Disposition and metabolism of codorphone in the rat, dog, and man.

The disposition and metabolism of codorphone, 17-cyclopropyl-methyl-4,5 alpha-8 beta-ethyl-3-methoxymorphinan-6-one (I), a new narcotic antagonist, analgesic agent, have been studied in the rat, dog, and man. Rats and dogs were given single 100- and 50-mg/kg po doses, respectively, of I-3H; human volunteers received single 10- to 30-mg doses of unlabeled I po. The compound appeared to be well absorbed in the three species. In rats the highest levels of radioactivity were in liver, adrenals, kidneys, spleen, and lungs. Excretion was primarily fecal in rats and dogs. In man about 50% of the dose appeared in the 24-hr urine. I was about 95% metabolized by each species. The major metabolites in rats resulted from 3- and/or 17-dealkylation. Metabolism in dogs was characterized primarily by 17-dealkylation. The major pathways of I metabolism in man were 17-dealkylation and 6-reduction. In the three species significant glucuronic acid conjugation of metabolites occurred.

Methodology for the identification of the urinary metabolites of the analgesic-narcotic antagonist, codorphone, by gas chromatography mass spectrometry.

Methodology is presented for the identification of codorphone and its metabolites in urine samples using gas chromatography mass spectrometry. The procedure focuses on the clean-up of biological samples and a derivatization technique suitable for these samples. Sep-Pak C-18 cartridges were employed in the clean-up procedure permitting the biological sample to be derivatized in a relatively small volume of reagents. The derivatization procedure incorporated a one-step trimethylsilyloxime reaction to prevent enol formation while simultaneously derivatizing free hydroxyl groups with the excess trimethylsilylimidazole present in the reaction mixture. This was followed by the addition of BSTFA directly to this reaction mixture to complete derivatization of any metabolites possessing dealkylation of the nitrogen. Using this derivatization scheme, synthetic metabolites were analyzed by gas chromatography mass spectrometry, and their mass spectra were characterized emphasizing the diagnostic fragment ions observed in the spectra. To illustrate the usefulness of this methodology, a urine sample obtained from a dog that had been dosed with codorphone was analyzed by gas chromatography mass spectrometry, and the metabolites were identified by comparison to the mass spectra of the synthetic derivatives.

Pharmacological study of broperamole, a chemical novel antiinflammatory compound.

N-3[5'-(3"-Bromophenyl)-2'H-tetrazole]propionyl piperidine (broperamole) was shown to elicit potent antiinflammatory activity following systemic administration to rats in acute and subchronic studies. The compound demonstrated systemic antiinflammatory activity 5-6 times that of phenylbutazone. Toical antiinflammatory activity was also demonstrated which was less than that of hydrocortisone but still should have clinical utility. Antipyretic activity, without effect on normal body temperature, was observed. Analgesic activity was not evidenced. Only at very high doses was gastric irritation noted; therefore, at anticipated human dose level, gastrointestinal toxicity in man should not occur.

Influence of broperamole, a new antiinflammatory agent, on gastrointestinal microbleeding in the dog.

59Ferrous sulfate was administered i.v. to 12 male beagles. Beginning 11 days later, gastrointestinal microbleeding was determined by comparison of the 59Fe specific activities of 24-h stool collections and of whole blood. During the following 48-day period the dogs received p.o. twice daily a placebo, two tablets containing 650 mg of acetylsalicylic acid (ASA), 22 mg/kg of phenylbutazone, or 24 mg/kg of N-2-[5'-(3"-bromophenyl-2'H-tetrazole]propionyl piperidine (broperamole) in four 7-day tratment periods (each of which was preceded by a 5-day period of no treatment) in complete crossover fashion. Average daily fecal blood volumes of 2.55 ml, 1.94 ml, 0.54 ml, and 0.48 ml were observed after treatment with ASA, phenylbutazone, broperamole, and placebo, respectively. The influence of ASA and phenylbutazone on gastrointestinal microbleeding was statistically greater than that of broperamole, which was equivalent to placebo.

Rates of release of subcutaneously injected antigens in the rat. Comparison of an aqueous preparation with two alum-precipated preparations.

Release of antigen E-125 I from the site of subcutaneous injection in male rats was delayed significantly when either of two alum-precipitated preparations containing 1.0-1.2 mg of Al/ml was administered rather than an aqueous preparation. The rates of 125I excretion were similarly influenced being statistically slower through the first week after single doses of the alum-precipitated preparations. The results of these studies strongly support the view that alum-precipitated vaccines offer more protection from system reactions than aqueous vaccines.

Fate of 14C-3-methylamino-1,2,3,4-tetrahydrocarbazole hydrochloride in rats and dogs.

The fate of 14C-3-methylamino-1,2,3,4-tetrahydrocarbazole hydrochloride, a potential psychotherapeutic agent, was studied in rats and dogs. Rats were given a single oral or intraperitoneal dose while dogs received the drug either orally or intravenously. Radioactivity in plasma samples and excreta was determined by liquid scintillation counting. In addition, 14C-levels in various rat tissues were estimated. The drug appeared to be well absorbed in both species. 14C-levels were highest in liver and lung and lowest in plasma. Excretion was primarily urinary and was more complete within the first 96 hr in the rat than in the dog, which suggested a longer 14C-half-life in the dog. No evidence was seen that the drug was demethylated.

Improved colorimetric determination of aspirin and salicylic acid concentrations in human plasma.

An improvement in a previously described method for the determination of plasma salicylic acid and aspirin levels in humans is described. The procedure was simplified by employing only one plasma sample for both salicylates. More accurate estimation of salicylates, particularly aspirin, was achieved by using two different calibration curves. Salicylic acid was estimated by reaction with an aqueous solution of the Folin-Ciocalteu phenol reagent. Absorbance of the blue-colored complex, which formed on addition of sodium hydroxide, was measured at 670 nm. The influence of alkalinity in the formation of the colored complex is discussed. The average recovery of aspirin added to plasma was 94.61%; it was 214.72% by the previous method.

The effect of acetylsalicylic acid/salicylic acid mixtures on acetylcholinesterase activity in vitro.

An attempt was made to inhibit acetylcholinesterase activity in homogenates of rat brain and in 2% solutions of hemolyzed human or rat erythrocytes, with concentrations of acetylsalicylic acid/salicylic acid (ASA/SA) equivalent to those evident in human plasma 0--2 h after ingestion of 0.65 g of ASA. None of the 5 different ASA/SA mixtures used produced inhibition in any of the enzyme preparations while the reference compound, eserine, inhibited all. These results suggest that ingestion of ASA, at least in recommended doses, should not significantly influence acetylcholinesterase activity in vivo.

Influence of aspirin formulation and dose on concentration of total salicylate in rat kidney.

Rats received the equivalent of 100, 250, 500, or 700 mg/kg of 14C-aspirin orally as a suspension or as a solution of a buffered, effervescent, aspirin-containing product. Animals in each dose group were sacrificed at time intervals ranging from 0.5 to 24 hr after dosing. The 14C content of whole blood, plasma, and homogenized whole kidney (after perfusion) was determined. The concentration of total salicylate proved to be dose dependent and was lower in tissues from rats receiving the buffered, effervescent product, especially at the higher doses. The results suggest that salicylate-induced renal toxicity should be less likely to occur after administration of the buffered, effervescent formulation.

Does aspirin play a role in analgesic nephropathy?

Using a compound analgesic mixture, it was found that renal pathology could be produced in rats if the analgesic mixture was administered as a concentrated aqueous suspension, but that development of renal pathology was not favored by hot, dry environmental conditions. Determination of whole body total salicylate concentrations in rats and humans receiving various doses of aspirin revealed that twice daily doses of 24, 60 and 125 mg/kg aspirin in the rat were equivalent to human doses of 8, 20 and (approximately) 40 ordinary 325 mg aspirin tablets daily. These doses of aspirin were then employed in a subchronic study of the nephrotoxicity of aspirin in the rat using the experimental design which maximized the nephrotoxic effects of the compound analgesic mixture. Six groups of ten male and ten female rats received aspirin orally at doses of 24,60 or 125 mg/kg twice a day five days a week for 12 weeks. Two additional groups of ten male and ten female rats received only the vehicle, at a volume equivalent to that received by the high dose group, and served as controls. Four groups (one each, control, low, mid-, and high dose) were denied access to water for 16 hours daily overnight. No pathologic renal changes were observed in any of the rats. These findings are consistent with a growing body of evidence, from both animal and human studies, that aspirin alone does not produce analgesic nephropathy.

Influence of 1-methyl-3-keto-4-phenylquinuclidinium bromide on rat tissue monoamine levels in vivo.

The effects of 1-methyl-3-keto-4-phenylquinuclidinium bromide (MA540) on tissue monoamine levels in male rats have been compared to those of guanethidine. Neither compound influenced norepinephrine (NE) or 5-hydroxytryptamine (5-HT) levels in brain or epinephrine (E) levels in adrenal medulla. MA540 is about twice as potent as guanethidine as a heart NE depleting agent at both 8 and 24 h after drug administration. The durations of action of the compounds are similar. Unlike guanethidine, MA540 does not deplete NE in small intestine, which suggests that the drug may not elicit guanethidine-like intestinal side effects.

The biological disposition of 1-methyl-3-keto-4-phenylquinuclidinium bromide in the rat and dog.

The biological disposition of 1-methyl-3-keto-phenylquinuclidinium bromide (MA540) has been studied in the rat and dog. Gastrointestinal absorption of the drug was considerably different in the 2 species; about 15% and 75% of the dose in the rat and dog, respectively. Tissue distribution after i.v. administration was characterized by generally high tissue/plasma drug ratios in the rat and by low plasma (the only tissue examined) levels in the dog. Drug localization was apparent in the liver and adrenals, and the highest average (24-h) concentration was found in those tissues. The distribution profile and the chemical nature of MA540 suggest that the compound was distributed, at least initially, in extracellular water. MA540 was not extensively metabolized by either species. Excretion, although initially fairly rapid, slowed such that whole body half-lives were estimated to be 21 h and 47 h in the rat and dog, respectively.

Influence of a benzoquinolizinyl derivative on serum and hepatic alkaline phosphatase activity in the dog and rat.

Oral administration of 100 mg/kg of TR2379, N-(1,3,4,6,7-hexahydro-11bH-benzo[a]quinolizin-2-yl) propionanilide hydrochloride, for 20--29 days to 6 dogs resulted in significant elevations of alkaline phosphatase (AP) activity in serum and in liver microsomes. Results of biochemical and histochemical experiments revealed that the liver was the sole source of the increased AP activity but there was no evidence of liver damage. The subchronic (7-35 day) p.o. administration of TR2379 at 820 mg/kg to 20 rats did not produce elevation of AP activity in serum or liver. Relative liver weights (g/100 g body wt) of rats receiving TR2379 were significantly increased during the 2nd week and thereafter. The results of these studies suggest that high doses of TR2379 induce protein synthesis in dog and rat liver and induce AP activity in the dog but not in the rat. The elevation of AP in the dog is not considered to have toxicologic implications.