Assay of Chlorpheniramine maleate
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 given sample of Chlorpheniramine malate.
Principle:
Chlorpheniramine maleate chemically known as 3-(4-chlorophenyl) N, N- Dimethyl-3-(2-pyridyl) propylamine hydrogen maleate is an anti-histamine H1 receptor antagonist. Mineral acid salts of weak nitrogen bases hydrolyse so extensively in an aqueous or hydro-alcoholic solution that is possible to titrate the liberated acid with a strong mineral base.
Titration of the maleate salt of the drug in the water against the sodium hydroxide leads to the formation of water turbidity as the titration proceeds. To prevent this precipitation, alcohol has been used. Since alcohol is basic with respect to water as a solvent, dissolved bases react less strongly alkaline, their salts react more strongly acid, and the endpoints of the titrations are greatly sharpened, here an aqueous solution of Chlorpheniramine maleate was titrated with aqueous NaOH, the turbidity was formed with the appearance of pink is the endpoint.
Reaction:
Procedure:
Preparation of 0.01M Sodium hydroxide:
Weighed accurately about 0.4gm of Sodium hydroxide pellet in a clean 1000ml standard flask then completely dissolved with 100ml distilled water, and make up to 1000 ml with distilled water.
Standardisation of 0.01M sodium hydroxide:
Weighed accurately about 0.5gm of potassium hydrogen phthalate and transferred into a 1000ml conical flask. Then add 75ml of distilled water to dissolve and titrated with 0.01M sodium hydroxide solution using 0.1ml phenolphthalein as an indicator. The endpoint is the appearance of permanent pale pink colour.
Each ml of 0.01M Sodium hydroxide= 0.002042g of C8H5KO4
Assay of Chlorpheniramine maleate
Twenty tablets were weighed and grind into a fine powder. An amount of power equivalent to 200mg of chlorpheniramine maleate was weighed accurately into a 100ml standard flask, 70ml of neutral alcohol was added and shaken for about 20 min.
Then, the volume was made up to mark with neutral alcohol, mixed well and filtered using whatmann No 42 filter paper.
The first 10 ml portion of the filtrate was discarded. An aliquot of the drug solution containing 2.0-20.0 mg of chlorpheniramine maleate was measured accurately and transferred into a clean 100 ml conical flask and the total volume was brought to 10 ml with neutral alcohol.
Then 2 drops of 0.5% phenolphthalein indicator was added and the solution was titrated with standard 0.01M Sodium hydroxide solution until a permanent pink colour was obtained.
Each ml of 0.01M Sodium hydroxide= 0.002042g of C8H5KO4.
Report:
The molarity of 0.01M Sodium hydroxide=
The percentage purity of given Chlorpheniramine maleate tablet was found to be=
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