Menadiol Phosphate Tablets

General Notices

Action and use

Vitamin K analogue.

Definition

Menadiol Phosphate Tablets contain Menadiol Sodium Phosphate.

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

Content of menadiol phosphate, C11H12O8P2

92.5 to 107.5% of the stated amount.

Identification

A. Shake a quantity of the powdered tablets containing the equivalent of 0.15 g of menadiol phosphate with 15 mL of water, centrifuge and filter the supernatant liquid. To 10 mL of the filtrate add 10 mL of 1m sulfuric acid, 10 mL of 0.1m cerium(iv) sulfate and 1 mL of hydrogen peroxide solution (20 vol) and extract with two 10 mL quantities of chloroform. Evaporate the combined chloroform extracts to dryness in a water bath and dry the residue at 40° at a pressure not exceeding 0.7 kPa. The infrared absorption spectrum of the residue, Appendix II A, is concordant with the reference spectrum of menadione (RS 214).
B. To 50 mg of the residue obtained in test A add 5 mL of water followed by 75 mg of sodium metabisulfite, heat in a water bath, shaking vigorously, until an almost colourless solution is obtained and dilute to 50 mL with water. To 2 mL of the resulting solution add 2 mL of a mixture of equal volumes of 13.5m ammonia and ethanol (96%), shake and add 0.15 mL of ethyl cyanoacetate. A deep purplish-blue colour is produced which changes to green on the addition of 1 mL of 10m sodium hydroxide.

Tests

Related substances

Carry out in subdued light the method for thin-layer chromatography, Appendix III A, using silica gel GF254 as the coating substance and a mixture of 50 volumes of propan-1-ol, 50 volumes of a 2% w/v solution of ammonium chloride, 5 volumes of butan-1-ol and 1.5 volumes of diethylamine as the mobile phase. Apply separately to the plate 5 µL of each of the following solutions. For solution (1) shake a quantity of the powdered tablets containing the equivalent of 0.25 g of menadiol phosphate with 10 mL of methanol (50%) and filter. For solution (2) dilute 1 volume of solution (1) to 200 volumes with methanol (50%). Solution (3) contains 0.0080% w/v of 2-methyl-1,4-naphthoquinone in methanol. After removal of the plate, allow it to dry in air and examine under ultraviolet light (254 nm). Any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (3). Examine the plate under ultraviolet light (365 nm). Any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2).

Assay

Weigh and powder 20 tablets. Shake a quantity of the powder containing the equivalent of 10 mg of menadiol phosphate with 100 mL of 0.1m hydrochloric acid for 30 minutes. Dilute to 250 mL with 0.1m hydrochloric acid, filter and measure the absorbance of the filtrate at the maximum at 290 nm, Appendix II B. Calculate the content of C11H12O8P2 taking the value of A(1%, 1 cm), for a solution of C11H8Na4O8P2 in 0.1m hydrochloric acid, to be 138 at the maximum at 290 nm. Each mg of C11H8Na4O8P2 (menadiol sodium phosphate) is equivalent to 0.792 mg of C11H12O8P2 (menadiol phosphate).

Labelling

The quantity of active ingredient is stated in terms of the equivalent amount of menadiol phosphate.