Assay Of Furosimide

 

Aim: To carry out the Assay of Furosemide tablets.

Apparatus:

• Erlenmeyer flask.
• Volumetric flask
• Pipette
• Burette

Chemicals Required: 

• Furosimide
• Dimethyl formamide
• Sodium hydroxide
• Bromothymol blue indicator
• 0.1N oxalicacid
• Phenlophthalein indicator

Principle: 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 furosimide 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  120C for two hours dissolve in 75ml of carbon dioxide free water. Added 0.1ml of phenlophthalein solution and titrate with the sodium hydroxide until a permenant pink color is produced.

    Each ml of 0.1M NaOH equivalent to 0.02042g of potassium hydrogen phthalate.

Procedure: 

a) Assay Method by Neutralization Titration: 

Weighed and powdered 20tablets and weighed accurately about a quantity of powder equivalent to 0.5g and dissolve in 40ml of dimethyl formamide and titrate with 0.1 M sodium hydroxide using bromothymol blue as an indicator the end point shows the color 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 10minutes. 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 C₁₂H₁₁C₁N₂O₂S taking 580 as the maximum at about 271nm. 

 

 

 

Report: The given sample contains _________mg of furosemide.