monograph of chormephinecol

(Ph Eur monograph 0071)





C11H12Cl2N2O5 323.1 56-75-7
Action and use
Antibacterial.
Preparations
Chloramphenicol Capsules
Chloramphenicol Ear Drops
Chloramphenicol Eye Drops
Chloramphenicol Eye Ointment
Ph Eur
DEFINITION
Chloramphenicol is 2,2-dichloro-N-[(1R,2R)-2-hydroxy-1-(hydroxymethyl)-2-(4-nitrophenyl)ethyl]acetamide, produced by the growth of certain strains of Streptomyces venezuelae in a suitable medium. It is normally prepared by synthesis. It contains not less than 98.0 per cent and not more than the equivalent of 102.0 per cent of C11H12Cl2N2O5, calculated with reference to the dried substance.
CHARACTERS
A white, greyish-white or yellowish-white, fine, crystalline powder or fine crystals, needles or elongated plates, slightly soluble in water, freely soluble in alcohol and in propylene glycol, slightly soluble in ether.
A solution in ethanol is dextrorotatory and a solution in ethyl acetate is laevorotatory.
IDENTIFICATION
First identification A, B.
Second identification A, C, D, E.
A. Melting point (2.2.14): 149°C to 153°C.
B. Examine by infrared absorption spectrophotometry (2.2.24), comparing with the spectrum obtained with chloramphenicol CRS.
C. Examine the chromatograms obtained in the test for related substances. The principal spot in the chromatogram obtained with 1 ml of the test solution is similar in position and size to the principal spot in the chromatogram obtained with reference solution (a).
D. Dissolve about 10 mg in 1 ml of alcohol (50 per cent V/V) R, add 3 ml of a 10 g/l solution of calcium chloride R and 50 mg of zinc powder R and heat on a water-bath for 10 min. Filter the hot solution and allow to cool. Add 0.1 ml of benzoyl chloride R and shake for 1 min. Add 0.5 ml of ferric chloride solution R1 and 2 ml of chloroform R and shake. The aqueous layer is coloured light violet-red to purple.
E. To 50 mg in a porcelain crucible add 0.5 g of anhydrous sodium carbonate R. Heat over an open flame for 10 min. Allow to cool. Take up the residue with 5 ml of dilute nitric acid R and filter. To 1 ml of the filtrate add 1 ml of water R. The solution gives reaction (a) of chlorides (2.3.1).
TESTS
Acidity or alkalinity
To 0.1 g add 20 ml of carbon dioxide-free water R, shake and add 0.1 ml of bromothymol blue solution R1 . Not more than 0.1 ml of 0.02 M hydrochloric acid or 0.02 M sodium hydroxide is required to change the colour of the indicator.
Specific optical rotation (2.2.7)
Dissolve 1.50 g in ethanol R and dilute to 25.0 ml with the same solvent. The specific optical rotation is +18.5° to +20.5°.
Related substances
Examine by thin-layer chromatography (2.2.27), using silica gel GF 254 R as the coating substance.
Test solution Dissolve 0.10 g of the substance to be examined in acetone R and dilute to 10 ml with the same solvent.
Reference solution (a) Dissolve 0.10 g of chloramphenicol CRS in acetone R and dilute to 10 ml with the same solvent.
Reference solution (b) Dilute 0.5 ml of reference solution (a) to 100 ml with acetone R.
Apply separately to the plate 1 ml and 20 ml of the test solution, 1 ml of reference solution (a) and 20 ml of reference solution (b). Develop over a path of 15 cm using a mixture of 1 volume of water R, 10 volumes of methanol R and 90 volumes of chloroform R. Allow the plate to dry in air and examine in ultraviolet light at 254 nm. Any spot in the chromatogram obtained with 20 ml of the test solution, apart from the principal spot, is not more intense than the spot in the chromatogram obtained with reference solution (b) (0.5 per cent).
Chlorides (2.4.4)
To 1.00 g add 20 ml of water R and 10 ml of nitric acid R and shake for 5 min. Filter through a filter paper previously washed by filtering 5 ml portions of water R until 5 ml of filtrate no longer becomes opalescent on addition of 0.1 ml of nitric acid R and 0.1 ml of silver nitrate solution R1 . 15 ml of the filtrate complies with the limit test for chlorides (100 ppm).
Loss on drying (2.2.32)
Not more than 0.5 per cent, determined on 1.000 g by drying in an oven at 100°C to 105°C.
Sulphated ash (2.4.14)
Not more than 0.1 per cent, determined on 2.0 g.
Sterility (2.6.1)
If intended for use in the manufacture of a parenteral or ophthalmic dosage form without a further appropriate sterilisation procedure, it complies with the test for sterility.
Pyrogens (2.6.8)
If intended for use in the manufacture of a parenteral dosage form without a further appropriate procedure for the removal of pyrogens, it complies with the test for pyrogens. Inject per kilogram of the rabbit's mass 2.5 ml of a solution containing per millilitre 2 mg of the substance to be examined.
ASSAY
Dissolve 0.100 g in water R and dilute to 500.0 ml with the same solvent. Dilute 10.0 ml of this solution to 100.0 ml with water R. Measure the absorbance (2.2.25) at the maximum at 278 nm.
Calculate the content of C11H12Cl2N2O5 taking the specific absorbance to be 297.
STORAGE
Store protected from light. If the substance is sterile, store in a sterile, airtight, tamper-proof container .
LABELLING
The label states:
—where applicable, that the substance is sterile,
—where applicable, that the substance is apyrogenic.
Ph Eur