Evaluation of the excretion, and metabolism of the cardiotonic agent bemoradan in male rats and female beagle dogs.

The excretion and metabolism of (+/-) [6-(3,4-dihydro-3-oxo-1,4[2H]-benzoxazine-yl)-2,3,4,5-tetrahydro-5-methylpyridazin-3-one] (bemoradan; RWJ-22867) have been investigated in male Long-Evans rats and female beagle dogs. Radiolabeled [14C] bemoradan was administered to rats as a singkle 1 mg/kg suspension dose while the dogs received 0.1 mg/kg suspension dose. Plasma (0-24 h; rat and dog), urine (0-72 h; rat and dog) and fecal (0-72 h; rat and dog) samples were collected and analyzed. The terminal half-life of the total radioactivity for rats from plasma was estimate to be 4.3 +/- 0.1 h while for dogs it was 7.5 +/- 1.3 h. Recoveries of total radioactivity in urine and feces for rats were 49.1 +/- 2.4% and 51.1 +/- 4.9% of th dose, respectively. Recoveries of total radioactivity in urine and feces for dogs were 56.2 +/- 12.0% and 42.7 V 9.9% of the dose, respectively. Bemoradan and a total of nine metabolites were isolated and tentatively identified in rat and dog plasma, urine, and fecal extracts. Unchanged bemoradan accounted for approimately < 2% of the dose in rat urine and 20% in rat feces. Unchanged bemoradan accounted for approximately 5% of the dose in urine and 16% in feces in dog. Six proposed pathways were used to describe the metabolites found in rats and dogs: pyridazinyl oxidations, methyl hydroxylation, hydration, N-oxidation, dehydration and phase II conjugations.     

Pharmacokinetics and excretion of hydroxysafflor yellow A, a potent neuroprotective agent from safflower, in rats and dogs

Studies were conducted to characterize the pharmacokinetics and excretion of hydroxysafflor yellow A (HSYA) in rats and dogs after administration by intravenous injection or infusion. Plasma, urine, feces and bile concentrations of HSYA were measured using five validated mild HPLC methods. Linear pharmacokinetics of HSYA after the intravenous administrations were found at doses ranging from 3 to 24 mg/kg in rats and from 6 to 24 mg/kg in dogs. At a dose of 3 mg/kg, HSYA in urine, feces and bile was determined. For 48 h after dosing, the amount of urinary excretion accounted for 52.6 +/- 17.9 % (range: 31.1 - 78.7%, n = 6) of the dose, and the amount of fecal amount accounted for 8.4 +/- 5.3% (range 1.7 - 16.4%, n = 6) of the dose. Biliary excretion amount accounted for 1.4 +/- 1.0% (range 0.4-2.9%; n = 6) of the dose for 24 h after dosing. Percent plasma protein binding of HSYA ranged from 48.0 to 54.6% at 72 h. In summary, five mild HPLC methods for the determinations of HSYA in rat plasma, urine, feces, bile and dog plasma have been developed and successfully applied to preclinical pharmacokinetics and excretion of HSYA in rats and dogs. The results of excretion studies indicated that HSYA was rapidly excreted as unchanged drug in the urine. In view of previous pharmacological work, the concentration-dependent neuroprotective effect of HSYA in rats was defined.     

Pharmacokinetics of a Novel Antiarrhythmic Drug,Actisomide

The pharmacokinetics of a novel antiarrhythmic drug, actisomide, were examined in the rat, dog, monkey, and human. The terminal half-life of actisomide was similar (1.15–1.89 hr) across species, regardless of dose. The total plasma clearance was higher in the monkey (13.5–16.4 mL/min/kg) than in the dog (9.01–9.32 mL/min/kg), rat (8.6–9.8 mL/min/kg), or human (6.79 ± 1.07 mL/min/kg). Excretion of the parent drug was higher in urine than in feces in the dog and rat, whereas in the monkey and human, urinary and fecal excretions of actisomide were similar. In humans, atypical plasma concentration–time curves with double peak concentrations were observed following oral doses. Systemic availability of actisomide was higher in the dog than in the rat, monkey, and human. Further, the systemic availability appeared to increase with dose in the rat and monkey. The species-dependent systemic availability appeared to be due primarily to species-dependent absorption of actisomide, and not to species-dependent first-pass metabolism, biliary excretion, and/or renal elimination. The absorption of actisomide in the rat and its in vitro uptake in CaCo-2 cells were pH dependent. The higher systemic availability of actisomide observed in the dog may be due partly to the higher pH in the gastrointestinal (GI) tract of the dog. However, the pH differences in the GI tract of the different species alone did not appear to be enough to explain the difference in systemic availability of actisomide.     

Pharmacokinetics of nimodipine. I. Communication: absorption, concentration in plasma and excretion after single administration of [14C]nimodipine in rat, dog and monkey

Studies on absorption, plasma concentrations and excretion with (+/-)isopropyl-2-methoxyethyl-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl) -3,5-pyridinedicarboxylate (nimodipine, Bay e 9736, Nimotop) have been conducted in rat, dog and monkey using the carbon-14-labelled substance and a wide range of doses (0.05-10 mg/kg) administered via different routes (intravenous, oral, intraduodenal). Nimodipine was well absorbed in all species. Peak plasma concentrations of radioactivity were determined 28-40 min (male rat), 60 min (female rat), about 3 h (dog) and 7 h (monkey) after administration. Dependent on the observation period (24-216 h) terminal half-lives for the elimination of radioactivity from plasma ranging between 4.6 h (female rat) and 157 h (dog) were observed. Comparing the AUC, the concentration of unchanged [14C]nimodipine in plasma represented only a small (maximally 37% in dogs after i.v. dose) to negligible (about 1%, monkey after oral dosing) part of the total radioactivity. Excretion of radioactivity via feces and urine was rapid in all species after both oral and intravenous dosing. Fecal (biliary) excretion was the major excretory route in rat and dog. The monkeys excreted about 40 to 50% via the urine. Residues in the body never exceeded 1.5% of the dose. [14C]nimodipine and/or its radiolabelled metabolites were secreted in milk of orally dosed lactating rats. Binding of [14C]nimodipine to plasma proteins of rat and dog was about 97%.     

Pharmacokinetics and Pharmacodynamics of L-703,014, a Potent Fibrinogen Receptor Antagonist,After Intravenous and Oral Administration in the Dog

The pharmacokinetics and pharmacodynamics of L-703,014, a fibrinogen receptor antagonist, have been examined in the dog. An analytical method which utilizes methanol precipitation of dog plasma proteins followed by HPLC with an automated column switching technique using the chemical analogue L-704,326 as internal standard was developed for the determination of L-703,014 in dog plasma. The compound was not metabolized in the dog and was eliminated in the kidneys and into bile. Of the administered dose, 68.9 ± 1.3% (i.v.) and 80.5 ± 11.9% (p.o.) were recovered in the feces; 20.3 ± 3% (i.v.) and 2.2 ± 0.2% (p.o.) were recovered in the urine by 72 hr. L-703,014 was 23 ± 3.4% bound in dog plasma protein and the mean ratio of plasma/whole blood was 1.22 ± 0.05. The mean terminal half-life was 118 ± 36 min, the mean steady-state volume of distribution was 0.61 ± 0.22 L/kg, and the mean plasma clearance was 8 ± 2 mL/min/kg. Ex vivo platelet aggregation measurements were made by inducing platelet aggregation with 10 µg/ mL collagen in the presence of 1 µM epinephrine as an agonist. The mean C ₅₀ was 44.4 ± 6.0 ng/mL, and the mean Hill coefficient was 1.5 ± 0.3. The mean bioavailability was 4.9 ± 1.4% in dogs administered 2.0 mg/kg (p.o.).     

Evaluation of the absorption, excretion, and metabolism of the antihypertensive agent RWJ-26899 in male and female CR Wistar rats and Beagle dogs.

The absorption, excretion and metabolism of N-(2, 6-dichlorophenyl)-beta-[[(1-methylcyclohexyl)methoxylmethyl]-N-(phenylmethyl)-1-pyrrolidineethanamine (RWJ-26899; McN-6497) has been investigated in male and female CR Wistar rats and beagle dogs. Radiolabeled [14C] RWJ-26899 was administered to rats as a single 24 mg/kg suspension dose while the dogs received 15 mg/kg capsules. Plasma (0-36 h; rat and 0-48 h; dog), urine (0-192 h; rat and dog) and fecal (0-192 h; rat and dog) samples were collected and analyzed. There were no significant gender differences observed in the data. The terminal half-life of the total radioactivity for rats from plasma was estimated to be 7.7 +/- 0.6 h while for dogs it was 22.9 +/- 4.4 h. Recoveries of total radioactivity in urine and feces for rats were 8.7 +/- 2.9% and 88.3 +/- 10.4% of the dose, respectively. Recoveries of total radioactivity in urine and feces for dogs were 4.1 +/- 1.4% and 90.0 +/- 4.7% of the dose, respectively. RWJ-26899 and a total of nine metabolites were isolated and tentatively identified in rat urine, and fecal extracts. Unchanged RWJ-26899 accounted for approximately 1% of the dose in rat urine and 8% in rat feces. RWJ-26899 and a total of four metabolites were isolated and identified in dog urine, and fecal extracts. Unchanged RWJ-26899 accounted for approximately 1% of the dose in urine and 63% in feces in dog. Five proposed pathways were used to describe the metabolites found in rats: N-oxidation, oxidative N-debenzylation, pyrrolidinyl ring hydroxylation, phenyl hydroxylation and methyl or cyclohexyl hydroxylation. Two biotransformation pathways in dogs are proposed: N-oxidation and methyl or cyclohexyl ring hydroxylation.     

4,4′-Dichlorobiphenyl: Distribution,metabolism, and excretion in the dog and the monkey

The tissue distribution, metabolism, and excretion of 4,4′-dichlorobiphenyl (4,4′-DCB) were investigated in beagle dogs and cynomolgus monkeys (Macaca fascicularis). Following a single iv dose of [¹⁴C]4,4′-DCB (0.6 mg/kg) excreta, blood, and tissues were collected at time intervals ranging from 15 min to 28 days for determination of levels of parent compound and its metabolites. Elimination of the parent PCB in the blood of both species was biphasic with a terminal-phase elimination rate constant of 0.018 hr^?1 for the dog and 0.002 hr^?1 for the monkey. By 24 hr the dog excreted 50% of the dose in the feces (43%) and the urine (7%). The percentage dose remaining was found largely as parent compound in the fat with some in muscle and skin. By 5 days 90% of the dose was excreted. In contrast, during the first 24 hr the monkey excreted less than 15% of the dose with less than 1% in the feces. The percentage dose remaining in the body was localized as parent compound in fat (33%) with lesser amounts in skin and muscle. By 28 days 59% of the dose was excreted, primarily in the urine. In anesthetized dogs 33% of the dose was excreted into the bile within 2 hr, while the monkey excreted only 0.4% of the dose by that route. The data present a clear species variation between the dog and the monkey in both the rate and route of excretion of 4,4′-DCB.     

Pharmacokinetics, metabolism, and disposition of 6-chloro-2,3,4,5-tetrahydro-3-methyl-1H-3-benzazepine (SK&F 86466) in rats and dogs

The pharmacokinetics and metabolism of 6-chloro-2,3,4,5-tetrahydro-3-methyl-1H-3-benzazepine (SK&F 86466) have been studied in rats and dogs. Using radiolabeled SK&F 86466, it was shown that the compound was completely absorbed from the gastrointestinal tract following oral administration. Most of the administered radioactivity (approximately 80%) was excreted in urine with the remainder excreted in feces via the bile. Very little of the parent compound was excreted unchanged in the urine. The major urinary metabolite, accounting for about 55% of the dose in rat and 35% in dog, was the N-oxide. N-Demethylation also occurs in both species, and in the rat approximately 20% of the dose is metabolized by this route. The plasma concentration vs. time curves following iv administration were analyzed using a two-compartment open model. The distribution phase half-life was 0.24 hr in the rat and 0.37 hr in the dog. In both species the terminal half-life was approximately 2 hr. The volume of distribution at steady state in the rat was 12.1 liters/kg and in the dog was 8.2 liters/kg. About 55% of the drug in plasma was bound to protein in both species so that the volume of distribution of the free drug was 27 liters/kg in the rat and 19 liters/kg in the dog. The clearance of SK&F 86466 from blood was very high in both the dog (56 ml/min/kg) and the rat (191 ml/min/kg). Since less than 1% of the compound was excreted unchanged in urine, the clearance was almost entirely metabolic.(ABSTRACT TRUNCATED AT 250 WORDS)     

2,3,6,2′,3′,6′-Hexachlorobiphenyl: Distribution,metabolism, and excretion in the dog and the monkey

The tissue distribution, metabolism, and excretion of 2,3,6,2′,3′,6′-hexachlorobiphenyl (236-HCB) were investigated in beagle dogs and cynomolgus monkeys (Macaca fascicularis). Following a single iv dose of [¹⁴C]236-HCB (0.6 mg/kg) excreta, blood, and tissues were collected at time intervals ranging from 15 min to 15 days for determination of levels of parent compound and its metabolites. Elimination of the parent PCB in the blood of both species was biphasic with a terminal-phase elimination rate constant of 0.23 day^?1 for the dog and 0.15 day^?1 for the monkey. By 24 hr the dog excreted 52% of the dose; 41% in the feces; 11% in the urine. The percentage dose remaining was found largely in liver, muscle, fat, and skin. By 3 days 70% of the dose was excreted. During the first 24 hr the monkey excreted 19% of the dose with about equal amounts appearing in urine and feces. The percentage dose remaining in the body was localized as parent compound in fat (15%) with lesser amounts in skin, muscle, and liver. By 15 days 61% of the dose was excreted, primarily in the feces. In anesthetized dogs 26% of the dose was excreted into the bile within 2 hr, while anesthetized monkeys excreted only 2.4% of the dose by that route. The data present a clear species variation between the dog and the monkey in the rate of metabolism of 236-HCB and its subsequent excretion via the bile.     

Biological properties of the antagonist SRI 63-441 in the PAF and endotoxin models of hypotension in the rat and dog

Intravenous administration of platelet-activating factor (PAF) produces dose-dependent hypotension in several species. We have evaluated a recently developed PAF antagonist, SRI 63-441, for its ability to inhibit the hypotensive effect of PAF in the rat and dog. In the rat, 100 ng/kg PAF produced a 38.6 +/- 5.1% decrease in carotid mean arterial pressure (MAP), followed by a 3.2 +/- 0.7 min recovery period for MAP to return to baseline values. SRI 63-441 reduced the hypotension response in the rat, where the ED50 values for inhibition of MAP were 0.16 mg/kg i.v. and 0.19 mg/kg i.v. for the recovery period. Dogs challenged with 1.5 micrograms/kg PAF i.v. demonstrated a 52 +/- 8% decrease in MAP that persisted for at least 15 min. The ED50 for inhibition of MAP by SRI 63-441 was 0.20 mg/kg i.v. Following injection of tritium-labeled SRI 63-441, 56.8 +/- 2.4% of the dose was recovered in the urine and 43.2 +/- 8.9% in the feces in the rats while in dogs 38.7 +/- 5.6% and 60.9 +/- 23.5% of the dose was excreted in the urine and feces, respectively. In the rat model of endotoxin-induced hypotension, SRI 63-441 given 1 min after a 5 mg/kg endotoxin challenge (which produced a 52 +/- 7% decrease in MAP), reversed the systemic effects, with an ED50 of 0.18 mg/kg i.v. The ED50 for reversal 6 min after endotoxin injection was 0.01 mg/kg. These results of inhibition and reversal by SRI 63-441 strongly implicate PAF as a pivotal mediator of hypotension and shock.     

The metabolism of 14C-cibenzoline in dogs and rats

The disposition of the new antiarrhythmic agent cibenzoline (CBZ) (racemic 4,5-dihydro-2-(2,2-diphenylcyclopropyl)-1H-imidazole) in three male dogs was investigated after oral administration of 13.8 mg/kg of 14C-CBZ base. Within 6 days, 60.5 +/- 6.0% of the dose was excreted in urine and 19.2 +/- 4.6% in feces. In 0-24-hr urine, unchanged drug was excreted (41.6% of the dose) as well as the unconjugated 4,5-dehydro metabolite (DHCBZ, 3.7%), conjugated p-hydroxybenzophenone (0.8%, only in one dog), and a phenolic metabolite, p-hydroxycibenzoline (HCBZ) in a rearranged form (RHCBZ) at 5.2% of the dose (free plus conjugated). Studies with synthetic HCBZ indicated that unrearranged HCBZ was excreted and that rearrangement occurred during purification. CBZ from dog urine displayed slight optical activity, based on ORD/CD data, corresponding to an optical purity of 15% of the S-(-)-CBZ, indicating a limited extent of stereoselective metabolism of CBZ in dogs. After an oral 50-mg/kg dose of 14C-CBZ succinate, male rats excreted in 3 days 27.0 +/- 2.8% in urine and 41.5 +/- 2.6% of the dose in feces, and in a repeated experiment 32.1 +/- 1.9% in urine and 54.5 +/- 0.7% in feces. CBZ (7.6%) and DHCBZ (0.2%) were determined in 0-24-hr urine, and CBZ (4.2%) and RHCBZ (4.2% of the dose) were determined in 0-24-hr feces. RHCBZ (3.1%), m-methoxy p-hydroxycibenzoline (8.3%), and p-hydroxybenzophenone (5.3% of the dose) were identified as glucuronide/sulfate conjugates in bile from rats. Evidence that p-hydroxybenzophenone arose from an unstable unidentified metabolite is discussed.     

2,4,5,2',4',5'-Hexachlorobiphenyl: distribution, metabolism, and excretion in the dog and the monkey

The tissue distribution, metabolism, and excretion of 2,4,5,2′,4′,5′-hexachlorobiphenyl (2,4,5-HCB) were investigated in beagle dogs and cynomolgus monkeys (Macacca fascicularis). Following a single iv dose of [¹⁴C]2,4,5-HCB (0.6 mg/kg), excreta, blood, and tissues were collected at time intervals ranging from 30 min to 15 days for dogs and 2 hr to 90 days for monkeys. The concentration of 2,4,5-HCB and its metabolites was determined in all samples. Elimination of the parent PCB from the blood of both species was biphasic with a terminal phase elimination rate constant of 0.045 day^?1 for the dog and 0.015 day^?1 for the monkey. By 15 days the dog had excreted 66% of the dose, 63% in the feces, and 3% in the urine. The percentage dose remaining was found largely as parent compound in the adipose tissue (16%), skin (6%), and muscle (2%). By 90 days, the monkey had excreted only 18% of the dose (17% in feces, 1% in urine). Again, the major storage depots for nonexcreted dose were adipose tissue 945%) and skin (5%). In anesthetized dogs, 0.8% of the dose appeared in the bile within 2 hr, while only 0.2% of the dose appeared in the bile of anesthetized monkeys in 2 hr. The monkey excreted a greater percentage of dose as parent compound into the bile than the dog. The data provide evidence that the pharmacokinetic behavior of 2,4,5-HCB in the monkey is similar to that observed in other species. However, the dog is unique from other species in that it can readily eliminate 2,4,5-HCB.     

Pharmacokinetics of falipamil after intravenous administration to humans

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.     

Pharmacokinetics and pharmacodynamics of intravenous cibenzoline in normal volunteers

The pharmacokinetics of intravenous (IV) cibenzoline were studied in six healthy male volunteers ranging in age from 51 to 78 years. The subjects received intravenous (IV) cibenzoline 100 mg over 20 minutes, and plasma and urine specimens were collected for 48 hours. Cibenzoline plasma concentrations at the end of the infusion ranged from 730 to 1,420 ng/mL and exhibited triexponential decline thereafter. The following mean model independent pharmacokinetic parameters were calculated from the plasma and urine concentration data: terminal half-life, 9.8 hours (range, 8.5-11.9); plasma clearance, 523 mL/min (range, 387-687); volume of distribution, 445 L (range, 328-506); and renal clearance, 289 mL/min (range, 202-334). Approximately 31% to 59% of the dose was recovered unchanged in the urine in 48 hours. A triexponential pharmacokinetic equation with zero order input was used to curve fit the plasma and urine data, and the model-dependent parameters agreed well with the model-independent estimates. A hysteresis loop was observed in the relationship between cibenzoline plasma concentration and QRS prolongation, indicating an initial lag between plasma concentration and effect after IV administration. Based on these results, the following preliminary dosing regimen was proposed to rapidly achieve and maintain therapeutic plasma concentrations equal to or slightly greater than 200-400 ng/mL: 0.25 mg/kg/min IV bolus over one minute followed by 1-1.5 mg/kg/hr for one hour and 0.2-0.4 mg/kg/hr for long-term infusion.     

染料木黄酮在Beagle犬体内的药代动力学染料木黄酮在Beagle犬体内的药代动力学

目的研究染料木黄酮(genistein)在Beagle犬体内的药代动力学。方法染料木黄酮ig后用反相高效液相色谱法测定犬血浆、尿及粪便中原型药物浓度,血浆药物浓度-时间数据用3P97药代动力学软件分析。结果Genistein在Beagle犬体内的代谢符合一室模型,ig后0.29 h达药峰浓度,t1/2 Ke为0.52 h。给药后24 h内有10.79%的原型药物由尿排出,21.55%的原型药物由粪便排出。60 h内有13.00%的原型药物由尿排出,有52.46%的原型药物由粪便排出。结论Beagle犬ig染料木黄酮后吸收迅速,血浆中药物的消除速度快,药物主要以原型经尿和粪便排出体外。     

Pharmacokinetics of morphine and its surrogates. VII: High-performance liquid chromatographic analyses and pharmacokinetics of methadone and its derived metabolites in dogs

Reversed-phase HPLC assays with on-column UV detection and post-column fluorescent detection of ion pair-extracted material were developed and used for the quantitative assay of methadone, its presumed metabolites, and acid- and alkali-hydrolyzable conjugates of these metabolites in biological fluids with assay sensitivities of 10-20 ng/mL. Plasma, urine, and bile were monitored in dogs after intravenous bolus administration of 0.8, 1.0, 2.0, and 2.2 mg/kg methadone hydrochloride. Plasma-time data showed two sequential half-lives of 8.3 +/- 3.4 (SEM) and 128 +/- 37 min, with apparent dose-independent pharmacokinetics in the studied dose range. Total body clearances were 899 +/- 103 (SEM) mL/min. Renal clearances (6-82 mL/min) of methadone were highly variable within and among studies but showed no significant variation with urinary pH or flow rate. The percentages of the dose excreted in the urine as methadone and (+)-2-ethyl-1,5-dimethyl-3,3-diphenylpyrroline (2) were 3.6 +/- 0.5% (SEM) and 4.1 +/- 0.4% (SEM), respectively, but there were no significant concentrations of 2 in plasma. The presumed metabolites 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline (3), 1,5-dimethyl-3,3-diphenyl-2-pyrrolidone (4), (-)-alpha-N-normethadol (7), 4-dimethylamino-2,2-diphenylvaleric acid (8), p-hydroxymethadone (9), and (-)-alpha-methadol (10) were not observed in the plasma of dogs given methadone. Quantities of presumed metabolites 3, 4, 7, 8, 9, and 10 were negligible in urine (less than 0.03% of dose). No acid-hydrolyzable conjugates, or generators on acidification, of 3, 4, 7, 8, or 10 were detectable in urine. No alkali-hydrolyzable conjugates, or generators on alkalinization, of 3, 4, 8, or 10 were detectable in urine. There was no significant biliary secretion of unchanged methadone; 2 in bile amounted to only 2% of the dose. In bile and urine, 50% and 17-27%, respectively, of the radiolabeled dose was not extractable into hexane. In a non-bile-cannulated dog, 35% of the total radiolabeled intravenous dose was present in the feces. As much as 88% of an intravenous radiolabeled dose could be accounted for, even though only small amount of methadone was disposed through the metabolic routes claimed in the literature. The intravenous administration of 2 resulted in two sequential half-lives of 3 and 270 min and no apparent pharmacokinetic dose dependency. Amounts of 2 excreted unchanged in urine and bile were 23% and 5-16% of the dose, respectively. Renal and total body clearances were 170 and 1150 mL/min.(ABSTRACT TRUNCATED AT 400 WORDS)     

Pharmacokinetics and excretion of the novel anti-tuberculosis compound 1,2:5,6-di-O-isopropylidene-3-O-(phenyl cyclopropyl methanonyl)-alpha-D-glucofuranose (S-001-14) after oral doses in rats. Development of a sensitive and reproducible high performance liquid chromatography-UV method for the determination of the test compound in rat serum

A sensitive and reproducible high performance liquid chromatography (HPLC)-UV method for the determination of the novel anti-tuberculosis compound 1,2:5,6-di-O-isopropylidene-3-O-(phenyl cyclopropyl methanonyl)-alpha-D-glucofuranose (S-001-14) has been developed and validated in rat serum, urine and feces. Following extraction with hexane at alkaline pH, samples were separated on a reverse phase C18 column and quantified using UV detection at 267 nm. The mobile phase was 70% acetonitrile in ammonium acetate buffer (10 mmol/L, pH 6.0) with a flow rate of 1.0 ml/min. The method was used to determine the pharmacokinetics and excretion of S-001-14 after oral doses in rats. Linearity was satisfactory over the concentration range of 5-500 ng/ml (r2, > 0.99). Recoveries were > 90% and were consistent throughout the calibration range. The precision and accuracy were acceptable as indicated by relative standard deviation ranging from 2.72 to 9.54%, bias values ranging from 1.62 to 12.05%. Moreover, S-001-14 was stable in rat serum after being subjected to three freeze-thaw cycles and for 30 days on storage at - 60 degrees C. The method was used to determine the serum concentration-time profiles for S-001-14 after oral doses of 4, 100 and 200 mg/kg in rats. A linear pharmacokinetics was found in rats at 100 and 200 mg/kg doses with a long elimination half-life (approximately 24 h), wide distribution and bioavailability of approximately 13%. The excretion study after the 100 mg/kg oral dose revealed that S-001-14 was excreted in urine (0.002 +/- 0.001%) and feces (15.6 +/- 3.5%).     

63Ni-NiCl2在大鼠体内的药代动力学及其组织残留

镍是动物体必需的微量元素,参与核酸和蛋白质的代谢、激素的调节过程,具有刺激生血、促进红细胞再生的功能[1],与激素、蛋白质和脂类的代谢也密切相关.国内相关研究较少,尤其使用同位素标记法研究更少.     

Pharmacokinetics, skin absorption, stability, blood partition, and protein binding of AS 2-006A, a new wound healing agent

After intravenous administration of AS 2-006A, 20, 50, and 90 mg/kg, to rats, the pharmacokinetic parameters, terminal half-life (69.8-86. 6 min), mean residence time (56.2-75.2 min), apparent volume of distribution at steady state (809-1040 mL/kg), and total body clearance (11.4-11.9 mL/min/kg), were dose-independent. After topical application of 0.5 or 1% AS 2-006A ointment, 300 mg, to abraded rat skin, the absorbed amounts were dose (0.5 and 1%) and time (30, 60, 120, 240, 360 and 480 min)-independent; the value was approximately 20%. The tissue-to-plasma ratios of AS 2-006A were greater than unity in all rat tissues studied, except in the muscle and large intestine. AS 2-006A was stable for up to 24 h incubation in rat plasma, and human plasma and urine; however, it seemed not to be stable in rat urine; the disappearance rate constant was 0.0218/h. AS 2-006A reached equilibrium fast between plasma and blood cells, and the equilibrium plasma/blood cells partition ratios were independent of the initial rabbit blood concentrations of AS 2-006A, 10, 20, and 50 microg/mL; the mean values were in the range of 2.38-2.75 for three rabbit blood. The protein binding of AS 2-006A to rat plasma was high, as the drug was under detection limit in the filtrate at the plasma concentrations of the drug, ranging from 7.21 to 228 microg/mL.     

The metabolic disposition of (S)-2-(3-tert-butylamino-2-hydroxypropoxy)-3-cyanopyridine in rats, dogs, and humans

Studies of the metabolic disposition of (S)-2-(3-tert-butylamino-2-hydroxypropoxy)-3-[14C]cyanopyridine (I) have been performed in humans, dogs, and spontaneously hypertensive rats. After an iv injection of I (5 mg/kg), a substantial fraction of the radioactivity was excreted in the feces of rats (32%) and dogs (31%). After oral administration of I (5 mg/kg) the urinary recoveries of radioactivity for rat and dog were 19% and 53%, respectively, and represented a minimum value for absorption because of biliary excretion of radioactivity. In man, bililary excretion of I appeared to be of minor significance because four male subjects, after receiving 6 mg of I p.o., excreted 76% and 9% of the dose of radioactivity in the urine and feces, respectively. Unchanged I represented 58% of the radioactivity excreted in human urine. The half-life for renal elimination of I was determined to be 4.0 +/- 0.9 /hr. In contrast, unchanged I represented 7% and 1% of excreted radioactivity in rat and dog urine, respectively. A metabolite of I common to man, dog, and rat was identified as 5-hydroxy-I, which represented approximately 5% of the excreted radioactivity in all species. Minor metabolites of I in which the pyridine nucleus had undergone additional hydroxylation were present in dog urine along with an oxyacetic acid metabolite, also bearing a hydroxylated pyridine nucleus.