Calcium Folinate Injection

Vitamin B component.

Calcium Folinate Injection is a sterile solution of Calcium Folinate. It is either supplied as a ready-to-use solution or it is prepared by dissolving Calcium Folinate for Injection in the requisite amount of Water for Injections immediately before use.

The injection complies with the requirements stated under Parenteral Preparations and, when supplied as a ready-to-use solution, with the following requirements.

90.0 to 110.0% of the stated amount.

A. To a volume containing the equivalent of 20 mg of folinic acid add 40 mL of acetone, mix, allow to stand and then centrifuge, discarding the solvent. Suspend the residue in 40 mL of acetone and centrifuge. Dry the residue in a stream of nitrogen and then at a pressure of 0.7 kPa for 2 hours. The infrared absorption spectrum of the residue, Appendix II A, is concordant with the reference spectrum of calcium folinate (RS 368).

B. Yields reaction B characteristic of calcium salts, Appendix VI.

pH, 6.5 to 8.5, Appendix V L.

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

(1) Dilute with water, if necessary, a volume of the injection to produce a solution containing the equivalent of 0.1% w/v of folinic acid.

(2) Dilute 1 volume of solution (1) to 100 volumes with water.

(3) 0.001% w/v of formylfolic acid EPCRS in the mobile phase.

(4) Dilute 1 volume of solution (2) to 10 volumes with water.

(5) Mix 10 volumes of solution (2) with 5 volumes of solution (3).

(a) Use a stainless steel column (25 cm × 4.6 mm) packed with end-capped octadecylsilyl silica gel for chromatography (5 µm) (Hypersil ODS is suitable).

(b) Use isocratic elution and the mobile phase described below.

(c) Use a flow rate of 1 mL per minute.

(d) Use a column temperature of 40°.

(e) Use a detection wavelength of 280 nm.

(f) Inject 20 µL of each solution.

(g) For solution (1) allow the chromatography to proceed for 2.5 times the retention time of folinate.

220 mL of methanol and 780 mL of a solution containing 2.0 mL of tetrabutylammonium hydroxide solution and 2.2 g of disodium hydrogen orthophosphate, previously adjusted to pH 7.5 with 10% v/v orthophosphoric acid.

The test is not valid unless, in the chromatogram obtained with solution (5), the resolution factor between the peaks corresponding to calcium folinate and formylfolic acid is at least 2.2. If necessary, adjust the methanol content in the mobile phase.

In the chromatogram obtained with solution (1):

the area of any peak corresponding to formylfolic acid is not greater than the area of the principal peak in the chromatogram obtained with solution (3) (1%);

the area of any other secondary peak is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (1%);

the sum of the areas of any secondary peaks, excluding the peak corresponding to formylfolic acid, is not greater than 2.5 times the area of the principal peak in the chromatogram obtained with solution (2) (2.5%).

Disregard any peak with an area less than that of the principal peak in the chromatogram obtained with solution (4) (0.1%).

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

(1) Dilute a volume of the injection with water to produce a solution containing the equivalent of 0.01% w/v of folinic acid.

(2) 0.011% w/v of calcium folinate EPCRS in water.

(3) 5 volumes of a 0.001% w/v solution of formylfolic acid EPCRS in the mobile phase and 10 volumes of a 0.001% w/v solution of calcium folinate EPCRS in water.

The chromatographic conditions described under Related substances may be used.

The Assay is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the peaks corresponding to calcium folinate and formylfolic acid is at least 2.2. If necessary, adjust the methanol content in the mobile phase.

Calculate the content of C₂₀H₂₃N₇O₇ in the injection using the declared content of C₂₀H₂₁CaN₇O₇ in calcium folinate EPCRS. Each mg of C₂₀H₂₁CaN₇O₇ is equivalent to 0.9255 mg of C₂₀H₂₃N₇O₇.

When supplied as a ready-to-use solution, Calcium Folinate Injection should be protected from light and stored at a temperature of 2° to 8°.

The quantity of active ingredient is stated in terms of the equivalent amount of folinic acid.

Calcium Folinate for Injection is a sterile material consisting of Calcium Folinate with or without excipients. It is supplied in a sealed container.

The contents of the sealed container comply with the requirements for Powders for Injections or Infusions stated under Parenteral Preparations and with the following requirements.

90.0 to 110.0% of the stated amount.

A. The infrared absorption spectrum, Appendix II A, is concordant with the reference spectrum of calcium folinate (RS 368). If the spectra are not concordant prepare a solution containing 1% w/v of Calcium Folinate and carry out Identification Test A for the ready-to-use solution.

B. Yield reaction B characteristic of calcium salts, Appendix VI.

pH of a solution containing the equivalent of 1.0% w/v of folinic acid, 6.5 to 8.5, Appendix V L.

Carry out the test described for the ready-to-use solution but using the following solution as solution (1). Dissolve sufficient of the mixed contents of 10 containers in water to produce a solution containing the equivalent of 0.1% w/v of folinic acid.

Determine the weight of the contents of each of 10 containers as described in the test for Uniformity of weight under Parenteral Preparations of the British Pharmacopoeia, Powders for Injections.

Carry out the Assay described for the ready-to-use solution but using the following solution as solution (1). Dissolve sufficient of the mixed contents of the 10 containers in water to produce a solution containing the equivalent of 0.01% w/v of folinic acid.

Calculate the content of C₂₀H₂₃N₇O in a container of average content weight using the declared content of C₂₀H₂₁CaN₇O₇ in calcium folinate EPCRS. Each mg of C₂₀H₂₁CaN₇O₇ is equivalent to 0.9255 mg of C₂₀H₂₃N₇O₇.

The quantity of active ingredient is stated in terms of the equivalent amount of folinic acid.