AbstractDuring investigation of DUP 996, a novel compound with potential memory‐enhancing properties, nine parallel forms of the Buschke Selective Reminding Test were required. Nine word lists were created using a previously published methodology and word pool. In order to assess the equivalence of these word lists, data on each of the nine test forms were obtained from 21 subjects who received a single placebo dose in closely controlled clinical trial conditions. Analysis of variance revealed between‐subject effect, confirming the large inter‐individual differences in performance which had been observed during testing. The subjects were categorized as poor or good performers, and in a subsequent analysis the test forms were not found to differ significantly within the groups, confirming the utility of the methodology and word pool for the creation of unmatched word lists of similar difficulty.
Falipamil (2-[3-[3-(3,4-dimethoxyphenetylmethylamino]propyl]-5,6- dimethoxyphthalamidine; 1) is a new specific bradycardic agent for the treatment of sinus tachycardia. Pharmacokinetics of falipamil in humans (n = 6) was determined in plasma and urine after iv administration of 100 mg (1.85 MBq) per person of 14C-labeled drug by liquid scintillation counting and by a specific, sensitive reversed-phase totally automated HPLC system with fluorimetric detection. Recovery of total radioactivity was 91.8 +/- 3.7%, with 68.2 +/- 4.3% in urine and 23.6 +/- 2.5% in the feces. The majority of radioactivity was excreted within 24 to 48 h. The parent drug, falipamil (1), and its N-desmethyl-metabolite (2), which is approximately 100 times less active than 1, contributed 14.1 +/- 1.6 and 4.5 +/- 0.7%, respectively, of the dose to urinary excretion. Plasma protein binding of 1 and 2 was 87.9 +/- 1.2 (concentration range: 2000-8000 ng/mL) and 89.7 +/- 0.5% (concentration range: 62.5-1000 ng/mL), respectively. Plasma concentrations of 1 peaked at 2 min at 724 +/- 173 ng/mL, declined biphasically, and were fitted to a two-compartment open model. Plasma concentrations of 2 were very low, in all cases ranging from 0 to 35 ng/mL. The dominant terminal half-life (beta-phase) of 1 from plasma was 1.8 +/- 0.6 h (range 1.4-2.9 h), mean residence time was 2.4 +/- 0.4 h, total body clearance was 1108.5 +/- 119 mL/min, and renal clearance was 117 +/- 20 mL/min. All parameters demonstrated very low intersubject variability.
The reliability of a direct, contact, mechanical method for the quantification of body sway is assessed. Methodological aspects in measurement of the eyes open/eyes closed ratio are also considered.
An open study to investigate the PAF-acether antagonist activity of Tanakan in healthy male volunteers examined the effect of a single 15-ml oral dose on ex vivo platelet aggregation induced by adrenaline, adenosine diphosphate (ADP), collagen or PAF-acether. Aggregometry was performed on platelet-rich plasma samples from blood taken 1 h before dosing with Tanakan and 2, 4 and 8 h after intake of Tanakan. Following dosing with Tanakan there was a reduction in platelet aggregation at all doses of PAF, with 1 microM ADP and adrenaline, the most significant decreases occurred with 75 nM PAF-acether 4 h after intake (p less than 0.05) and 300 nM PAF-acether 4 h (p less than 0.01) and 8 after intake (p less than 0.05). There were no concomitant changes in coagulation, skin bleeding time, haematological and biochemical laboratory tests, blood pressure or pulse. The results provide a possible explanation for the clinical efficacy of Tanakan in the treatment of peripheral vascular disease; they also confirm that a single oral dose of 15 ml Tanakan is well tolerated.
The tolerance and diuretic properties of torasemide after oral or intravenous administration to healthy volunteers were studied. Six groups, each of 6 subjects, were given single rising oral doses ranging from 10 to 100 mg; 8 subjects received ascending i.v. doses on alternate days, ranging from 2.5 to 80 mg. At the highest oral doses investigated (80 mg and 100 mg) a number of volunteers complained of cramps in the knees, calves and feet. These symptoms were generally of short duration. Similar effects were not encountered during the intravenous study. There were no significant changes in ECG. Some significant drug-related changes were encountered in the within-study biochemistry and haematology assessments. Torasemide proved to be a potent diuretic following oral administration at all the doses investigated and following intravenous administration at all doses except 2.5 mg. A linear relationship existed between the urine output and the logarithm of the dose, and both sodium and chloride excretion were linearly correlated with urine volume. The rate of potassium excretion was markedly lower than that of sodium and chloride and was linearly correlated with the logarithm of the urine volume. Torasemide was well tolerated from all perspectives studied. It showed a potent diuretic property, and was equally effective by the oral and intravenous routes.
The uptake of sulphamethoxazole, sulphadiazine, sulphamerazine, sulphanilamide, trimethoprim and brodimoprim by human peripheral blood leucocytes, has been investigated. High performance liquid chromatography (HPLC) was used to assay drug concentrations before and after incubation with leucocyte suspensions. Using radiolabelled material the intracellular localization of two of these compounds was also determined. The results indicated that all the investigated drugs were taken up by leucocytes. Differential studies demonstrated that mononuclear cells accumulated higher drug concentrations (0.13-0.55 microgram/10(7) cells), than resting neutrophils (0.02-0.26 microgram/10(7) cells) with the exception of sulphanilamide, which was taken up to a greater extent by neutrophils (0.75 microgram/10(7) cells). During neutrophil phagocytosis intracellular levels of all the drugs except brodimoprim increased from 3 to 130-fold as compared to resting neutrophils. The uptake of 14C-sulphanilamide and 14C-trimethoprim, in neutrophils and mononuclear blood cells, as assessed by measurement of the cell-associated radioactivity, correlated well with that determined by the HPLC procedure. In the intracellular localization studies 14C-sulphanilamide and 14C-trimethoprim exhibited similar distribution profiles. In neutrophils, 35-40% of radiolabelled drug was located in both the microsome and cytosol fractions whereas in peripheral blood mononuclear cells 40-60% was found in the cytosol and 10-20% in the microsome fraction. The results of this study suggest that, following activation, leucocytes may actively transport these drugs and release them locally at sites of infection. The ability of neutrophils to further concentrate the drugs during phagocytosis may result in reduced survival time of some ingested bacteria. These concepts may be important in designing treatment stratagems for intracellular pathogens.
A randomized controlled study in a family practice setting was conducted on the use of hypnosis in helping people quit smoking. In the hypnosis group 21 percent of patients quit smoking by the three month follow-up compared with 6 percent in the control group. By six months there were no significant differences between the two groups, and at one year 22 percent in the hypnosis group and 20 percent in the control group had quit. The only significant predictor of success with quitting was having a college education.
The novel benzodiazepine derivative, meclonazepam (3-methylclonazepam) has been found to be orally effective at high doses against all stages of schistosomiasis. Animals studies have shown it to have a high therapeutic index and a profile of behavioural activity typical of the benzodiazepines. The effects of single oral doses of meclonazepam, 1, 2 and 4 mg on central arousal, psychomotor performance and subjective mood were studied in two double-blind placebo controlled studies in healthy volunteers. In doses exceeding 1 mg, meclonazepam caused marked dose-related impairment in cognitive and psychomotor functions as well as shifts in mood reflecting sedation and ataxia. These effects were most prominent in the first 3 h after administration, with moderate sedation still present 6 h after the 4 mg dose. The implications of these findings for the use of benzodiazepine agents in the treatment of schistosomiasis are discussed.
A review of the published analytical methodology for the tricyclic antiviral (TAV) drugs is presented. While amantadine and rimantadine are the only two approved drugs for the prophylaxis and treatment of the influenza A virus, amantadine has also been approved for the treatment of Parkinson's disease. In addition, a few structurally related compounds are finding important clinical applications in other central nervous system-related disorders. To effectively evaluate the pharmacokinetics, biotransformations, stability, and other critical parameters that are necessary for pre-clinical and clinical studies, analytical methodology that conforms to the rigors of regulatory requirements must be developed and made available. This review discusses the analytical methods used in the determination of amantadine, rimantadine, tromantadine and memantine and the pre-clinical and clinical application of these techniques.
A sensitive and selective gas—liquid chromatographic method for the determination of plasma levels of mefloquine in human and dog plasma is described. The drug and internal standard were extracted from plasma at pH 9.0 into isopropyl acetate. After evaporation of the solvent, the residue was taken up in toluene and derivatised with heptafluorobutyrylimidazole. The derivative was quantified by gas—liquid chromatography on a 3% GC GE-SE30 column with electron-capture detection. The limit of detection for mefloquine in plasma was 10 ng/ml. The mean overall recovery from plasma was 102.7 ± 3.3%. The method was shown to be specific for mefloquine without any interference from endogenous compounds in plasma or from the drugs pyrimethamine and sulfadoxine (compounds often administered in combination with mefloquine).
The liniment used is a topical analgesic and anti-inflammatory preparation containing two active constituents, 3-phenylpropylsalicylate and ethyl-5-methoxysalicylate, in solution in isobutyl decanoate. It is known that 3-phenylpropylsalicylate is metabolised to salicylic acid and salicyluric acid and ethyl-5-methoxysalicylate is metabolised to 5-methoxysalicylic acid and gentisic acid. In the present study the separation of the salicylates and their metabolites was carried out on a Waters μBondapak C18 column using two different mobile phases, methanol—water (80:20) for the parent drugs and methanol—5% aqueous acetic acid (27:73) for their metabolites. The salicylates and their metabolites were detected by absorption at 310 nm. The limits of detection for parent drugs and metabolites were respectively 0.2 and 0.1 μg/ml in plasma, using a 1-ml plasma sample and a 20-μl injection from a reconstituted volume of 250 μl. Mean percentage coefficients of variation for intra-assay and inter-assay precision were between 3.3 ± 1.9% to 9.1 ± 3.7% and 6.8 ± 2.2% to 15.7 ± 10.1%, respectively. Linearity, as measured by the correlation coefficient of intra-assay linear regression curves, was better than 0.998 in all cases.