Assay of Isonicotinic acid hydrazide: Lab Manual, PDF Journal, Download
BP607P Medicinal Chemistry III Practical: I Preparation of drugs Sulphanilamide * 7-Hydroxy, 4-methyl coumarin * Chlorobutanol * Triphenyl imidazole * Tolbutamide * Hexamine II Assay of drugs Isonicotinic acid hydrazide * Chloroquine * Metronidazole * Dapsone * Chlorpheniramine maleate * Benzyl penicillin III Microwave irradiation technique Synthesis of Phenytoin by Microwave * Synthesis of Aspirin by Microwave IV Drawing structures and reactions using chem draw®
Aim:
To determine the percentage purity of a given sample of Isonicotinic acid hydrazide tablet.
Principle:
Isonicotinic acid hydrazide/ isoniazid is an anti-tubercular drug. It is assayed by the direct titration of Potassium bromate with the addition of potassium bromide in the presence of an acid medium using hydrochloric acid.
During oxidation reaction liberated bromine reacts with isoniazid in an aqueous solution to form isonicotinic acid. Azo dye methyl red indicator is used in this titration, decolourized the red colour is the endpoint.
Reaction:

Procedure:
Preparation of 0.0167 M Potassium bromate solution:
About 5.566gm of Potassium bromate was dissolved in water and made up to 1000 ml with distilled water.
Standardisation of 0.0167 M Potassium bromate:
20 ml of the above solution was transferred in a glass stopper flask and 3 g of Potassium iodide and followed by 3 ml of HCl was added.
Allow to stand for 5 min, titrate liberated Iodine with 0.1 M sodium thiosulphate adding 3 ml of starch solution TS and the endpoint is approached.
Concentration of 0.0167 M Potassium bromate= Molarity of Sodium thiosulphate / Volume of Potassium bromate
Assay of Isonicotinic acid hydrazide tablet
- Twenty tablets were weighed accurately and pulverized.
- A weighed quantity of the tablet power equivalent to 0.25 mg INH was transferred into a clean and dry 100 ml volumetric flask, and then sufficient water was added to produce 100 ml. 20 ml of the above solution was taken.
- Then 100 ml of water, 20 ml of hydrochloric acid and 0.2 gm of Potassium bromide were added.
- Then titrated slowly with continuous shaking with 0.0167M potassium bromate using 0.05ml of methyl red as an indicator until the red colour disappears.
Each ml of 0.0167M Potassium bromate KBrO3 = 0.003439g of C6H7N3O.
Report:
The Molarity of 0.1 M Sodium nitrite
The percentage purity of the given isonicotinic acid Hydrazide tablet was found to be:
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Isoniazid is used with other medications to treat active tuberculosis (TB) infections. It is also used alone to prevent active TB infections in people who may be infected with the bacteria (people with positive TB skin test). Isoniazid is an antibiotic that works by stopping the growth of bacteria. This antibiotic treats only bacterial infections. It will not work for viral infections (such as common cold, or flu). Using any antibiotic when it is not needed can cause it to not work for future infections.