analysis of barbiturates

05/02/2023VIKAS COLLEGE OF PHARM

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ANALYSIS OF BARBITURATES

BY @@@ Mr.S @@@ Pharmaceutical Analysis & Quality Assurance, Vikas College Of Pharmacy, Vissannapeta.

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VIKAS COLLEGE OF PHARMACY

CONTENTS INTRODUCTION - DEFINITION - HISTORY - ADVERSE EFFECTS - CLASSIFICATION - MECHANISM OF ACTION ANALYSIS OF BARBITURATES - COMMON METHODS AS PER I.P - QUALITATIVE ANALYSIS - QUANTITATIVE ANALYSIS CONCLUSION REFERENCES

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INTRODUCTION DEFINITION “The drugs that acts as a central nervous system

depressants and for that reason they can induce a spectrum of reasons are called as the Barbiturates”

They are any class of sedatives and sleep inducing drugs derived from barbituric acid which means that they can cause sleep

Synonyms: Barbs, Downers, Sleepers, Red Dolls. HISTORY These are introduced before 1904,primarily they are

called as Dietheyl-Barbituric Acids. In 20th century, 2,500 barbiturates were synthesised. 50 of which were eventually employed clinically for

treating insomnia.


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o ADVERSE EFFECTS

Short Term Effects Slurred Speech Confusion Disorientation

Long Term Effects Coma Depression Death

o CLASSIFICATION

o Long Acting Barbiturates (Anti-Convulscents): Phenobarbitol,Mephobarbitolo Short Acting Barbiturates (Hypnotics): Pentobarbitol,Amobarbitolo Ultra Short Acting Barbiturates (Anaesthetics): Thiopentol,Methohexitol

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MECHANISM OF ACTION

Barbiturates acts on the channel modulatory site of GABAA receptor and potentiate the GABA mediated inhibitory effects by “increasing the duration of chloride channel opening.”

At higher concentrations, barbiturates directly increase chloride ion conductance i.e., they exhibit a GABA facilitatory action.

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ANALYSIS OF BARBITURATES COMMON METHODS AS PER I.P:- QUALITATIVE ANALYSIS:A) Nitrogenous Substituted Barbiturates: Dissolve 5mg of the substance under examination in 3ml

of a hot 0.2%w/v solution of cobaltus acetate in methanol,add 5mg of finely powdered sodium tetraborate and boil,a blue violet colour is produced.

B)Non-Nitrogenous Substituted Barbiturates: Dissolve 5mg of the substance under examination in 3ml

of methanol, add 0.1ml of solution containing 10%w/v of cobaltus nitrate and 10%w/v of calcium chloride, mix and add with shaking 0.1ml of dilute NaOH solution a violet blue colour and a precipitate are produced.

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QUANTITATIVE ANALYSIS Method: TLC Mobile Phase: chloroform : ethanol : strong ammonia solution (80:15:05) Test Solution: A 0.1% w/v solution of the substance in ethanol

(95%). Reference Solution: A 0.1% w/v solution of the corresponding

reference substance in ethanol (95%). Procedure :1. Apply to the plate 10µl of each solution.2. Allow the mobile phase to raise 18cm.3. Remove the plate ,allow to dry.4. Examine the plates under UV-Light at 254nm.5. The principal spot in the chromatogram obtained with the test

solution corresponds to that in the chromatogram obtained with the reference solution.


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STANDARD RF VALUES OF BARBITURATES (TLC):

Amobarbitol – 0.4 Allobarbitol – 0.31 Butobarbitol – 0.39 Cyclobarbitol – 0.35 Methyl pheno b – 0.41 Pentobarbitol – 0.44 Phenobarbitol – 0.29 Secobarbitol – 0.42 Vinybital – 0.4

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QUALITATIVE ANALYSIS Qualitative Analysis of the barbiturates includes Barbiturates are prepared commercially as sodium salts

readily soluble in water or saline Colour – Yellowish or White Taste – Bitter Odour – Faint Garlic Odour

pH – 7.8 to 12.4 Incompatible for mixture with acidic solution of ringer

lactate. Decrease in alkalinity of solution by precipitation At room temperature stable for 6 days

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QUANTITATIVE ANALYSIS Quantitative Analysis of barbiturates includes Titrimetric Methods Direct Titration Indirect Titration…..etc.. Spectroscopy UV-Spectroscopy IR-Spectroscopy…….etc.. Chromatography Paper Chromatography Thin Layer Chromatography……etc.. Miscellaneous LC-MS GC-MS…….etc..

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TITRIMETRIC ESTIMATION OF ALLOBARBITAL

Allobarbital can be estimated by using acid-base titration

Dissolve 5mg of the allobarbital under examination in 3ml of a hot 0.2%w/v solution of cobaltus acetate in methanol.

Add 5mg of finely powdered sodium tetraborate and boil.

A blue violet colour is produced.

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SPECTROSCOPIC ESTIMATION OF CYCLOBARBITAL

Cyclobarbital can be estimated by the IR-Spectroscopy.

The sample of the cyclobatrbital is prepared by mixing 100mg of drug with the 100ml of the methanol (95%).

The sample is passed through the IR-Spectrophotometer and the principal peaks are observed at wavenumbers 1712,1684,1670,1770 cm-1

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ESTIMATION OF SECOBARBITAL BY TLC Method: TLC Mobile Phase: chloroform : ethanol : strong ammonia

solution (80:15:05) Test Solution: A 0.1% w/v solution of the substance in

ethanol (95%). Reference Solution: A 0.1% w/v solution of the

corresponding reference substance in ethanol (95%). RF Value of the secobarbital can be estimated by using

formula

Rf =

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Procedure :1. Apply to the plate 10µl of

each solution.2. Allow the mobile phase to

raise 18cm.3. Remove the plate ,allow to

dry.4. Examine the plates under

UV-Light at 254nm.5. The Rf value of the

secobarbital was found to be 0.42

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LC-MS ESTIMATION OF PHENOBARBITAL General procedure involved in estimation of

Phenobarbital by using LC-MS.

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CONCLUSION

I here by conclude that there is a much necessity for the study of analytical methods of Barbiturates as they are widely used class of drugs as Sedatives and Hypnotic agents……..

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REFERENCES• The Indian Pharmacopoeia1996

• P. D. Sethi, “Quantitative Analysis of Drugs in Pharmaceutical

Formulations”,.

• B. Morelli, J. Pharm. Biomed. Anal.,1989, 7, 577.

• P. B. Issopoulos, Acta. Pharm. Hung.,1992, 6, 3138.

• M. Knochen, J. Giglio and B.F. Reis, J. Pharm. Biomed. Anal.,

2003, 33, 191.• K.A Connors :Text book of Pharmaceutical Analysis,Third

edition,Page no:(62-63• Higuchi,Beckmman&Hassan :Pharmaceutical Analysis,second

editiom,Page no:(137-157)


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analysis of barbiturates

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