Sulbactam Sodium
C8H10NNaO5S Mol. Wt. 255.2
Sulbactam Sodium is (2S,5R)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate 4,4-dioxide.
Sulbactam Sodium contains not less than 97.0 per cent and not more than 102.0 per cent of C8H10NNaO5S, calculated on the anhydrous basis.
Category. Antibacterial.
Description. A white or almost white, hygroscopic, crystalline powder.
Identification
- Determine by infrared absorption spectrophotometry (2.4.6). Compare the spectrum with that obtained withsulbactam sodium RSor with the reference spectrum of sulbactam sodium.
- It gives reaction (A) of sodium (2.3.1).
Tests
Appearance of solution. Dissolve 2 g in water and dilute to 20 ml with the same solvent. Solution A is clear (2.4.1) and colourless (2.4.1).
Light absorption (2.4.7). Not more than 0.1. A 1 per cent w/v solution of the substance under examination in water. Measure the absorbance of the resulting solution at the maximum at about 430 nm (2.4.7).
pH (2.4.24). Dissolve 1 g in carbon dioxide-free water and dilute to 20 ml with the same solvent.
4.5 to 7.2, if the substance is sterile: 5.2 to 7.2.
Specific optical rotation (2.4.22). +219.0° to +233.0°, determined in a 1 per cent w/v solution in water.
Related substances. Determine by liquid chromatography (2.4.14).
Solvent mixture A. Dissolve 2.72 g of potassium dihydrogen orthophosphate in 1000 ml of water, adjusted to pH 4.0 with dilute orthophosphoric acid.
Solvent mixture B. Dilute 2.0 ml of acetonitrile to 100.0 ml with Solvent mixture A.
Test solution. Dissolve 77 mg of the substance under examination in 2 ml of acetonitrile, sonicate for 5 minutes and dilute to 100.0 ml with the Solvent mixture A.
Reference solution (a). Dissolve 70 mg of sulbactam RS in 2 ml of acetonitrile, sonicate for about 5 minutes and dilute to 100.0 ml with solution A.
Reference solution (b). Dilute 1.0 ml of reference solution (a) to 100.0 ml with solvent mixture B. Dilute 1.0 ml of this solution to 10.0 ml with solvent mixture B.
Reference solution (c). Dissolve 15 mg of 6-aminopenicillanic acid (impurity B) in solvent mixture A and dilute to 50.0 ml with solvent mixture A.
Reference solution (d). Mix 1.0 ml of reference solution (a) and 1.0 ml of reference solution (c) and dilute to 25.0 ml with solvent mixture B.
Reference solution (e). Dissolve 8 mg of sulbactam RS for peak identification (containing impurities A, C, D, E and F) in 1 ml of acetonitrile, sonicate for about 5 min and dilute to 10 ml with solvent mixture B.
Chromatographic system
– a stainless steel column 10 cm x 4.0 mm, packed with octadecylsilane bonded to porous silica (3 µm),
– column temperature: 40°C,
– mobile phase: A. dissolve 5.44 g of potassium dihydrogen orthophosphate in 1000 ml of water, adjusted to pH 4.0 with dilute orthophosphoric acid,
- A mixture of 40 volume of mobile phase Aand 60 volumes of acetonitrile,
– a gradient programme using the conditions given below,
– flow rate: 1 ml per minute,
– spectrophotometer set at 215 nm,
– injection volume: 20 µl.
Time Mobile phase A Mobile phase B
(in min.) (per cent w/v) (per cent w/v)
0 98 2
2.0 98 2
9.5 50 50
12.0 50 50
15.0 98 2
Name Retention time Correction
(in minutes) factor
Sulbactam 3.0 -
Sulbactam impurity A1 0.4 0.6
Sulbactam impurity B2 0.7 0.5
Sulbactam impurity C3 2.3 -
Sulbactam impurity D4 3.1 0.5
Sulbactam impurity E5 3.3 -
Sulbactam impurity F6 3.9 0.6
1(2S)-2-amino-3-methyl-3-sulfinobutanoic acid,
2(2S,5R,6R)-6-amino-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid (6-aminopenicillanic acid),
3(2S,5R,6R)-6-bromo-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid 4,4-dioxide (6-bromopenicillanic acid sulfone),
4(2S,5R,6R)-6-bromo-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid (6-bromopenicillanic acid),
5(2S,5R)-6,6-dibromo-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid 4,4-dioxide (6,6-dibromopenicillanic acid sulfone),
6(2S,5R)-6,6-dibromo-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid (6,6-dibromopenicillanic acid),
Inject reference solution (d).The test is not valid unless the resolution between the peaks due to sulbactam impurity B and sulbactam is not less than 5.0.
Inject reference solution (b), reference solution (e), solvent mixture B and the test solution. In the chromatogram obtained with the test solution, the area any peak due to sulbactam impurity A, is not more than 5.5 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.5 per cent). In the chromatogram obtained with the test solution, the area any peak due to sulbactam impurities C and E, is not more than 2.2 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.2 per cent). The area of any other secondary peak and due to sulbactam impurity B, D and F is not more than 1.1 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.1 per cent) and the sum of areas of all the secondary peaks is not more than 11 times the area of the principal peak in the chromatogram obtained with reference solution (b) (1.0 per cent). Ignore any peak with an area less than 0.55 times the area of the principal peak in the chromatogram obtained with reference solution (b) (0.05 per cent).
2-Ethylhexanoic acid (2.3.51). Not more than 0.5 per cent.
Water (2.3.43). Not more than 1.0 per cent, determined on 1 g.
Bacterial endotoxins (2.2.3). Not more than 0.17 Endotoxin Units per mg of sulbactam sodium.
Assay. Determine by liquid chromatography (2.4.14), as described under Related substances with the following modifications.
Inject reference solution (a) and test solution.
1 mg of sulbactam is equivalent to 1.094 mg of C8H10NNaO5S.
Calculate the content of C8H10NNaO5S.
Storage. Store protected from moisture. If the substance is sterile, store in a sterile, airtight, tamper-proof container