Compound Sodium Lactate Infusion

BP 2025 (Ph. Eur. 11.6 update)

DEFINITION

Compound Sodium Lactate Infusion is a sterile solution containing 0.32% w/v of sodium lactate with 0.6% w/v of Sodium Chloride, 0.04% w/v of Potassium Chloride and 0.027% w/v of Calcium Chloride Dihydrate in Water for Injections. It may be prepared from Sodium Lactate Solution or from Lactic Acid. It is supplied as a ready-to-use solution.

The infusion complies with the requirements stated under Parenteral Preparations and with the following requirements.

Content of sodium, Na

0.27 to 0.32% w/v.

Content of potassium, K

0.019 to 0.022% w/v.

Content of total chloride, Cl

0.37 to 0.42% w/v.

Content of calcium chloride dihydrate, CaCl₂,2H₂O

0.025 to 0.029% w/v.

Content of lactate, calculated as C₃H₆O₃

0.23 to 0.28% w/v.

CHARACTERISTICS

A colourless solution.

IDENTIFICATION

1. When warmed with potassium permanganate, acetaldehyde is evolved.
2. The residue obtained by evaporation, when moistened with hydrochloric acid and introduced on a platinum wire into a flame, imparts a yellow colour to the flame. When viewed through a suitable blue glass, the flame is tinged with reddish purple.
3. 5 mL of the infusion yields reaction C characteristic of calcium salts, Appendix VI.

TESTS

Acidity or alkalinity

pH, 5.0 to 7.0, Appendix V L.

Bacterial endotoxins

The endotoxin limit concentration is 0.25 IU per mL, Appendix XIV C.

ASSAY

For Na

Prepare a suitable dilution in water and determine by atomic emission spectrophotometry, Appendix II D, measuring at 589 nm and using sodium standard solution (200 ppm Na), suitably diluted with water, for the standard solutions.

For K

Prepare a suitable dilution in water and determine by atomic emission spectrophotometry, Appendix II D, measuring at 767 nm and using potassium standard solution (600 ppm K), suitably diluted with water, for the standard solutions.

For total chloride

To 20 mL add 30 mL of water, 50 mL of 0.1M silver nitrate VS and 2 mL of nitric acid, filter, wash the precipitate with water slightly acidified with nitric acid and titrate the excess of silver nitrate with 0.1M ammonium thiocyanate VS using ammonium iron(iii) sulfate solution R2 as indicator. Each mL of 0.1M silver nitrate VS is equivalent to 3.545 mg of total Cl.

For calcium chloride dihydrate

To 50 mL add 5 mL of 0.01m magnesium sulfate VS and 5 mL of ammonia buffer pH 10.9 and titrate with 0.01M disodium edetate VS using mordant black 11 triturate as indicator. From the volume of 0.01M disodium edetate VS required subtract the volume of 0.01M magnesium sulfate VS added. Each mL of the remainder is equivalent to 1.470 mg of CaCl₂,2H₂O.

For lactate, calculated as C₃H₆O₃

Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

1. Use the preparation being examined.
2. 0.28% w/v of lithium lactate BPCRS in the mobile phase.

CHROMATOGRAPHIC CONDITIONS

1. Use a stainless steel column (20 cm x 4.6 mm) packed with end-capped octadecylsilyl silica gel for chromatograpy (10 μm) (Nucleosil C18 is suitable).
2. Use isocratic elution and the mobile phase described below.
3. Use a flow rate of 2 mL per minute.
4. Use an ambient column temperature.
5. Use a detection wavelength of 210 nm.
6. Inject 20 μL of each solution.

MOBILE PHASE

10 volumes of a 2% v/v solution of octylamine in acetonitrile and 90 volumes of water, the pH of the final mixture being adjusted to 7.0 with a 10% v/v solution of orthophosphoric acid.

DETERMINATION OF CONTENT

Calculate the content of lactate, as C₃H₆O₃, in the infusion from the chromatograms obtained and using the declared equivalent content of C₃H₆O₃ in lithium lactate BPCRS.

LABELLING

The label states (1) that solutions containing visible solid particles must not be used; (2) that the Infusion contains, in millimoles per litre, the following approximate amounts of the ions present: sodium, 131; potassium, 5; calcium, 2; bicarbonate (as lactate), 29 and chloride, 111.