Isoniazid Tablets
Action and use
Antituberculosis drug.
Definition
Isoniazid Tablets contain Isoniazid.
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.
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.
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.