Rhythmic Urinary Excretion of Amphetamine in Man

Beckett, A. H.; Rowland, M.

doi:10.1038/2041203a0

Cited by 71 publications

(28 citation statements)

References 8 publications

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“…Urinary recovery of amphetamine following administration of the enantiomers separately indicated that a higher percentage of ( -)-isomer was excreted unchanged. 3 However, since the excretion of amphetamine is known to be highly pH-dependent,2, 5 minordifferences in the excretion of separately administered enantiomers are difficult to interpret. Gunne 9 investigated the enantiomeric ratios in urine after administration of the racemate to 4 subjects using an analytical method which resolved the enantiomers by gas chromatography.…”

mentioning

confidence: 99%

Kinetics, salivary excretion of amphetamine isomers, and effect of urinary pH

Wan

Matin

Azarnoff

1978

Clin Pharma and Therapeutics

100

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Amphetamine was administered to healthy subjects as the racemic mixture and as (+)- and (-)-isomers under conditions of urine acidification and alkalinization. Plasma and saliva concentration of each isomer was measured and the kinetics of the individual isomers were determined. (+)-amphetamine was eliminated more rapidly than the (-)-isomer. The difference in half-life between isomers was maximal under basic urinary pH conditions. Saliva amphetamine levels were higher than plasma levels and in the postabsorptive phase were predictably proportional to plasma drug levels.

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mentioning

confidence: 99%

Kinetics, salivary excretion of amphetamine isomers, and effect of urinary pH

Wan

Matin

Azarnoff

1978

Clin Pharma and Therapeutics

100

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“…However if the urine is rendered acidic (pH ca 5-0) for the same period the proportion of unchanged drug excreted increases to 60-70%. If the urine is rendered alkaline (pH ca 8-0) this percentage falls to below 10% (Beckett & Rowland, 1964.…”

Section: Selection Of Drugs For Screeningmentioning

confidence: 98%

“…A further complication is the fact that the elimination of many drugs is markedly dependent on urinary pH and for some drugs on urine volume (Milne, Scribner & Crawford, 1958;Peters, 1960;Weiner & Mudge, 1964;Braun, Hesse & Malorry, 1963;Beckett & Rowland, 1964, 1965cAsatoor, Galman & others, 1965;Beckett & Wilkinson, 1965a). Since urinary pH and output fluctuate throughout the day, these parameters, in addition to the time factor, can influence substantially the concentrations of unchanged drug and of its metabolites in urine.…”

Section: Selection Of Drugs For Screeningmentioning

confidence: 98%

Routine detection and identification in urine of stimulants and other drugs, some of which may be used to modify performance in sport

Beckett

Tucker

Moffat

1967

Journal of Pharmacy and Pharmacology

186

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A general procedure for the analysis in urine of basic drugs (and their metabolites), some of which may be misused as stimulants in sport, has been developed. The techniques used include gas-liquid and thin-layer chromatography and linked gasliquid chromatography-mass spectroscopy. It is recommended that international control of drug-taking in sport be based primarily upon urine analysis by gas-liquid chromatography systems and also derivative formation followed by gas-liquid chromatography. The principles outlined in the procedure can be applied in a much wider forensic context.

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“…These phenomena are caused by changes in absorption (Adir & Barr 1977;Davenport 1966), distribution (Breiby et al 1983), metabolism (DiSanto & Wagner 1972;Jori et al 1973;Patel et al 1977;Radzialowski & Bousquet 1968;Roberts & Turnbull et al 1970), and elimination (Beckett & Rowland 1964;Koike et al 1984;Roberts & Denton 1980). Several antibacterial drugs such as amoxicillin (Roberts & Denton 1980), ampicillin (Breiby et al 1983), tetracycline (Adir & Barr 1977) and cinoxacin (Koike et al 1984) have demonstrated pharmacokinetic changes due to time of administration or posture.…”

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confidence: 95%

Effects of Time of Administration and Posture on the Pharmacokinetics of Cefprozil

Shyu

Gleason

Barbhaiya

1993

Clinical Pharmacokinetics

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The effects of time of administration, sleep and posture on the pharmacokinetics of cefprozil were evaluated in a single-dose 3-way crossover study. After a 6-hour fast, 12 healthy male volunteers received oral cefprozil 250mg at 1200h (treatment A), 1200h (treatment B) and 2400h (treatment C) with a 7-day washout interval between each treatment. During the study period, volunteers receiving treatment A remained in a sitting/standing position or were ambulatory, those receiving treatment B were in the supine position, and those receiving treatment C were sleeping. Blood samples were taken over an 8-hour period and the plasma samples were analysed for the concentrations of cefprozil by a high performance liquid chromatography-ultraviolet method. Plasma concentration vs time data were analysed using noncompartmental analysis methods. Mean peak plasma concentrations (Cmax) were 4.51, 5.02 and 4.91 mg/L for treatments A, B and C, respectively. Corresponding mean values of the area under the plasma concentration-time curve (AUC(0-infinity)) were 12.6, 12.6 and 14.2 mg/L.h, respectively. The mean half-life (t1/2) values were 1.30, 1.23 and 1.50 hours for treatments A, B and C, respectively. Mean AUC(0-infinity), Cmax and t1/2 values following treatment B were not significantly different from those of treatment A. However, the mean AUC(0-infinity) and t1/2 values of cefprozil following treatment C were significantly greater than those of either treatment A or B. The mean Cmax value following treatment C was not significantly different than that of either treatments A or B. From these results, it was concluded that posture has no effect on the pharmacokinetics of cefprozil.(ABSTRACT TRUNCATED AT 250 WORDS)

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Rhythmic Urinary Excretion of Amphetamine in Man

Cited by 71 publications

References 8 publications

Kinetics, salivary excretion of amphetamine isomers, and effect of urinary pH

Kinetics, salivary excretion of amphetamine isomers, and effect of urinary pH

Routine detection and identification in urine of stimulants and other drugs, some of which may be used to modify performance in sport

Effects of Time of Administration and Posture on the Pharmacokinetics of Cefprozil

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