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Biomedical subjects

T Taylor

Publications and source records attributed to T Taylor.

At least 181 records · Page 10Linked to original sources
PubMed1978

High-performance liquid chromatographic determination of benzodiazepines in human plasma.

A simple and sensitive method for determination of benzodiazepines in plasma has been developed using high-performance liquid chromatography in a reverse-phase mode. The method is illustrated by application to plasma samples containing diazepam and N-desmethyldiazepam at concentrations which would be encountered during therapy, with limits of detection of 10 ng/ml and 2 ng/ml for diazepam and N-desmethyldiazepam, respectively.

Chromatography, High Pressure Liquid↗
PubMed1978

Plasma concentrations of isosorbide dinitrate after administration of increasing doses of a sustained-release formulation to human subjects.

Plasma concentrations of isosorbide dinitrate have been measured after administration of increasing doses in the range 20--100 mg as sustained-release tablets (Isoket retard) containing 20 mg to human subjects. Means of peak concentrations of 4.2 ng/ml, 13.1 ng/ml, 20.7 ng/ml, 36.8 ng/ml, and 34.9 ng/ml were measured after doses of 20 mg, 40 mg, 60 mg, 80 mg and 100 mg, respectively. In the plasma of individual subjects, peak concentrations of isosorbide dinitrate increased in proportion to the dose administered. Areas under the plasma isosorbide dinitrate concentration-time curves also increased in proportion to the dose administered. Bioavailability parameters were better correlated to the dose over the range 20--60 mg than over the range 20--100 mg.

Adult↗
PubMed1977

Plasma concentrations, bioavailability and dissolution of chlorpropamide.

The bioavailability of chlorpropamide from two new formulations (Melitase tablets) has been compared to that from a reference formulation which is currently in clinical use as a hypoglycaemic agent. In both rate and extent of bioavailability, all three formulations may be considered equivalent, providing allowances are made for differences in drug content. With 95% confidence, the mean bioavailability of chlorpropamide from the new formulations was within about 16% of the mean from the reference formulaion, and formulation-related differences were not statistically significant. Although all three formulations were shown to have similar dissolution profiles, dissolution of chlorpropamide was pH-dependent in vitro. Dissolution was almost complete during 30 min at pH 7.2, but only 40%-60% had dissolved during 90 min at pH 2.0. A peak mean concentration of 22.7 mug/ml was reached 3 h after administration of 2 x 100 mg tablets of the new formulation and peak mean concentrations of 26.8 mug/ml and 27.4 mug/ml were reached 3 h and 4 hours after administration of one 250 mg tablet of the new formulation and one 250 mg tablet of the reference formulation respectively. Formulation-related differences of mean plasma concentrations (after scaling for equal doses of 250mg) were not significant and each formulation provided similar plasma concentrations at corresponding times after administration. Statistically significant subject-related differences in all the parameters of bioavailability were shown by analyses of variance.

Adolescent↗
PubMed1977

Plasma isosorbide dinitrate concentrations in human subjects after administration of standard and sustained-release formulations.

After sublingual administration of 5 mg of isosorbide dinitrate, mean plasma concentrations (+/-SD) peaked (8.9+/-3.1 ng/ml) at 15 min after dosing and declined with a half-life of 30 min. After oral administration of 5 mg, mean concentrations peaked (3.1+/-0.7 ng/ml) at 30 min and declined with a half-life of 40 min. After oral administration of 20 mg in a sustained-release tablet, mean concentrations initially peaked (1.4+/-1.2 ng/ml) at 40 min, declining to 0.9+/-0.5 ng/ml after 8 hr. Mean concentrations were maintained above half the mean peak level during 10 hr. Because of probable rapid first-pass metabolism, the bioavailability of isosorbide dinitrate after administration of the oral dose of the standard tablet was 58% of that from the sublingual dose, and the bioavailability from the sustained-release tablet was 47% of that from the sublingual dose of the standard tablet. The time course of mean plasma concentration data could be described by a one-compartment model; but a more complex model, taking the pass effect into account, probably is needed for a better description of the pharmacokinetics of isosorbide dinitrate.

Administration, Oral↗
PubMed1977

Plasma concentrations and bioavailability of clofibric acid from its calcium salt in humans.

The bioavailability of clofibric acid from formulations containing calcium clofibrate along and mixed with calcium carbonate (1:1 w/w) was compared to that from a standard clofibrate formulation in a crossover study in 12 human subjects. The 95% confidence intervals of bioavailability differences were such that they were unlikely to be detected in clinical practice; all three formulations may be considered bioequivalent, although the bioavailability rate was probably greater from the formulation containing calcium clofibrate alone. Peaks of mean concentrations of 80 +/- 13,67 +/- 16, and 64 +/- 18 microgram/ml +/- SD occurred after administration of 853 mg of clofibric acid calcium salt alone, 809 mg of clofibric acid calcium salt mixed with calcium carbonate, and 885 mg of clofibrate, respectively; mean concentrations declined from peak levels with half-lives of 15-17 hr.

Adult↗
PubMed1977

The relation of deviant symptoms and behaviour in a normal population to subsequent delinquency and maladjustment.

A survey of more than 6000 school children in 1961 established norms for symptomatology and behavior at ages 5-15. A follow-up to 1968 identified all children from the survey attending a child guidance clinic or appearing in court within that time. Those thus identified contained a significantly high proportion of boys who were reported as having more than 3 deviant items (i.e. occurring in approximately 10% of subjects in 1961). Specific health and behavioural items were found to have been reported in 1961 in proportions which were significantly different for children later appearing in child guidance clinic from those appearing in court. The amount of concern expressed by their parents over psychological and behavioural items distinguished court from clinic boys, while the concern shown by parents over items of physical health showed little difference in these 2 groups.

Adolescent↗
PubMed1977

Disposition of the hypoglycaemic sulphonylurea CS 476.

The disposition of radioactivity was studied after administration of a new oral hypoglycaemic agent, 14C-labelled CS 476, to rats, rabbits and dogs at a pharmacologically active dose level of 0.2 mg/kg and to human subjects at a therapeutic dose level of 5 mg. After oral doses, most of the drug was excreted in the faeces by rats and dogs and faecal radioactivity was obtained from biliary excretion. Rabbits and humans excreted most of the dose in urine. Unchanged CS 476 was the major radioactive component in the plasma of all the species during 6 hours after dosing, and was extensively bound to the plasma proteins. The half-life of CS 476 in plasma was 2 hours in dogs and humans, and 16 hours in rabbits. Drug accumulation did not occur in dog and rabbit plasma during a period of consecutive daily doses and the half-lives after the last of the repeated doses were similar to those found after single doses. In rats, plasma concentrations were relatively low, and did not reach the peak level found in female rats until 24 hours after dosing. CS 476 was extensively biotransformed. The apparent species-dependent disposition of CS 476 may explain differences in tolerance to chronic doses.

Administration, Oral↗
PubMed1977

Plasma concentrations of isosorbide dinitrate after oral administration of a sustained-release formulation to human subjects.

1. A peak of mean plasma concentrations of isosorbide dinitrate of 5.8 ng/ml was reached at 0.5 h after a single oral dose of 5 mg in a standard tablet formulation. Thereafter mean concentrations declined with a half-life of about 48 min. 2. A peak of mean concentrations of isosorbide dinitrate of 3.2 ng/ml was reached at 2--4 h after a single oral dose of 20mg in a sustained-realease capsule formulation (Iso Mack Retard). Thereafter mean concentrations declined by about twofold during 6 h and were still detectable at 12 h after dosing. 3. When corrected by dose/bodyweight variations, the mean area under the isosorbide dinitrate plasma concentration curve from the sustained-release capule was 76% of that from the standard tablet and this formulation-related difference in bioavailability was statistically significant (p less than 0.05). 4. The results showed that sustained-release formulation is a useful way to maintain plasma concentrations of isosorbide dinitrate for several hours.

Adult↗
PubMed1977

The distribution of radioactivity in pregnant rats after repeated oral doses of the diuretic agent Etozolin.

1. The distribution of radioactivity has been studied by whole-body autoradiography after administration of daily oral doses of (2-14C)-ethyl (Z)-(3-methyl-4-oxo-5-piperidino-thiazolidin-2-ylidene)acetate (etozolin, Gö 687, Elkapin) at a dose level of 100mg/kg to pregnant rats during the 10th to the 17th day of gestation. 2. After the last dose, most of the radioactivity was excreted rapidly and was mainly assoicated with the gastrointestinal and urinary tracts and kidneys of the mothers. 3. Maximal distribution in the mothers occurred at 3--6 h after the last dose, and radioactivity at these times was detectable also in the lungs, muscle mass, fat, mammary and uterine tissue, the reticuloendothelial system, placentae, some ducted and endocrine glands, and in blood, but not in brain or spinal cord. At 4 days, traces of radioactivity had persisted in kidneys, liver, lungs, thyroid and placentae. 4. Radioactivity was present in low and uniform concentrations in most foetal tissues such as the heart, lungs and lens and in even lower concentrations in the brains of the foetuses during 3--6 h after dosing, but was not detected in foetal tissues at 2 days. Concentrations of radioactivity in maternal tissues were at all times much higher compared with those in foetal tissues at corresponding times after dosing.

Administration, Oral↗
PubMed1977

Blood levels and bioavailability of ascorbic acid after administration of a sustained-release formulation to humans.

Plasma and whole blood concentrations of ascorbate have been measured after administration of 1000 mg of the vitamin as standard or sustained-release capsule formulations to human subjects. A peak of mean whole blood and plasma concentrations of 8.5 mug/ml and 5.7 mug/ml respectively (corrected for predose concentrations of "endogenous" ascorbate) occurred at 12 h and 6 h respectively after administration of a sustained-release formulation. After administration of a standard formulation, the peak of mean whole blood and plasma concentrations of 9.4 mug/ml and 8.6 mug/ml respectively occurred at 4 h. In whole blood, mean concentrations of ascorbate declined with a half-life of about 34 h. The bioavailability of ascorbate from the sustained-release formulation was 149% and 180% of that from the standard formulation by calculation from whole blood and plasma concentration data respectively.

Adult↗