C6H8O7-H2O -- 210 -- 5949-29-1
Citric Acid BP Monohydrate
DEFINITION
2-Hydroxypropane-1,2,3-tricarboxylic acid monohydrate.
Content
99.5 per cent to 100.5 per cent (anhydrous substance).
CHARACTERS
Appearance
White or almost white, crystalline powder, colourless crystals or granules,
efflorescent.
Solubility
Very soluble in water, freely soluble in ethanol (96 per cent).
IDENTIFICATION
First identification B, E.
Second identification A, C, D, E.
A. Dissolve 1 g in 10 ml of water. The solution is strongly acidic.
B. Infrared absorption spectrophotometry.
C. Add about 5 mg to a mixture of 1 ml of acetic anhydride and 3 ml of pyridine. A red
colour develops.
D. Dissolve 0.5 g in 5 ml of water, neutralize using 1 M sodium hydroxide (about 7 ml),
add 10 ml of calcium chloride solution R and heat to boiling. A white precipitate is
formed.
E. Water (see Tests).
TESTS
Appearance of solution
The solution is clear and not more intensely coloured than reference.
Dissolve 2.0 g in water and dilute to 10 ml with the same solvent.
Readily carbonizable substances
To 1.0 g in a cleaned test tube add 10 ml of sulphuric acid and immediately heat the
mixture in a water-bath at 90 ± 1 °C for 60 min. Cool rapidly immediately afterwards.
The solution is not more intensely coloured than a mixture of 1 ml of red primary
solution and 9 ml of yellow primary solution.
Oxalic acid
Maximum 360 ppm, calculated as anhydrous oxalic acid.
Sulphates
Maximum 150 ppm.
Aluminium
Maximum 0.2 ppm, if intended for use in the manufacture of dialysis solutions.
Heavy metals
Maximum 10 ppm.
Water
7.5 per cent to 9.0 per cent, determined on 0.500 g.
Sulphated ash
Maximum 0.1 per cent, determined on 1.0 g.
Bacterial endotoxins
Less than 0.5 IU/mg, if intended for use in the manufacture of parenteral dosage forms
without a further appropriate procedure for the removal of bacterial endotoxins.
Citric Acid USP Monohydrate
C6H8O7·H2O 210.14
1,2,3-Propanetricarboxylic acid, 2-hydroxy-, monohydrate.
Citric Acid Monohydrate contains one molecule of water of hydration. It contains not
less than 99.5 percent and not more than 100.5 percent of C6H8O7, calculated on the
anhydrous basis.
Labeling— Where it is intended for use in dialysis solutions, it is so labeled.
Where Citric Acid Monohydrate must be subjected to further processing during the
preparation of injectable dosage forms to ensure acceptable levels of bacterial
endotoxins, it is so labeled. Where Citric Acid Monohydrate is sterile, it is so
labeled.
Identification, Infrared Absorption 197K— Dry the substance to be examined at 105
for 2 hours.
Bacterial endotoxins— The level of bacterial endotoxins is such that the
requirement in the relevant dosage form monograph (s) in which Citric Acid Monohydrate
is used can be met.
Sterility— Where the label states that Citric Acid Monohydrate is sterile, it
meets the requirements for Sterility, in the relevant dosage form monograph(s) in which
Citric Acid Monohydrate is used.
Water: between 7.5% and 9.0%.
Residue on ignition: Not more than 0.1%, determined on 1.0 g.
Readily carbonizable substances— To pass the test
Sulfate— 0.015%.
Heavy metals: 0.001%.
Limit of oxalic acid— 0.036%.
