#ASSAY OF FUROSEMIDE

Aim: To report the amount of Furosemide present in the given tablet/powder/solution

.

Materials: Burettes, pipettes, beakers, glass rod, funnel etc

Chemicals:

Procedure:1 Sodium hydroxide, PHP, chloroform, furosemide drug, DMF, Phenolphthalein indicator

Procedure:2 Potasium Bromate,Potasium bromide,HCl,Methyl orange

Principle:

             It is assayed by alkalimetry. The sample is dissolved in Dimethyl formamide and titrated against standardized solution of sodium hydroxide using bromothymol blue solution as an indicator.

                 

Procedure:

Standardization of 0.1M Sodium Hydroxide

Weigh accurately 0.2gm of Potassium hydrogen phthalate (C₈H₅KO₄) in to a conical flask.

Dissolve it in 10ml of distilled water and add 2 drops of phenolphthalein indicator.

Titrate this solution with prepared 0.1M NaOH solution until a permanent pale pink colour was produced.  

           Each ml of 0.1M NaOH ≡ 0.02042 gm of C₈H₅KO₄.

  

Assay procedure:1

Weigh accurately about 0.5 g, dissolve in 40 ml of dimethyl formamide and titrate with 0.1 M sodium hydroxide using bromo thymol blue solution as indicator. Carry out a blank titration.

       1 ml of 0.1 M sodium hydroxide is equivalent to 0.03307 g of C₁₂H₁₁1ClN₂O₅S.

Calculations:

Standardisation of 0.1M  Sodium Hydroxide

S. No	Contents in the flask	Burette Reading		Volume Consumed	Indicator
		Initial	Final
1
2

Each ml of 0.1M NaOH≡ 0.02042 gm of C₈H₅KO₄

X ml of Y M of NaOH≡ gms of C₈H₅KO₄

Y =

Assay:

S. No	Contents of the flask	Burette reading		Volume consumed	Indicator
		Initial	Final
1

 1ml of 0.1M NaOH≡ C₁₂H₁₁1ClN₂O₅S.

X ml of Y M NaOH≡ Z gm of C₁₂H₁₁1ClN₂O₅S.

Z=

Procedure:2

Preparation of Bromate-Bromide mixture: (5Mm KBrO₃-50mM KBr)

0.835 of KBrO₃ and 6g of KBr in water and diluting to 1L in a volumetric flask

Assay:  A 10 ml aliquot of pure drug solution containing 2-20mg of Furosemide was accurately transferred into a 100mL titration flask,10ml of 2M HCl was added and titrated with bromated-bromide mixture using 2 drops of methyl orange indicator till the disappearance of Indicator colour. A blank titration was performed and the volume of titrant was substracted  from volume required  for the volume required for drug solution titration.

The amount of Furosemide in the measured aliquot was calculated from

      Amount(mg)=VM_WR/0.333

Where V=volume of Bromate-bromide consumed(ml)

       M_w=Relative molecular mass of drug

       R=Molarity of bromate-bromide mixture w.r.t KBrO₃

Percentage purity = Estimate amount / Weight of powder taken

Report: The percent purity of furosemide present in given sample is found to be ………………