A specific gas chromatographic method for the detection of p-hydroxyamphetamine and p-hydroxynorephedrine in brain tissue.
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Amphetamine↗
Biomedical subjects
S Caccia
Publications and source records attributed to S Caccia.
Tissue catecholamines and daily rhythm of liver microsomal enzyme activity.
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Animals↗
Interaction of (+)-amphetamine with cerebral dopaminergic neurones in two strains of mice, that show different temperature responses to this drug.
1. (+)-Amphetamine sulphate elicits a dose-dependent hyperthermia in NMRI mice but it does not significantly increase the body temperature of C(3)H mice.2. When low doses of (+)-amphetamine are given, the body temperature of C(3)H mice decreases.3. (+)-Amphetamine decreases the noradrenaline concentration in the brain-stem and increases the homovanillic acid concentration (HVA) in the striatum of NMRI mice, but only slightly reduces the noradrenaline concentration and does not change the HVA concentration in the brains of C(3)H mice.4. The two strains appear to show a difference in the metabolism of dopamine in the striatum. The rates at which dopamine disappears from the tissue after blocking catecholamine synthesis with alpha-methyltyrosine and the rates at which HVA accumulates after blocking the active transport of this metabolite out of the brain with probenecid suggest that the turnover of dopamine is lower in C(3)H mice than in NMRI mice.
Animals↗
Propranolol does not alter flutoprazepam kinetics and metabolism in the rat.
The influence of propranolol on the disposition of flutoprazepam, a benzodiazepine derivative extensively biotransformed by hepatic microsomal oxidation, was evaluated in the rat. Propranolol was infused subcutaneously with osmotic minipumps (5 mg/day) to obtain steady-state concentrations of about 200 ng/ml. Flutoprazepam (5 mg/kg) was given intraperitoneally on the third day of propranolol infusion. There was some variability in flutoprazepam disposition, consistent with the concept of an extensive first-pass metabolism of high-extraction drugs. Propranolol had no significant effects on the kinetics of flutoprazepam or norflutoprazepam, an active metabolite possibly accounting for a substantial part of the parent compound's pharmacological and clinical effects. It was concluded that there is no evidence of any pharmacokinetic interaction between this beta-adrenoceptor blocker and flutoprazepam in the rat.
Animals↗
Kinetics and brain uptake of S 9795, a new xanthine derivate, in rats.
The relationships between plasma and brain concentrations of S 9795 and its main metabolites after single intravenous doses of S 9795 were examined in rats by high-performance liquid chromatography with UV detection. S 9795 disappeared from plasma and brain almost in parallel, with comparable elimination t1/2 of about 0.8 h, regardless of the dose administered. The volume of distribution was high (about 3 1/kg) but total clearance was also high (about 40 ml/min/kg) and this explains the relatively short plasma and brain t1/2 of the drug in the rat. Among the possible metabolites examined, the N-dearylated metabolite S 10238 rapidly appeared in both plasma and brain. Thereafter, S 10238 was likewise eliminated in parallel from both compartments, although at a slower rate (t1/2 of about 1.4 h) than its parent compound. Norcyclizine, a metabolite resulting from cleavage of the parent drug side-chain, was detected only in the brain and only at the highest dose tested. The brain AUC to plasma AUC ratio was slightly less than 1 for S 9795, about 0.1 for S 10238 and possibly more than 2 for norcyclizine, this latter being present in rat plasma at concentrations below the limits of sensitivity of the method (0.08 nmol/ml). The results indicate that S 9795 and some of its metabolites enter the central nervous system, although to different extents, and support the hypothesis that the lack of central effects of S 9795 is probably the consequence of the poor adenosine brain receptor antagonism by this compound.
Animals↗
Solid-phase extraction of piribedil and its metabolites from plasma and urine without and after deconjugation, by high performance liquid chromatography.
A new high performance liquid chromatographic procedure has been developed for the simultaneous quantification of piribedil (PD) and its three main basic metabolites in rat plasma and urine, without and after hydrolysis. The procedure relies on isolation of the compounds from plasma and urine constituents using the Sep-Pak C18 cartridge, with satisfactory recovery and specificity, and resolution by acetonitrile gradient elution on a C18 reversed phase column coupled to a UV detector monitored at 240 nm. The assay was linear over a wide range of concentrations for all compounds in both body fluids with mean within-day and day-to-day coefficient of variation (CV) and relative error (RE) generally below 10%. Plasma concentrations of PD and its metabolites at selected intervals and urinary recoveries of all compounds before and after enzymatic hydrolysis are presented.
Administration, Oral↗
[Pharmacokinetics of fenazepam and its metabolite 3-oxyfenazepam in animals of different species and in man].
It has been established that phenazepam is rapidly absorbed from the gastrointestinal tract of animals and man. The maximal concentrations of the unchanged drugs are reached 1, 0.5, 2 and 4 hours in rats, dogs, cats and man, respectively. The half-life of phenazepam in animal and human blood decreases in the following order: man greater than cat greater than dog greater than rat. The metabolite 3 + hydroxyphenazepam was identified in appreciable amounts in cat and rat blood.
Animals↗