Isoniazid Tablets

General Notices

Action and use

Antituberculosis drug.

Definition

Isoniazid Tablets contain Isoniazid.

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

Content of isoniazid, C6H7N3O

95.0 to 105.0% of the stated amount.

Identification

Shake a quantity of the powdered tablets containing 0.1 g of Isoniazid with 10 mL of ethanol (96%) for 15 minutes, centrifuge and decant the supernatant liquid. Extract the residue with two further 10-mL quantities of ethanol (96%) and evaporate the combined extracts to dryness. The infrared absorption spectrum of the residue, Appendix II A, is concordant with the reference spectrum of isoniazid (RS 196).

TEST

Dissolution

Comply with the requirements for Monographs of the British Pharmacopoeia in the dissolution test for tablets and capsules, Appendix XII B1.

test conditions
(a) Use Apparatus 1, rotating the basket at 100 revolutions per minute.
(b) Use 900 mL of water, at a temperature of 37°, as the medium.
procedure

After 45 minutes withdraw a 10 mL sample of the medium and measure the absorbance of the filtered sample, suitably diluted if necessary, at the maximum at 263 nm, Appendix II B.

determination of content

Calculate the total content of isoniazid, C6H7N3O, in the medium taking 307 as the value of A(1%, 1 cm) at the maximum at 263 nm.

Assay

Weigh and powder 20 tablets. Dissolve a quantity of the powder containing 150 mg of Isoniazid as completely as possible in water, filter and wash the residue with sufficient water to produce 250 mL. To 50 mL of the resulting solution add 50 mL of water, 20 mL of hydrochloric acid and 0.2 g of potassium bromide and titrate with 0.0167m potassium bromate VS determining the end point electrometrically. Each mL of 0.0167m potassium bromate VS is equivalent to 3.429 mg of C6H7N3O.

Storage

Isoniazid Tablets should be protected from light.