Assay of Phenobarbitone: Medicinal Chemistry Practical
BP406P Medicinal Chemistry I Practical
AIM :
To perform the Assay of Phenobarbitone.
REFERENCE:
- A textbook of Medicinal Chemistry-I, Pragi Arora, Varun Arora, Davinder Kumar, Page no:282,283.
- Indian Pharmacopoeia Volume III 2018,Page No:2899,2900.
REQUIREMENTS:
Sodium hydroxide, aldehyde free ethanol, benzoic acid, thymolphthalein solution,
silver nitrate, pyridine and ether, conical flask, burette, beaker, pipette etc.
PRINCIPILE:
Phenobarbitone is assayed by non-aqueous titration. In this method, the drug is dissolved in the pyridine and titrated with sodium hydroxide solution using thymolphthalein as an indicator.
PROCEDURE:
- STANDARDISATION OF SODIUM HYDROXIDE SOLUTION
Actually weighed 0.6g of benzoic acid and dissolved it in a mixture of 30ml of ethanol and 6ml of water and titrated with ethanolic sodium hydroxide solution using 0.2ml of thymolphthalein as an indicator.
ASSAY OF PHENOBARBITONE
Weighed and powdered 20 tablets. Weighed a quantity of the powder containing about 0.1g (100 mg ) of phenobarbitone in 5ml of pyridine add 0.25 ml of thymolphthalein solution and 10 ml of silver nitrate pyridine reagent and titrated with 0.1M ethanolic sodium hydroxide until the purely blue colour is obtained. Repeated the operation without the substance under examination.
The difference between the titrations represents the amount of sodium hydroxide required.
Equivalent factor: 1ml of 0.1M ethanolic sodium hydroxide=0.01161g of C12H12N2O3
REPORT
The percentage purity of Phenobarbitone was found to be =
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