antihypertensive drugs

QUANTITATIVE ANALYSIS OF ANTI-HYPERTENSIVE DRUGS

• Guided by: Mr. Keyur B. Ahir Mr. Falgun Mehta Pharm. Analysis

• Presented by: Shweta Singh M.Pharm Sem - II Pharm. Analysis II

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CONTENTS

NUMBER DRUG/FORMULATION

1 ATENOLOL

2 LABETALOL HYDROCHLORIDE

3 LABETALOL TABLET

4 PRAZOSIN HYDROCHLORIDE

5 PRAZOSIN TABLET

2

ATENOLOL

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Description – A white or almost white powder. Atenolol contains not less than 99.0 per cent and not more than

101.0 per cent C14H22N2O3 calculated on the dried basis.

ASSAYPRINCIPLE:

POTENTIOMETRY:

• A convenient and useful method of determining the equivalence point of a titration, i.e the point at which the stoichiometric analytical reaction is complete.

• If an indicator electrode, sensitive to the concentration of the chemical undergoing titrimetric reaction, and a reference electrode, whose potential is not sensitive to any dissolved chemical in solution, are immersed in the solution under examination to form a galvanic cell, the potential difference between the electrodes may be sensed by a simple potentiometer

• If a graph of the variation of potential difference is plotted as a function of the quantity of the titrant added, a sigmoid curve results with a rapidly changing portion in the vicinity of the equivalence point. The mid - point of this linear vertical portion or the inflection point may taken as the end - point of the titration.

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PROCEDURE

• Weigh accurately about 0.2 g

• Dissolve in 80 ml of anhydrous glacial acetic acid.

• Titrate with 0.1 M perchloric acid, determining the end-

point potentiometrically.

• Carry out a blank titration.

• 1 ml of 0.1 M perchloric acid is equivalent to 0.02663 g of

C14H22N2O3.

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LABETALOL HYDROCHLORIDE

Description - A white or almost white powder or granules.Labetalol Hydrochloride contains not less than 98.5 per cent and not more than 101.0 per cent of calculated C19H24N2O3,HCl on the dried basis.

ASSAYPRINCIPLE:

• Potentiometry:


• If an indicator electrode, sensitive to the concentration of the chemical undergoing titrimetric reaction, and a reference electrode, whose potential is not sensitive to any dissolved chemical in solution, are immersed in the solution under examination to form a galvanic cell, the potential difference between the electrodes may be sensed by a simple potentiometer

• If a graph of the variation of potential difference is plotted as a function of the quantity of the titrant added, a sigmoid curve results with a rapidly changing portion in the vicinity of the equivalence point. The mid - point of this linear vertical portion or the inflection point may taken as the end - point of the titration. 7

8

PROCEDURE

• Weigh accurately about 0.2 g.

• Dissolve in 10 ml of anhydrous formic acid and 40 ml of acetic

anhydride.

• Titrate with 0.1 M perchloric acid, determining the end-point

potentiometrically



C19H24N2O3,HCl.

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LABETALOL TABLET ASSAYPRINCIPLE : Uv spectrophotometry. PROCEDURE :• Weigh and powder 20 tablets. • Weigh accurately a quantity of the powder containing about 0.5 g of

labetalol hydrochloride.• Shake with 200 ml of 0.05 M sulphuric acid for 30 minutes.• Dilute to 250.0 ml with 0.05 M sulphuric acid, mix and filter. • Dilute 10.0 ml of the filtrate to 250.0 ml with the same solvent and measure

the absorbance of the resulting solution at the maximum at about 302 nm.• Calculate the content of C19H24N2O3, HCl taking 86 as the specific

absorbance at 302 nm.

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Description - A white or almost white powder; odourless or almost odourless.Prazosin Hydrochloride contains not less than 98.5 per cent and not more than 101.0 per cent of C19H21N504, HCl calculated on the anhydrous basis.

PRAZOSIN HYDROCHLORIDE

ASSAYPRINCIPLE:

• Potentiometry:


• If an indicator electrode, sensitive to the concentration of the chemical undergoing titrimetric reaction, and a reference electrode, whose potential is not sensitive to any dissolved chemical in solution, are immersed in the solution under examination to forma galvanic cell, the potential difference between the electrodes may be sensed by a simple potentiometer

• If a graph of the variation of potential difference is plotted as a function of the quantity of the titrant added, a sigmoid curve results with a rapidly changing portion in the vicinity of the equivalence point. The mid - point of this linear vertical portion or the inflection point may taken as the end - point of the titration.

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PROCEDURE :

• Weigh accurately about 0.35 g,

• Dissolve in 20 ml of anhydrous formic acid and 30 ml of

acetic anhydride.

• Titrate with 0.1 M perchloric acid, determining the end

point potentiometrically.



C19H21N504, HCl.

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PRAZOSIN TABLET ASSAYPRINCIPLE: liquid chromatography.

• Liquid chromatography (LC) is a separation technique

based on the difference in the distribution of components

between two non-miscible phases in which liquid mobile

phase elutes through a stationary phase in a column.

PROCEDURE:

• Determine by liquid chromatography.

Test solution :- • Weigh and powder 20 tablets. • Shake a quantity of the powdered tablets containing about 2 mg of

prazosin with 100 ml in a mixture of 96 volumes of methanol, 2 volumes of glacial acetic acid and 2 volumes of water for 30 minutes, centrifuge and use the supernatant liquid.

Reference solution :-• A 0.0022 per cent w/v solution of prazosin hydrochloride RS in a mixture

of 96 volumes of methanol, 2 volumes of glacial acetic acid and 2 volumes of water.

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CHROMATOGRAPHIC SYSTEM• A stainless steel column 20 cm x 4 mm, packed with porous silica

particles, (5 μm),

• Mobile phase: 0.01 per cent w/v solution of diethylamine in a mixture of 96 volumes of methanol, 2 volumes of glacial acetic acid and 2 volumes of water,

• Flow rate. 1 ml per minute,• Spectrophotometer set at 254 nm,• A 20 μl loop injector.

Calculate the content of C19H21N5O4 in the tablets.15

SUMMARY

NUMBER DRUG/FORMULATION PRINCIPLE

1 ATENOLOL POTENTIOMETRY

2 LABETALOL HYDROCHLORIDE POTENTIOMETRY

3 LABETALOL TABLET UV SPECTROPHOTOMETRY

4 PRAZOSIN HYDROCHLORIDE

POTENTIOMETRY

5 PRAZOSIN TABLET

LIQUID CHROMATOGRAPHY

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Reference :

• Government of India Ministry of Health and Family Welfare Indian pharmacopeia 2007 and 2010 published by the controller of publications Dehli.

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