The analysis of solutions of epinephrine and norepinephrine*

Welsh, Llewellyn H

doi:10.1002/jps.3030440815

Cited by 30 publications

(5 citation statements)

References 12 publications

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“…The procedure took about 15 min. Details of the products formed with some catechol amines, usually 3-O,4-O,N-triacetyl derivatives, are described by Welsh (1955).…”

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confidence: 99%

The Estimation of Small Quantities of 3,4‐dihydroxyphenylethylamine in Tissues

Laverty

Sharman

1965

British Journal of Pharmacology and Chemotherapy

149

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Several methods have been used to estimate small amounts of 3,4-dihydroxyphenylethylamine (dopamine) which occur in many plant and animal tissues. The biological assay of dopamine is, by comparison with that of other catechol amines, relatively insensitive. The pressor effect of dopamine on the blood pressure of the rat and the depressor effect observed on the blood pressure of the guinea-pig have been used to assay dopamine extracted from the splenic nerve and stellate ganglion of the ox (Schumann, 1956). These methods are suitable for microgram quantities of dopamine.Of the chemical methods which are applicable to the estimation of dopamine only those involving the formation of a fluorescent derivative are likely to be sensitive enough to estimate the small amounts of dopamine occurring in some tissues. The main fluorimetric methods are based on two chemical reactions.

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“…The procedure took about 15 min. Details of the products formed with some catechol amines, usually 3-O,4-O,N-triacetyl derivatives, are described by Welsh (1955).…”

mentioning

confidence: 99%

The Estimation of Small Quantities of 3,4‐dihydroxyphenylethylamine in Tissues

Laverty

Sharman

1965

British Journal of Pharmacology and Chemotherapy

149

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“…Alternative methods of estimation, whereby acetyl-metanephrine and acetyl-normetanephrine were converted to, fluorescent lutine derivatives (Brunjes et al, 1964) proved satisfactory. According to Welsh (1955), acetylation of the catecholamines occurs on the phenolic hydroxyls and the amino nitrogen, the formed ester groups being more readily hydrolysed than the amide linkage. Since hydrolysis of substituents on the catechol nucleus is a necessary preliminary to coupling with ethylenediamine (Weil-Malherbe & Bone, 1952) the phenolic acetyl groups cannot contribute to the alteration in fluorescence produced by acetylation.…”

Section: Discussionmentioning

confidence: 99%

A method for the estimation of the catecholamines and their metabolites in brain tissue

Crawford

Yates

1970

British J Pharmacology

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A method is described whereby the catecholamines, their precursors and metabolites may be estimated in the same brain sample. The method, outlined below, was rigorously tested in pure solution before being applied to the estimation of the catechol and methoxyamines in extracts of rat brain. (i) The brain tissue was homogenized in perchloric acid and the perchloric acid removed as its insoluble potassium salt. (ii) The acid metabolites of the amines were extracted from the acidified extract into ethyl acetate. (iii) After extraction with ethyl acetate, the aqueous extract was treated with acetic anhydride and sodium hydrogen carbonate and the acetylated derivatives of the amines extracted into dichloromethane. (iv) The aqueous solution remaining after extraction with dichloromethane contains the acetylated amino‐acids. Acetyl‐dopa could be extracted into dichloromethane only after acidification of this aqueous solution. The acetyl‐dopa in this dichloromethane extract could be estimated fluorimetrically. (v) The dichloromethane extract containing the acetylated amines was chromatographed on paper in the organic phase of a mixture of toluene: ethyl acetate: methanol: water, 10: 1: 5: 5. (vi) The acetylated amines were eluted and estimated fluorimetrically. A new method was developed for the estimation of 3‐methoxytyramine and its acetylated derivative. The reproducibility of the method was demonstrated by the consistent estimates obtained for the concentrations of noradrenaline, dopamine and 3‐methoxytyramine in whole rat brain. Adrenaline and metanephrine were not detected. The concentration of normetanephrine in rat brain was at the limit of detection of the method. Although the estimation for the levels of endogenous amines in whole rat brain were consistent, the recoveries of exogenous amines taken through the procedure were low and very variable. Control experiments demonstrated that the exogenous amines were lost at the perchloric acid extraction stage of the procedure.

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“…The British Pharmacopoeia (1968 and1973) adopted the method of Welsh (1955) for the determination of (-)-adrenaline in adrenaline injection B.P. and adrenaline solution B.P.…”

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confidence: 99%

“…of the triacetyl derivative(Welsh, 1955) = -95.3". of the triacetyl derivative(Welsh, 1955) = -95.3".…”

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confidence: 99%

A spectropolarimetric assay of (−)-adrenaline in compendial formulations

Davidson

1979

Journal of Pharmacy and Pharmacology

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A method is described for the determination of (-)-adrenaline in certain formulations containing adrenaline hydrogen tartrate at concentrations down to 0.18 mg ml-l(l: 10 OOO adrenaline). The assay is based upon a spectropolarimetric measurement at 249 nm of sample solutions, suitably treated to remove interfering substances. The rotation of the sample solutions is corrected for the rotation of the tartaric acid species which is determined by a difference rotation measurement on equimolar sample solutions at pH 1.1 and pH 5.6. The concentration of (-)-adrenaline in the sample is calculated from the net rotation at 249 nm due to the (-)-adrenaline and the total concentration of adrenaline (( +)-and (-)-isomers) determined by a published spectrofluorimetric method. The assay is specific for (-)-adrenaline in the presence of (+)-adrenaline, (+)-tartaric acid, adrenaline sulphonic acid and low levels of adrenochrome.

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The analysis of solutions of epinephrine and norepinephrine*

Cited by 30 publications

References 12 publications

The Estimation of Small Quantities of 3,4‐dihydroxyphenylethylamine in Tissues

The Estimation of Small Quantities of 3,4‐dihydroxyphenylethylamine in Tissues

A method for the estimation of the catecholamines and their metabolites in brain tissue

A spectropolarimetric assay of (−)-adrenaline in compendial formulations

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