Adrenaline determination

Adrenaline determined by the ferrous sulphate-citrate method (p. 20) with a washing with 10 ml of ether after development of colour. 

Various hydroxyl and amino derivatives of aromatic compounds are oxidized by peroxidases in the presence of hydrogen peroxide, yielding neutral or cation free radicals. Thus the phenacetin metabolites p-phenetidine (4-ethoxyaniline) and acetaminophen (TV-acetyl-p-aminophenol) were oxidized by LPO or HRP into the 4-ethoxyaniline cation radical and neutral V-acetyl-4-aminophenoxyl radical, respectively [198,199]. In both cases free radicals were detected by using fast-flow ESR spectroscopy. Catechols, Dopa methyl ester (dihydrox-yphenylalanine methyl ester), and 6-hydroxy-Dopa (trihydroxyphenylalanine) were oxidized by LPO mainly to o-semiquinone free radicals [200]. Another catechol derivative adrenaline (epinephrine) was oxidized into adrenochrome in the reaction catalyzed by HRP [201], This reaction can proceed in the absence of hydrogen peroxide and accompanied by oxygen consumption. It was proposed that the oxidation of adrenaline was mediated by superoxide. HRP and LPO catalyzed the oxidation of Trolox C (an analog of a-tocopherol) into phenoxyl radical [202]. The formation of phenoxyl radicals was monitored by ESR spectroscopy, and the rate constants for the reaction of Compounds II with Trolox C were determined (Table 22.1). 

Procedure Determine the angle of rotation of the freshly prepared 4% w/v solution of adrenaline in 1 M hydrochloric acid with the help of a previously checked polarimeter. The mean value of at least five similar determinations is employed in the calculation of the specific optical rotation. 

How would you carry out the determination of specific optical rotation of the following official compounds (f) Adrenaline, (ii) Betamethasone,... 

Although some steroids have been reported to reduce the toxic effects of some insecticides, the steroid ethylestrenol decreased the rate of recovery of depressed cholinesterase activity in disulfoton- pretreated rats (Robinson et al. 1978). The exact mechanism of this interaction was not determined. Ethylestrenol alone caused a small decrease in cholinesterase activity, and, therefore, resulted in an additive effect. Rats excreted less adrenaline and more noradrenaline when given simultaneous treatments of atropine and disulfoton compared with rats given disulfoton alone (Brzezinski 1973). The mechanism of action of disulfoton on catecholamine levels may depend on acetylcholine accumulation. In the presence of atropine, the acetylcholine effect on these receptors increases the ability of atropine to liberate catecholamines. 

In any setup, it is paramount that the electrodes get cleaned regularly. The minimum frequency, e.g., once a week, should be described in the instrument standard operation procedure (SOP), but for some methods or samples more frequent cleaning is necessary. An example is the determination of the enantiomeric purity of adrenaline in local anesthetic solutions. The samples are isotonic and contain high concentrations of local anesthetics (5—20mg/ml). The determination concerns very low concentrations of adrenaline (typically 5 pg/ml of 1-form and only a few percent of that of the d-form) and the samples are therefore injected undiluted. Furthermore, relatively high concentrations of cyclodextrin are present in the BGE. Eong sequences therefore require electrode cleaning for every sequence and this is thus described in the method procedure. ... 

Sanger-van de Griend, C. E., Ek, A. G., Widahl-Nasman, M. E., and Andersson, E. K. M. (2006). Method development for the enantiomeric purity determination of low concentrations of adrenaline in local anaesthetic solutions by capillary electrophoresis. /. Pharm. Biomed. Anal. 41, 77—83. 

Since the main clinical use for antisympathotonics is in the treatment of essential hypertension, such drugs will be discussed in Chapter 20 in more detail. The alkaloid reserpine from Rauwolfia serpentina was the first drug used clinically to reduce sympathetic tone. Reserpine reduce the ability of storage and release of various transmitters (adrenaline, noradrenaline, serotonine and dopamine) by an irreversible destruction of the axonal vesicle membranes. The duration of the reserpine effect is actually determined by the de novo synthesis of these structure. Beside various central side effects like sedation, depression, lassitude and nightmares the pattern of unwanted effects of reserpine is determined by the shift of the autonomic balance towards the parasympathetic branch myosis, congested nostrils, an altered saliva production, increased gastric acid production, bardycardia and diarrhea. As a consequence of the inhibition of central dopamine release, reserpine infrequently shows Parkinson-like disturbances of the extrapyramidal system. 

Figure 15.3 shows aqueous phase acylation of adrenaline in an injection with acetic anhydride. The reaction is carried out in the presence of aqueous sodium bicarbonate and is used in a gravimetric determination of (-) adrenaline in Adrenaline Injection BP. 

The analyte is loaded onto the gel in a buffer at ca pH 7.0 and the complex formed can then be broken down using a mildly acidic eluent such as 0.1 M acetic acid. This type of extraction has been applied to the determination of dopamine, adrenaline and noradrenaline in plasma and to the determination of the extent of reaction of glucose with serum albumin as a measure of glucose fluctuations with time in diabetics. 

Heart Direct effects on the heart are determined largely by receptors. Adrenaline increases the heart rate, force of myocardial contraction and cardiac output which is associated with increased metabolism by the myocardium, increased oxygen consumption and thus decreasing cardiac efficiency. 

A sensitive spectrophotometric method based on the strong absorption of the aminochrome-sodium bisulfite addition products (see Section IV, F) at ca. 350 m/x. has been described recently by van Espen128and Oesterling and Tse 277-278 for determining total catecholamines. While not as sensitive as the fluorimetric procedures, this method is considerably more sensitive than the older colorimetric methods based on the visible absorption peak of the aminochromes. Also, it does not have many of the disadvantages (e.g. costly equipment and unstable blanks) often associated with fluorimetric techniques. The basic procedure can be satisfactorily applied to the differential determination of mixtures of adrenaline, noradrenaline, dopamine, metanephrine, and normetanephrine.178... 

However, the question as to whether the first methylation step, the conversion from noradrenaline to adrenaline, is an active process over-all in the body should be susceptible of fairly easy study by repeating the experiments of Richter and Macintosh (12) and of Beyer and Shapiro (4) but administering noradrenaline instead of adrenaline. The urine-excreted compounds could be bioassayed after suitable hydrolysis and the relative amounts of noradrenaline and adrenaline in the hydrolyzate determined by using the differential activities of the two compounds on rabbit intestine and rat uterus as first reported by West (16). The differences between normal persons and those in successive stages of essential hypertension with regard to their abilities to conjugate noradrenaline and adrenaline and with regard to their abilities to transform the former into the latter surely should be a subject of precise chemical study in the near future. 

Monoamine oxidase inhibitors (MAOIs), which were amongst the first antidepressant drugs to be used clinically. They affect one or both of the brain monoamine oxidase enzymes that play a role in the metabolism of serotonin, noradrenaline, dopamine and adrenaline. MAOIs inhibit breakdown of the neurotransmitters important in determining mood, which results in the antidepressant effect. 

Persky, Harold, Chemical Determination of Adrenaline and Noradrenaline... 

Adrenalin, Chemical Determination, in Body Fluids and Tissues (Persky). 2... 

Fluids, Body, Chemical Determination of Adrenaline and Noradrenaline in (Persky). .. 2 57... 

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