High-performance liquid chromatographic analysis of amrinone and its N-acetyl derivative in plasma. Pharmacokinetics of amrinone in the dog.
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Biomedical subjects
Publications and source records attributed to J Edelson.
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A GLC method, employing a nitrogen-phosphorus-sensitive detector, is described for the analysis of mepivacaine, bupivacaine, etidocaine, lidocaine, and tetracaine in biological fluids. The method is simple, reliable, and sensitive, with a practical limit of sensitivity of approximately 2.5 ng/ml, well below therapeutic plasma levels. Extensive start-up procedures and sample preparation are not required.
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Cyclindole was extensively metabolized and eliminated primarily via the kidneys from most laboratory animals and man. Only in the dog was cyclindole a major urinary component. Cyclindole was metabolized by N-demethylation and/or hydroxylation. In studies utilizing radiolabeled drug, the primary urinary component was polar material which probably resulted from conjugation of the hydroxylated products. When desmethylcyclindole was administered to rats and dogs, large amounts of unchanged drug were administered to rats and dogs, large amounts of unchanged drug were recovered in the urine; there was no 3-aminotetrahydrocarbazole present. Significant amounts of urinary radioactivity were thought to represent hydroxylated and/or conjugated products. When 7-hydroxycyclindole was administered to dogs, only free parent drug was recovered from the urine; there was no evidence for N-demethylation. Flucindole, the 6,8-difluoro analog of cyclindole was metabolized by dog and man via N-demethylation with the formyl derivative being a probable intermediate in this reaction; both products were found in the urine. No didesmethyl metabolite was detected. In contrast to cyclindole, the N-oxide of flucindole was found in urine from both species. The route of elimination of oxarbazole and its metabolites was species specific: urinary excretion was 96.5, 38.7, 24.5, and 2.0% for the guinea pig, monkey, rat, and dog, respectively. The major urinary metabolite was O-demethyl oxarbazole; this metabolite was conjugated in all species except the guinea pig. The dog and monkey excreted small quantities of conjugated N-debenzoylated oxarbazole in urine. The profound changes in pharmacological activity that result from relatively small chemical modifications of the tetrahydrocarbazole nucleus make it likely that many further investigations of this class of compounds will be undertaken in the future.
The metabolism of trilostane, a novel inhibitor of adrenal steroidogenesis, was studied in the rat and monkey. In the rat, a peak blood level, equivalent to 2 microgram/ml of trilostane, was observed following a 25 mg/kg oral dose; excretion was mainly via the feces. In the monkey, the peak plasma level, equivalent to 15 microgram/ml, was observed 2 hr after a 20 mg/kg oral dose; elimination of radioactivity was predominantly in the urine. The five major metabolites of trilostane in monkey urine have been isolated and partially characterized. The primary metabolic pathways involved hydroxylation and glucuronide formation.
A high-pressure liquid chromatographic method for the analysis of rosoxacin and its pyridyl N-oxide metabolite in plasma and urine extracts is described. A statistical evaluation of the assay data has shown acceptable accuracy and precision for 0.5 to 25 microgram of rosoxacin or the metabolite per ml of plasma and for 2.5 to 60 microgram/ml of either compound in urine. The minimum quantifiable level for rosoxacin was 0.13 microgram/ml in plasma and 0.64 microgram/ml in urine; for the metabolite in plasma and urine, the corresponding values were 0.21 and 0.60 microgram/ml, respectively. The method was applied to plasma and urine from three dogs medicated orally with 5 mg/kg of rosoxacin. The pharmacokinetic parameters calculated for rosoxacin were: plasma halflife, 1.9 h; plasma clearance, 65 ml/min; volume of distribution, 11.31. The average total urinary excretion of rosoxacin as free and conjugated rosoxacin and its free N-oxide was 7.7 +/- 0.2% over the 48-h collection period.
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A sensitive and specific radioimmunoassay of dog and human plasma pentazocine is described. Rabbit antiserum and the second antibody method separated bound from free pentazocine. The radioimmunoassay employed an 125I-labeled radioligand and required extraction from the sample prior to quantitation. The method had a detection limit of approximately 200 pg/assay tube (1 ng/ml). The assay was used successfully to measure pentazocine in the plasma of beagle hounds given 0.3 mg of pentazocine/kg iv. The decline in plasma levels fitted a two-compartment body model with a 100-min mean overall half-life and a 3.2-liters/hr mean plasma clearance rate.
The analysis of plasma cyclazocine by two methods is described. The radioimmunoassay employed a 125I-labeled radioligand, rabbit antiserum, and sepration of bound from free cyclazocine with a second antibody. The radioimmunoassay was specific for cyclazocine and had a detection limit of approximately 20 pg/ml. The GLC method employed a mass spectrometer as the detector and had a detection limit of approximately 109 pg/ml. Both techniques had acceptable accuracy and precision when used to quantitate cyclazocine in dog and human plasma. The methods were used successfully to quantitate cyclazocine from beagle hounds receiving 0.5 mg of 3H-cylazocine/kg iv. The decline in plasma cyclazocine fitted a two-compartment body model with a mean plasma clearance rate of 39.2 liters/hr.
The blood levels, distribution and duration of action of ciprofibrate, an orally active hypolipidemic agent, was investigated in rats. Serum concentrations of 30 micrograms of ciprofibrate/ml are associated with significant reductions in both serum cholesterol and triglycerides in rats on a hyperlipidemic diet. Increasing the plasma concentrations of ciprofibrate to 69 micrograms/ml resulted in only a modest incremental reduction in serum lipids. The distribution of radioactivity from [14C]ciprofibrate within rat tissues was not affected by prior treatment for 14 days with ciprofibrate at either 1.5 or 3.0 mg/kg/day. Varying the dosage regimen of ciprofibrate at 30 mg/kg, with medication at intervals of one, 2 or 3 days resulted in similar peak plasma levels of about 300 micrograms/ml, 4 h after medication. The half-life of ciprofibrate, during the terminal disposition phase, was about 82 h. Levels of serum cholesterol remained suppressed up to 3 days after medication with ciprofibrate was discontinued; triglyceride levels returned to control values more slowly.
4-(p-Chlorophenylthio)butanol (W-2719) administered orally to rats and dogs is rapidly absorbed, metabolized and excreted. The only major biotransformation product found in blood was p-chlorophenylthioacetic acid (W-2683). No W-2719 or the intermediary p-chlorophenylthiobutyric acid (W-2718) could be found in plasma after oral administration of the drug. When W-2719 was given i.v. to dogs, both W-2719 and W-2718 appeared in plasma but each had a very short half-life of about 10 min. After an oral dose of W-2719 to dogs the plasma content of W-2683 peaked at 4-6 h, amounting to approximately 20% of the dose. More than 91% of the dose was excreted with 48 h, 83% in urine and 9% in feces. The predominant excretion product in urine was p-chlorothiophenol, most of which was excreted in a conjugated form. The other major urinary metabolite was W-2683, while smaller amounts of W-2718 and unchanged drug were also found. No significant effect of prolonged dosing of 14C-W-2719 to dogs was observed on plasma 14C levels, peak time, 14C half-life or excretion and composition patterns.
A high-performance liquid chromatographic method for the analysis of 1-ethyl-1,4-dihydro-4-oxo-1,8-naphthyridine-3,7-dicarboxylic acid (I) in plasma and urine is described. A statistical evaluation of the assay technique has shown acceptable accuracy and precision at concentrations as high as 2.0 microgram/ml of plasma or 29.0 microgram/ml of urine for samples augmented with 1. As little as 0.08 microgram/ml of I in plasma or 0.42 microgram/ml of I in urine were quantitatively determined. The mean relative error for the assay of unknown concentrations of I in plasma and urine was +/- 8% and +/- 3%, respectively. This method was used for the analysis of I in the plasma and urine of rhesus monkeys following oral administration of 200 mg/kg of nalidixic acid.
Plasma levels were determined frequently after single doses of perfluorooctyl bromide were administered to beagle dogs at doses of either 30.8 g/kg po or 3.9 g/kg intratracheally. The apparent first-order half-life during the terminal elimination phase was about 1 day after oral medication and about 7 days after intratracheal administration. Analysis of tissues revealed the highest concentrations of the compound in abdominal fat of dogs autopsied 4 weeks later.
A sensitive method is described for the radioimmunoassay of danazol in monkey and human plasma. Antiserum was developed in rabbits, and a second antibody was used to separate bound from free danazol. The radioimmunoassay was specific for danazol, and the limit of detection ranged from 1.4 to 2.8 ng/ml. Exogeneous danazol could be quantitated accurately in both monkey and human plasma. The radioimmunoassay results agreed with values obtained by inverse isotope dilution after intravenous administration of 14C-danazol to monkeys. The assay was used successfully to measure danazol in plasma from human volunteers receiving 200 mg of danazol.
A method is described for the radioimmunoassay of circulating levels of the pituitary inhibiting agent, danazol. An antigen for danazol was prepared by reacting a 17-carboxy-methyloxime derivative of danazol with bovine serum albumin. By immunizing rabbits with this antigen, antiserum was generated which shows excellent specificity for danazol relative to its known metabolites as well as to many natural steroids. A radioimmunoassay was developed, without using separation or extraction techniques, involving competition for the antiserum between danazol in plasma and 14C-danazol. This assay has been successfully used to measure danazol in a series of normal human subjects receiving the drug at either 100 or 200 mg b.i.d. for 2 weeks. A significant relationship was seen between dosage of danazol and plasma concentrations.
THC was neither ulcerogenic in 'semi-fasted' of 18-hour fasted rats following an oral dose of 100.0 mg/kg nor did it promote fecal blood loss (51Cr-labelled erythrocyte test) in the fasted rat after a dose of 200.0 mg/kg. On the contrary, 200.0 mg/kg of acetylsalicylic acid was ulcerogenic and caused fecal blood loss in the fasted rat. Neither substance caused mortalities at the doses tested.
N-(1, 1-Dimethylethyl)-N'-[2-(4-pyridinyl)-4-pyrimidinyl]urea, Win 40, 882, was eliminated from the blood stream of dogs by two apparent first-order processes with alpha- and beta-phase half-lives of 0.2 hr and 1.4 hr, respectively. Radioactivity of the administered dose was excreted by rats in the feces and via the kidneys; about 40-45% of the dose was recovered in the feces, with the remainder in the urine, over a six day period. One of the terminal methyl groups of the tert-butyl moiety of Win 40,882 is sequentially oxidized by the rat to the alcohol, aldehyde and carboxylic acid. In addition, some of the aldehyde was further metabolized to generate two different monohydroxylated aldehydic metabolites; these hydroxyaldehydes accounted for less than 10% of the dose administered. An unusual metabolic pattern was noted in the excretion of Win 40,882. Over 30% of the urinary metabolites contained the carboxaldehyde function; only8% of the urinary radioactivity was represented by the further oxidation of the aldehyde group to generate the carboxylic acid.
1. Benorylate was well absorbed in rabbits, but more slowly than an equimolar mixture of aspirin and paracetamol. 2. Benorylate was extensively hydrolysed and converted to the typical metabolites of aspirin and paracetamol by both neonate and mature rabbits. 3. Absorption of either aspirin-paracetamol or benorylate was slower in neonate rabbits than in adult rabbits. 4. The excretion rate in adult rabbits was faster, for both aspirin and paracetamol metabolites, than in neonate rabbits.