; decomposition is more rapid at higher temperatures.

Requirements

Chloramphenicol sodium succinate contains not less than 98.0% and not more than the equivalent of 102.0% of C₁₅H₁₅Cl₂N₂NaO₈, calculated with reference to the anhydrous substance.

Identity tests

A. Carry out the examination as described under 1.7 Spectrophotometry in the infrared region. The infrared absorption spectrum is concordant with the spectrum obtained from chloramphenicol sodium succinate RS or with the reference spectrum of chloramphenicol sodium succinate.

B. See the test described below under "Chloramphenicol and chloramphenicol disodium disuccinate, test B". The two principal spots obtained with solution A correspond in position and appearance with those obtained with solution B. The positions of the spots obtained with solutions A and B are different from that of the principal spot obtained with solution C.

C. Dissolve 10 mg in 2.0 ml of ethanol (~750 g/l) TS, add 0.2 g of zinc R powder, 1.0 ml of sulfuric acid (~100 g/l) TS, and allow to stand for 10 minutes. Filter. To the filtrate add 0.5 ml of sodium nitrite (10 g/l) TS, and allow to stand for 2 minutes. Then add 1.0 g of urea R and a solution containing 10mg of 2-naphthol R in 2ml of sodium hydroxide (~80 g/l) TS; a red colour is produced. Repeat the test omitting the zinc R powder; no red colour is produced.

D. Dissolve 5 mg in 5 ml of water and add a few drops of silver nitrate (40 g/l) TS; no precipitate is produced. Heat 0.05g with 2.0ml of potassium hydroxide/ethanol TS1 on a water-bath for 15 minutes, add 15mg of charcoal R, shake, and filter. The filtrate yields reaction A described under 2.1 General identification tests as characteristic of chlorides.

E. When tested for sodium as described under 2.1 General identification tests, it yields the characteristic reactions. If reaction B is to be used, prepare a 20 mg/ml solution.

Specific optical rotation. Use a 50 mg/ml solution and calculate with reference to the anhydrous substance;

Clarity of solution. A solution of 1.0 g in 3.0 ml of carbon-dioxide-free water R is clear.

Water. Determine as described under 2.8 Determination of water by the Karl Fischer method, Method A, using about 0.5 g of Chloramphenicol sodium succinate; the water content is not more than 0.20 g/g.

pH value. pH of a 0.25 g/ml solution in carbon-dioxide-free water R, 6.4-7.0.

Chloramphenicol and chloramphenicol disodium disuccinate

• Either test A or test B may be applied.

A. Carry out the test as described under 1.14.4 High-performance liquid chromatography, using a stainless steel column (25cm × 4.6mm) packed with particles of silica gel, the surface of which has been modified with chemically bonded octadecylsilyl groups (5μm). As the mobile phase, use a mixture of 55 volumes of water, 40 volumes of methanol R, and 5 volumes of phosphoric acid (~20 g/l) TS.

Prepare the following solutions in the mobile phase: solution (A) 0.25mg of Chloramphenicol sodium succinate per ml; solution (B) 5.0 μg of chloramphenicol RS per ml; solution (C) 5.0 μg of chloramphenicol disodium disuccinate RS per ml; and for solution (D) dissolve 25mg of Chloramphenicol sodium succinate in the mobile phase, add 0.5 mg of chloramphenicol RS and 0.5 mg of chloramphenicol disodium disuccinate RS and dilute to 100ml with the mobile phase.

Operate with a flow rate of 1.0 ml per minute. As a detector use an ultraviolet spectrophotometer set at a wavelength of about 275nm.

Using a 20-μl loop injector inject solution D. Inject alternately solutions A, B, C, and D. The test is not valid unless the two peaks in the chromatogram obtained with solution D, corresponding to those in the chromatograms obtained with solutions B and C, are clearly separated from the peaks corresponding to the two principal peaks in the chromatogram obtained with solution A. If necessary, adjust the methanol content of the mobile phase.

Measure the areas of the peak responses obtained in the chromatograms from solutions A, B, and C, and calculate the content of the related substances as a percentage. In the chromatogram obtained with solution A, the area of any peak corresponding to chloramphenicol is not greater than that of the principal peak obtained with solution B (2.0%). The area of any peak corresponding to chloramphenicol disodium disuccinate is not greater than that of the principal peak obtained with solution C (2.0%).

B. Carry out the test as described under 1.14.1 Thin-layer chromatography, using silica gel R4 as the coating substance and a mixture of 85 volumes of dichloromethane R, 14 volumes of methanol R, and 1 volume of acetic acid (~60 g/l) TS as the mobile phase. Apply separately to the plate 2 μl of each of 3 solutions in acetone R containing (A) 10mg of Chloramphenicol sodium succinate per ml, (B) 10 mg of chloramphenicol sodium succinate RS per ml, and (C) 10 mg of chloramphenicol RS per ml. Then apply separately 10 μl of solution (A) as prepared above and 1 μl of solution (D) containing 0.20 mg of chloramphenicol RS per ml of acetone R. After removing the plate from the chromatographic chamber, allow it to dry in air until the solvents have evaporated, and examine the chromatogram in ultraviolet light (254 nm).

Any spot obtained with the second application of solution A, other than the principal spot, is not more intense than that obtained with solution D (2.0%).

Assay. Dissolve about 0.2 g, accurately weighed, in sufficient water to produce 500 ml; dilute 5.0 ml of this solution to 100 ml with water. Measure the absorbance of the diluted solution in a 1-cm layer at the maximum at about 276nm and calculate the percentage content of C₁₅H₁₅Cl₂N₂NaO₈ using the absorptivity value of 22.0 , and with reference to the anhydrous substance.

Additional requirements for Chloramphenicol sodium succinate for parenteral use

Complies with the monograph for "Parenteral preparations".

Storage. Sterile Chloramphenicol sodium succinate should be kept in a sterile, tightly closed, and tamper-evident container, protected from light.

Bacterial endotoxins. Carry out the test as described under 3.4 Test for bacterial endotoxins; contains not more than 0.2 IU of endotoxin RS per mg.

Sterility. Complies with 3.2.2 Sterility testing of antibiotics, Membrane filtration test procedure.

Monographs: Pharmaceutical substances: Chlorambucilum - Chlorambucil

Molecular formula. C₁₄H₁₉Cl₂NO₂

Relative molecular mass. 304.2

Graphic formula.

Chemical name. 4-[p-[Bis(2-chloroethyl)amino]phenyl]butyric acid; 4-[bis(2-chloroethyl)amino]benzenebutanoic acid; CAS Reg. No. 305-03-3.

Description. A white or almost white, crystalline or slightly granular powder.

Solubility. Practically insoluble in water; freely soluble in ethanol (~750 g/l) TS and acetone R.

Category. Cytotoxic drug.

Storage. Chlorambucil should be kept in a well-closed container, protected from light.

Additional information. CAUTION: Chlorambucil must be handled with care, avoiding contact with the skin and inhalation of airborne particles.

Requirements

Definition. Chlorambucil contains not less than 98.0% and not more than 101.0% of C₁₄H₁₉Cl₂NO₂, calculated with reference to the anhydrous substance.

Identity tests

A. Place 20 mg in a test-tube, add 0.20 ml of potassium dichromate TS2, cover the tube with a piece of filter-paper moistened with sodium nitroprusside (8.5 g/l) TS and 0.05 ml of piperidine R. Heat the tube over a small flame; a blue spot appears on the filter-paper.

B. Dissolve 0.05 g in 5 ml of acetone R, and dilute with water to 10 ml. Add 0.05 ml of sulfuric acid (~100 g/l) TS, then add 0.20 ml of silver nitrate (0.1 mol/l) VS; no opalescence is observed immediately (absence of chloride ion). Warm the solution on a water-bath; an opalescence develops (presence of ionizable chlorine).

C. Mix 0.4 g with 10 ml of hydrochloric acid (~70 g/l) TS and allow to stand for 30 minutes, shaking occasionally. Filter, wash the residue with 2 quantities, each of 10 ml of water, and dry at ambient temperature under reduced pressure (not exceeding 0.6 kPa or about 5 mm of mercury) over phosphorus pentoxide R for 3 hours; melting temperature, about 146°C.

Melting range. 64-69 °C.

Sulfated ash. Not more than 1.0 mg/g.

Water. Determine as described under 2.8 Determination of water by the Karl Fischer method, Method A, using about 0.5 g of the substance; the water content is not more than 5.0 mg/g.

Related substance. Carry out the test as described under 1.14.1 Thin-layer chromatography, using silica gel R2 as the coating substance and allowing the coated plate to dry at room temperature for 24 hours. Use as the mobile phase a mixture of 8 volumes of toluene R, 5 volumes of methanol R, 4 volumes of heptane R, and 4 volumes of ethylmethylketone R. Apply separately to the plate 10 μl of each of 2 solutions in acetone R containing (A) 20 mg of the test substance per ml and (B) 0.40 mg of the test substance per ml. After removing the plate from the chromatographic chamber, allow it to dry in air and examine the chromatogram in ultraviolet light (254 nm). Any spot obtained with solution A, other than the principal spot, is not more intense than that obtained with solution B.

Assay. Dissolve about 0.2 g, accurately weighed, in 10 ml of acetone R, add 10 ml of water, and titrate with carbonate-free sodium hydroxide (0.1 mol/l) VS using phenolphthalein/ethanol TS as indicator. Repeat the operation without the substance being examined and make any necessary corrections. Each ml of carbonate-free sodium hydroxide (0.1 mol/l) VS is equivalent to 30.42 mg of C₁₄H₁₉

Monographs: Pharmaceutical substances: Chlorali hydras - Chloral hydrate

C₂H₃Cl₃O₂

Relative molecular mass. 165.4

Chemical name. 2,2,2-Trichloroethane-1,1-diol; CAS Reg. No. 302-17-0.

Description. Colourless, transparent or white crystals; odour, aromatic, pungent and characteristic.

Solubility. Very soluble in water; freely soluble in ethanol (~750 g/l) TS and ether R.

Category. Premedication.

Storage. Chloral hydrate should be kept in a tightly closed container.

Additional information. Melting temperature, about 55 °C; when exposed to air it slowly volatilizes.

Requirements

Chloral hydrate contains not less than 98.5% and not more than 101.0% of C₂H₃Cl₃O₂.

Note: Prepare the following test solution for use in "Identity tests A and B", and for "Clarity and colour". Dissolve 2.5 g in sufficient carbon-dioxide-free water R to produce 25 ml.

Identity tests

A. To 1.0 ml of the test solution add 2.0 ml of sodium sulfide TS; a yellow colour develops which quickly becomes reddish brown. On standing, a red precipitate may be produced.

B. Transfer 10 ml of the test solution to a conical flask and add 10 ml of 1- ethylquinaldinium iodide (15 g/l) TS that has previously been filtered through a 0.45-μm filter. Then add 60ml of 2-propanol R, 5ml of monoethanolamine (0.1 mol/l) VS, and 15 ml of water. Mix, and heat in a water-bath at 60 °C for 15 minutes; a blue colour develops.

Chlorides. Dissolve 2.5 g in a mixture of 2 ml of nitric acid (~130 g/l) TS and 20 ml of water, and proceed as described under 2.2.1 Limit test for chlorides; the chloride content is not more than 0.1 mg/g.

Chloral alcoholate. Warm 1.0 g with 10 ml of sodium hydroxide (~80 g/l) TS. Filter the upper layer and add iodine (0.05 mol/l) VS a drop at a time until a yellow colour is obtained; no precipitate is produced within 1 hour.

Clarity and colour of solution. The test solution is clear and colourless.

Sulfated ash. Not more than 1.0 mg/g.

pH value. pH of a 0.10 g/ml solution in carbon-dioxide-free water R, 3.5-5.5.

Assay. Dissolve about 4 g, accurately weighed, in 10 ml of carbon-dioxide-free water R and add 30.0ml of carbonate-free sodium hydroxide (1 mol/l) VS. Allow the mixture to stand for 2 minutes and titrate with sulfuric acid (0.5 mol/l) VS, using phenolphthalein/ethanol TS as indicator. Repeat the procedure without the Chloral hydrate being examined and make any necessary corrections.

Each ml of carbonate-free sodium hydroxide (1 mol/l) VS is equivalent to 0.1654 g of C₂H₃Cl₃O₂.

Monographs: Pharmaceutical substances: Cetrimidum - Cetrimide

Chemical name. Trimethyltetradecylammonium bromide mixture with dodecyltrimethylammonium bromide and hexadecyltrimethylammonium bromide; cetrimide; CAS Reg. No. 8044-71-1.

Description. A white or almost white, voluminous, free-flowing powder; odour, slight, characteristic.

Solubility. Freely soluble in water and ethanol (~750 g/l) TS; practically insoluble in ether R.

Category. Antimicrobial preservative.

Storage. Cetrimide should be stored in a well-closed container.

Requirements

Definition. Cetrimide is a mixture consisting mainly of tetradecyltrimethylammonium bromide together with smaller amounts of dodecyltrimethylammonium bromide and hexadecyltrimethylammonium bromide.

Cetrimide contains not less than 96.0% and not more than the equivalent of 101.0% of alkyltrimethylammonium bromides, calculated as C₁₇H₃₈BrN (relative molecular mass = 336.4) and with reference to the dried substance.

Identity tests

A. Dissolve 5 mg in 5 ml of phosphate buffer, pH 8.0, TS. Dip a strip of methyl green/iodomercurate paper R into the solution. Similarly prepare a blank solution without the Cetrimide being examined. After 5 minutes withdraw the strip of paper from the tube; the solution to be tested shows a darker greenish blue colour than the blank solution.

B. Dissolve 0.2 g in 10 ml of carbon-dioxide-free water R and shake; a voluminous froth is produced. (Keep the mixture for test C.)

C. The solution prepared above yields reaction A described under 2.1 General identification tests as characteristic of bromides.

Amines and amine salts. Dissolve 5 g in 30 ml of a mixture of 1 volume of hydrochloric acid (1 mol/l) VS and 99 volumes of methanol R and add 100 ml of 2-propanol R. Slowly pass a stream of nitrogen R through the solution. Gradually add 15 ml of tetrabutylammonium hydroxide (0.1 mol/l) VS and titrate potentiometrically, recording a titration curve; the volume of titrant added between the two points of inflexion is not larger than 2.0 ml.

Sulfated ash. Not more than 5.0 mg/g.

Loss on drying. Dry at 105 °C for 2 hours; it loses not more than 20 mg/g.

Acidity or alkalinity. Dissolve 1 g in 50 ml of carbon-dioxide-free water R and add 0.1 ml of bromocresol purple/ethanol TS; not more than 0.1 ml of hydrochloric acid (0.1 mol/l) VS or 0.1 ml of sodium hydroxide (0.1 mol/l) VS is required to obtain the midpoint of the indicator (grey).

Assay. Dissolve about 2 g, accurately weighed, in 100 ml of water. Transfer 25 ml to a separating funnel, add 25 ml of chloroform R, 10 ml of sodium hydroxide (0.1 mol/l) VS, and 10 ml of a freshly prepared solution containing 5 g of potassium iodide R in 100 ml of water. Shake well, allow to separate, and discard the chloroform layer. Shake the aqueous layer with three quantities, each of 10 ml, of chloroform R, and discard the chloroform layers. Add 40 ml of hydrochloric acid (~420 g/l) TS, allow to cool, and titrate with potassium iodate (0.05 mol/l) VS until the deep brown colour is almost discharged. Add 2 ml of chloroform R and continue the titration, shaking vigorously, until the colour of the chloroform layer no longer changes. Repeat the procedure with a mixture of 10 ml of the above freshly prepared solution of potassium iodide, 20 ml of water, and 40 ml of hydrochloric acid (~420 g/l) TS and make any necessary corrections.

Each ml of potassium iodate (0.05 mol/l) VS is equivalent to 33.64 mg of C₁₇H₃₈BrN.