Assay of furosemide: Medicinal Chemistry Practical
To carry out the Assay of furosemide tablets.
1.A textbook of Medicinal Chemistry-I,Pragi Arora,Varun Arora,Davinder Kumar,Page no:288,289.
- Indian Pharmacopoeia Volume III 2018,Page No:2899,2900.
Furosemide, dimethyl formamide, sodium hydroxide, bromothymol blue indicator,0.1N oxalic acid, Phenolphthalein indicator, conical flask, burette, beaker, funnel etc.
It is assayed by aqueous acid base titration between weak acid furosemide and strong alkali sodium hydroxide. In this assay protophilic solvent dimethyl formamide is used which enhances the acidity of furosemide so that it can be titrated with sodium hydroxide. To make the effect of acid impurities present negligible a solvent blank determination is carried out.
PREPARATION AND STANDARDIZATION OF STANDARD SOLUTIONS
a) SODIUM HYDROXIDE,XM
Solutions of any molarity xM may be prepared by dissolving 40x g of Sodium hydroxide in sufficient water to produce 1000ml.
b) STANDARDIZATION OF 0.1M SODIUM HYDROXIDE SOLUTION
Weighed accurately about 5g of potassium hydrogen phthalate previously dried at 1200C for two hours dissolve in 75ml of carbon dioxide free water. Added 0.1ml of phenolphthalein solution and titrate with the sodium hydroxide until a permanent pink color is produced.
Each ml of 0.1M NaOH equivalent to 0.02042g of potassium hydrogen phthalate.
a) ASSAY METHOD BY (NEUTRALIZATION TITRATION)
Weighed and powdered 20 tablets and Weighed accurately about a quantity of powder equivalent to 0.5g and dissolve in 40ml of dimethyl formamide and titrate with 0.1M sodium hydroxide using bromothymol blue as an indicator the end point shows the colour change from yellow to blue. Carry out a blank titration.
b) ASSAY METHOD BY (UV SPECTROPHOTOMETRY)
Weighed and powdered 20 tablets and Weigh accurately about a quantity of powder equivalent to 0.1g of furosemide and shake with 150ml of 0.1M sodium hydroxide for 10 minutes. Added sufficient 0.1M sodium hydroxide to produce 250ml and filter. Dilute 5ml to 200ml with 0.1M sodium hydroxide and measure the absorbance of the resulting solution at the maximum at about 271nm.Calculate the content of C12H11 ClN2O5S taking 580 as the value of A (1%, 1cm) at the maximum at about 271 nm.
The given sample contains …………………. mg of furosemide.
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