Urinary excretion kinetics of amphetamine in man

Beckett, A. H.; Rowland, M.

doi:10.1111/j.2042-7158.1965.tb07575.x

Cited by 202 publications

(51 citation statements)

References 16 publications

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“…The general procedure adopted for diet and collection of urine was similar to that previously described by Beckett & Rowland (1965). The induction and maintenance of acidic urine was as described by Beckett & Brookes (1967).…”

Section: Studies In Manmentioning

confidence: 99%

The metabolism, distribution and elimination of chlorphentermine in man.

Beckett¹,

Belanger²

1977

Brit J Clinical Pharma

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I A gas-liquid chromatography procedure for the determination of chlorphentermine (I), N-hydroxychlorphentermine (II) and a,o-dimethyl-a-nitro-,-44-chlorophenyl)ethane (IV) in urine has been developed. Also methods are reported to determine conjugated II and the total N-oxidized metabolites of I, i.e. II, conjugated II, a,a-dimethyl-a-nitroso-3-(4-chlorophenyl)ethane (III) and IV in urine.2 The synthesis of ,ct-dimethyl-a-nitroso-f-(4-chlorophenyl)ethane (III) and its properties are reported. 3 The kinetics of urinary excretion of I and its metabolic products after the oral administration of I to a human subject on separate occasions have been studied. Under normal conditions of urinary pH, metabolism by N-oxidation was the main elimination route of I; acidifying the urine increased the urinary excretion of unchanged I at the expense of the N-oxidized products. 4 The importance of the N-oxidation metabolic route in the distribution of chlorphentermine (I) in man is discussed.

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Section: Studies In Manmentioning

confidence: 99%

The metabolism, distribution and elimination of chlorphentermine in man.

Beckett¹,

Belanger²

1977

Brit J Clinical Pharma

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“…If the urine is alkalinized by excessive intake of bicarbonate, then this free fraction can fall to less than 5%, which may potentially produce a negative urine screening test. 66 Oral fluid appears to be unaffected with regard to systemic intake of bicarbonate. Hence this matrix has advantages over urine testing in being less susceptible to adulteration.…”

Section: Detection Of Amphetamine Abusementioning

confidence: 99%

Screening for drugs of abuse: which matrix, oral fluid or urine?

Allen

2011

Ann Clin Biochem

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Urine is recognized as the prime matrix for drug test screening with well-established methods and testing protocols. Its major limitation is with regard to the inconvenience of sample collection and lack of integrity due to adulteration, dilution, drug spiking or sample exchange. The question is whether oral fluid, with its apparent better sample integrity, can replace urine for drug screening. This review examines the sample integrity problems and the advantages and limitations of oral fluid and urine in drug screening programmes. The variety of sample collection devices for oral fluid is shown to be a problem with recovery and detection for some drugs. This is examined in relation to the pharmacokinetics of drug metabolism and excretion in this matrix. Buccal contamination with drugs in oral fluid may also cause problems with interpretation. The clinical advantages of oral fluid analysis compared with urine testing are highlighted. Parent drugs are often found in oral fluid where only their metabolites may be found in urine, for example the benzodiazepines. 6-Monoacetylmorphine, an indicative marker of heroin, has a high prevalence in oral fluid from users of this drug but its detection in urine is limited due to its short half-life. Advances in analytical techniques, particularly chromatography linked to tandem mass spectrometry, are helping to promote oral fluid analysis. However, the lack of concordance studies examining both urine and oral fluid drug levels and kinetics in the clinical setting is of some concern.

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“…In order to determine the influence of urine pH on the plasma and renal elimination of acebutolol, four healthy male volunteers (three of whom had taken part in the previous study) each took 3 x 100 mg capsules of acebutolol (Sectral) on two separate occasions. On one occasion urine pH was maintained at around 5 by ammonium chloride ingestion, and on the other occasion at about 8 by sodium bicarbonate ingestion (Beckett & Rowland, 1965 The plasma elimination of acebutolol was studied in two of the subjects, and the results for subject 1 are shown in Figure 3. Following acebutolol (300'mg), the plasma level of the drug quickly declined between 4 and 12 h, having a half-life of 2.3 h when urine pH was around 5 and 2.7 h when urine pH was about 8.…”

Section: The Influence Of Ph On the Buccal Absorption And Plasma And mentioning

confidence: 99%

The influence of pH on the buccal absorption and plasma and renal elimination of acebutolol [letter].

Kaye¹,

Long²

1976

Brit J Clinical Pharma

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may be due to more rapid excretion and metabolism of proxyphylline since it is a more water soluble compound.It is difficult to assign a clinical significance to these results since figures are not available for the relative potencies of proxyphylline and theophylline as bronchodilators. Considering the three theophylline preparations, if the degree of broncho-dilatation is related to the concentration of theophylline, then it would seem that the sustained release preparation should produce a steadier, more prolonged effect, especially during the night.

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Urinary excretion kinetics of amphetamine in man

Cited by 202 publications

References 16 publications

The metabolism, distribution and elimination of chlorphentermine in man.

The metabolism, distribution and elimination of chlorphentermine in man.

Screening for drugs of abuse: which matrix, oral fluid or urine?

The influence of pH on the buccal absorption and plasma and renal elimination of acebutolol [letter].

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