Calcium Folinate Tablets

General Notices

Action and use

Vitamin B component.

Definition

Calcium Folinate Tablets contain Calcium Folinate.

The tablets comply with the requirements stated under Tablets and with the following requirements.

Content of folinic acid, C₂₀H₂₃N₇O₇

90.0 to 110.0% of the stated amount.

Identification

A. To a quantity of the powdered tablets containing the equivalent of 180 mg of folinic acid add 10 mL of water, mix with the aid of ultrasound, and filter. Add 125 mg of ammonium oxalate to the filtrate, shake, and centrifuge until a clear supernatant liquid is obtained. To the supernatant add 1 mL of methanol and 3 drops of hydrochloric acid, and shake. If the preparation is cloudy, add methanol until a clear solution is obtained and filter, if necessary, to remove any undissolved material. Cool the preparation at 0° until a precipitate forms and centrifuge. The cooling and centrifuging steps may be repeated, if necessary, to increase the amount of precipitate collected. Decant the supernatant liquid and dissolve the precipitate in 2 mL of methanol. Evaporate to dryness under a current of air and dry the residue at 50° for 30 minutes. The infrared absorption spectrum of the residue, Appendix II A, is concordant with the reference spectrum of calcium folinate (RS 368).

B. The powdered tablets yield reaction B characteristic of calcium salts, Appendix VI.

Tests

Related substances

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

(1) Add 20 mL of water to a quantity of the powdered tablets containing the equivalent of 25 mg of folinic acid, shake for 15 minutes and dilute to 25 mL with water. Filter through a glass fibre filter (Whatman GF/C is suitable).

(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) 0.001% w/v of calcium folinate BPCRS in water.

(5) 0.0001% w/v of calcium folinate BPCRS in water.

(6) Mix 5 volumes of solution (3) with 10 volumes of solution (4).

chromatographic conditions

(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.

(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.

mobile phase

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.

system suitability

The test is not valid unless, in the chromatogram obtained with solution (6), 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.

limits

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 (5) (0.1%).

Assay

Protect the solutions from light. Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

(1) Add 200 mL of water to a quantity of the powdered tablets containing the equivalent of 25 mg of folinic acid, shake for 15 minutes and dilute to 250 mL with water. Filter through a glass fibre filter (Whatman GF/C is suitable).

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

chromatographic conditions

The chromatographic conditions described under Related substances may be used.

system suitability

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.

determination of content

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

Storage

Calcium Folinate Tablets should be stored at a temperature not exceeding 30°.

Labelling

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