Absorption and excretion of 3H-raubasine in human subjects and dogs

The pharmacokinetic behavior of (3,5,6-3H)-raubasine (RAU) was investigated in human subjects after oral administration and in dogs after both intravenous and oral administration. By the oral route RAU peak plasma levels appeared in human subjects after 1 h and in dogs after 2 h. Three-day cumulative urinary excretion was 22% by i.v. route and 13% by oral route in dogs, being 29% in human subjects after oral administration. Three-day cumulative faecal excretion in dogs was 51% by i.v. route and 57% by oral route whilst it was 24% in humans. From a comparison between the urinary excretion values observed after i.v. and oral administration, a RAU intestinal absorption of 59% may be obtained.     

Absorption,distribution, metabolism and excretion of gemigliptin,a novel dipeptidyl peptidase IV inhibitor,in rats

Abstract

1.?The absorption, distribution, metabolism and excretion of a novel dipeptidyl peptidase IV inhibitor, gemigliptin, were examined following single oral administration of ¹⁴C-labeled gemigliptin to rats.

2.?The ¹⁴C-labeled gemigliptin was rapidly absorbed after oral administration, and its bioavailability was 95.2% (by total radioactivity). Distribution to specific tissues other than the digestive organs was not observed. Within 7 days after oral administration, 43.6% of the administered dose was excreted via urine and 41.2% was excreted via feces. Biliary excretion of the radioactivity was about 17.7% for the first 24?h. After oral administration of gemigliptin to rats, the in vivo metabolism of gemigliptin was investigated with bile, urine, feces, plasma and liver samples.

3.?The major metabolic pathway was hydroxylation, and the major circulating metabolites were a dehydrated metabolite (LC15-0516) and hydroxylated metabolites (LC15-0635 and LC15-0636).     

Intestinal absorption, intestinal distribution, and excretion of (14C) labelled hyoscine N-butylbromide (butylscopolamine) in the rat

Butylscopolamine was labelled with ¹⁴C and its gastrointestinal absorption, biliary and urinary excretion, enterohepatic circulation and gastrointestinal distribution were examined in anaesthetized rats. Biliary excretion was the main elimination route of intra-portally administered [¹⁴C]butylscopolamine, with 42% of the dose recovered in the bile during 12 h. About 6% of the radioactivity administered orally as [¹⁴C]butylscopolamine was excreted in the bile and 1.2 % in the urine during 24 h, which indicates poor gastrointestinal absorption of butylscopolamine in the rat. When collected radioactive bile was readministered intrajejunally, only about 7% of the radioactivity was recovered in bile and urine during 12 h, which suggests that only a small fraction of butylscopolamine and its metabolites engage in an enterohepatic circulation. After oral administration of [¹⁴C]butylscopolamine, radioactivity was found to accumulate in the wall of the distal small intestine, and about 20% of the dose was found in this tissue 24 h after drug administration. As a result, local anti-acetylcholine effects of butylscopolamine might be expected.     

Absorption,distribution and excretion of nilvadipine,a new dihydropyridine calcium antagonist,in rats and dogs

1. The absorption, distribution and excretion of nilvadipine have been studied in male rats and dogs after an i.v. (1 mg/kg for rats, 0.1 mg/kg for dogs) and oral dose (10 mg/kg for rats, 1 mg/kg for dogs) of ¹⁴C-nilvadipine.

2. Nilvadipine was rapidly and almost completely absorbed after oral dosing in both species; oral bioavailability was 4.3% in rats and 37.0% in dogs due to extensive first-pass metabolism. The ratios of unchanged drug to radioactivity in plasma after oral dosing were 0.4–3.5% in rats and 10.4–22.6% in dogs. The half-lives of radioactivity in plasma after i.v. and oral dosing were similar, i.e. 8–10h in rats, estimated from 2 to 24 h after dosing and 1.5 d in dogs, estimated from 1 to 3 d. In contrast, plasma concentrations of unchanged drug after i.v. dosing declined biexponentially with terminal phase half-lives of 1.2 h in rats and 4.4 h in dogs.

3. After i.v. dosing to rats, radioactivity was rapidly distributed to various tissues, and maintained in high concentrations in the liver and kidneys. In contrast, after oral dosing to rats, radioactivity was distributed mainly in liver and kidneys.

4. With both routes of dosing, urinary excretion of radioactivity was 21–24% dose in rats and 56–61% in dogs, mainly in 24 h. After i.v. dosing to bile duct-cannulated rats, 75% of the radioactive dose was excreted in the bile. Only traces of unchanged drug were excreted in urine and bile.     

Ergot alkaloids: Hepatic distribution and estimation of absorption by measurement of total radioactivity in bile and urine

The extent of availability is a measure of the amount of unchanged drug which reaches the systemic circulation following an oral dose. However, absorption as discussed in this communication has the generally accepted meaning of a measure of the disappearance of drug from the gastrointestinal tract and the entrance into the systemic circulation, either as unchanged drug or as metabolite. For many substances, e.g., dihydroergocristine, dihydroergotamine, and ergotamine, excretion in the bile is the most important route of elimination. Determination of the enteral absorption of these compounds from the urinary ratio, i.e., from the ratio of urinary excretion after oral and after intravenous administration, presents a problem, since the quantities found in the wine are small and the hepatic distribution ratio, i.e., the biliary to urinary excretion ratio, can vary depending on the route of administration. We have shown for dihydroergocristine-9,10-³H in the rat that the hepatic distribution ratio calculated from the data for intravenous and oral administration must remain constant if absorption is to be determined from the ratio of oral to intravenous radioactivity excreted either in the bile alone or in the urine alone. If this requirement is not met, but one can account for all of the radioactivity following an oral dose, it is necessary to measure the sum of biliary and urinary excretion of the labeled compounds after oral administration only. This method does not depend on the ratio of the amounts of radioactivity excreted by various routes or on the ratio of unchanged to metabolized compound. By this method, it is possible to detect differences in absorption and in the hepatic distribution ratio. In experiments on bile fistula monkeys, it was shown that the hepatic distribution ratio is, in fact, constant, despite the fact that the enteral absorption of ergotamine is 3 times that of dihydroergotamine.     

Pharmacokinetic properties of the antimuscarinic drug [3H]-hexahydro-sila-difenidol in the rat

Summary The pharmacokinetics of tritiated hexahydrosila-difenidol ([³H]-HHSiD) were examined in rats. Furthermore, the distribution of radioactivity was studied by means of whole body autoradiography.After i. v. administration of 2.9 mg/kg HHSiD plus [³H]-HHSiD to anaesthetized rats bearing a catheter implanted in the ductus choledochus and receiving a mannitol infusion, HHSiD was rapidly distributed and metabolized. Only 5% of the radioactivity was recovered in blood after 23 s and 0.4% after 2.5 h. 64% of the plasma radioactivity could be extracted with hexane from the samples taken 23 s after administration. 52% of the radioactivity was eliminated within 2.5 h, 13% by urinary and 39% by biliary excretion.Following oral administration of 8.6 mg/kg HHSiD plus [³H]-HHSiD there was an absorption of approximately one fourth of the administered radioactivity within 4 h. By means of whole body autoradiography (i. v. injection) as well as by tissue distribution measurement the highest levels of radioactivity were found in bile, urine, lung, kidney, adrenals, liver and pancreas. Thus, after i. v. administration to rats HHSiD is rather quickly distributed, metabolized and excreted. This explains its low antimuscarinic potency in vivo.Send offprint requests to E. Mutschler at the above address     

Absorption, distribution, metabolism and excretion of glucosamine sulfate. A review

This article reviews the literature related to the absorption, distribution, metabolism and excretion (ADME) of glucosamine (Gl) in man and in animals after administration of crystalline glucosamine sulfate (CGS). Intravenous administration of CGS In man, after single bolus intravenous (i.v.) injection of 1005 mg CGS (628 mg Gl), the parent Gl disappears from plasma with an apparent half life of 1.11 h. Investigations with uniformly 14C labeled Gl (14C-Gl) administered with 502 mg CGS indicate that the disappearance of Gl is due to an incorporation into the plasma globulins that occurs with a lag time of 0.45 h and a rate of 0.26 h-1. The radioactivity reaches a peak after 10 h and is eliminated with a t1/2 of 95 h. After single i.v. doses of 502 mg CGS traced with 14C-Gl, the urinary excretion in 120 h accounted for 29% of the administered dose. Consistent results are obtained in rat and dogs, in which radioactivity rapidly appears in liver, kidneys and other tissues, including the articular cartilage. In man, after i.v. bolus injection of 1005 mg CGS, the urinary excretion in 24 h of Gl determined with ion exchange chromatography was 38% of the administered dose, mostly in the first 8 h after administration. Similar results were obtained tracing CGS with 14C-Gl. Consistent results of urinary excretion were obtained in rats and dogs tracing CGS with 14C-Gl. The excretion of radioactivity in feces was small. The elimination of radioactivity with the expired air as 14CO2 measured in rats amounted to 49% of the administered dose in the 144 h following the administration, 16% of which occurred in the first 6 h. Intramuscular administration of CGS In man, a single intramuscular injection of 502 mg CGS traced with 14C-Gl, gave results similar to those after i.v. administration. Oral administration of CGS In man, after a single dose of 7.5 g CGS, Gl in plasma was below the limit of quantitation (3 micrograms/ml) of the ion exchange chromatography method. After a single dose of 314 mg CGS traced with 14C-Gl, radioactivity appeared incorporated in plasma globulins with a lag time of 1.5 h and increasing with a rate of 0.24 h-1. The peak was reached at the 9th h after administration. The radioactivity then was eliminated with a t1/2 of 58 h. The absolute oral bioavailability evaluated on the AUCs of the globulin-incorporated radioactivity was 44%. The fecal excretion in 120 h was 11.3% of the administered dose showing that at least 88.7% of the administered dose was absorbed through the gastrointestinal tract. The difference of 45% is probably due to a hepatic first-pass effect. Investigated in the rat with doses from 126 to 3768 mg CGS traced with 14C-Gl, a linear relationship was found with the AUCs as well as between doses and the Cmax of radioactivity in total and in deproteinized plasma. The urinary elimination in man of the parent Gl in 24 h determined with ion exchange chromatography after a single dose of 7.5 g of CGS was 1.19% of the administered dose, occurring mostly in the first 8 h after administration. After administration of 1884 mg repeated for 7 days the daily urinary excretion of Gl increased from 1.60% of the daily dose during the first 24 h to 2.22% of the daily dose in the last 24 h. The steady state was reached after the second day. The urinary excretion at steady state during repeated administration allowed to conclude that daily 1884 CGS administered either t.i.d. in sugar coated tablets or once a day in oral solution were bioequivalent. The elimination of radioactivity with the expired as 14CO2 measured in rats was 82% of the administered dose in the 144 h following the administration, 61% of which occur in the first 6 h. Interaction of Gl with the ADME of glucose The ADME of glucose was investigated in the rat administering i.v. or orally 14C uniformly labeled glucose. The kinetic in plasma and the tissue distribution of glucose differed totally from those of Gl, pointing out that exogenous glucose provides the energy for biochemical processes, whereas exogenous Gl acts mainly as substrate for the biosynthesis of mucopolysaccharides and of biopolymers of the articulations and bones. There was no evidence of interaction by Gl orally administered with the ADME of glucose.     

Absorption,excretion and metabolism of tiquizium bromide in dogs,and relationship between pharmacological effect and plasma levels of unchanged drug

1. The disposition of ¹⁴C-tiquizium bromide was investigated in dogs after oral administration and i.v. administration.

2. After oral administration, max. blood concn. of radioactivity were obtained from one to three hours after dosing. The half-lives of the terminal phase were 7.1?h (i.v.) and 9.4-12.0?h (p.o.). The relative bioavailability was 26%. The urinary excretion in three days was 24% (i.v.) and 5-9% (p.o.).

3. The most important mechanism of biotransformation was hydroxylation in the 5-position of the thiophene ring, and glucuronides of the isomeric hydroxylated products of tiquizium bromide were found in urine.

4. The time-course of the inhibitory effect of tiquizium bromide on stomach contraction correlated well with the plasma levels of unchanged drug after intraduodenal administration.     

Absorption,distribution and excretion of the new thienopyridine agent prasugrel in rats

Prasugrel is converted to the pharmacologically active metabolite after oral dosing in vivo. In this study, ¹⁴C-prasugrel or prasugrel was administered to rats at a dose of 5?mg?kg^–1. After oral and intravenous dosing, the values of AUC_0–∞ of total radioactivity were 36.2 and 47.1?µg?eq.?h?ml^–1, respectively. Oral dosing of unlabeled prasugrel showed the second highest AUC_0–8 of the active metabolite of six metabolites analyzed. Quantitative whole body autoradiography showed high radioactivity concentrations in tissues for absorption and excretion at 1?h after oral administration, and were low at 72?h. The excretion of radioactivity in the urine and feces were 20.2% and 78.7%, respectively, after oral dosing. Most radioactivity after oral dosing was excreted in bile (90.1%), which was reabsorbed moderately (62.4%). The results showed that orally administered prasugrel was rapidly and fully absorbed and efficiently converted to the active metabolite with no marked distribution in a particular tissue.     

Disposition of β-methyldigoxin in man

Summary The time course of radioactivity in plasma and the excretion in urine and faeces over 7 days were determined in 12 healthy subjects after single oral and intravenous doses of a solution of³H--methyldigoxin. 62.2±2.1 and 29.0±5.2 per cent of the dose were excreted in urine and faeces, respectively, within 7 days of intravenous administration, compared with 55.2±2.8 and 28.6±5.7 per cent after oral administration. This indicates almost complete absorption of the glycoside when given in solution. 12 hours after its administration a pseudo-distribution equilibrium was reached and the average half life of tritiated compounds was 1.3 days. By 48 – 96 hours after treatment the average half life was 2.8 days. O-demethylation was revealed as the main metabolic degradation step in man. The rate of Demethylation was higher after oral than i.v. administration. Thus, only 31% of the radioactivity excreted in the urine consisted of unchanged -methyldigoxin after oral administration compared to 51% after i.v. dosing. Only traces of bis- and monoglycosides were excreted in urine, but there were considerable amounts in faeces, where they accounted for more than 35% of the total excretion. Up to 40% of the radioactivity in plasma and urine consisted of polar conjugates during the first 12 hours after administration of -methyldigoxin. The mono- and bisglycosides were identified as the main products of conjugation. During the 7 days approximately 15% of the administered dose was metabolized by splitting off glycosidic bonds and conjugation to polar compounds.Supported by the Deutsche Forschungsgemeinschaft and by Boehringer Mannheim, Germany     

Absorption,metabolism and excretion of darexaban (YM150), a new direct factor Xa inhibitor in humans

1.?The absorption, metabolism and excretion of darexaban (YM150), a novel oral direct factor Xa inhibitor, were investigated after a single oral administration of [¹⁴C]darexaban maleate at a dose of 60?mg in healthy male human subjects.

2.?[¹⁴C]Darexaban was rapidly absorbed, with both blood and plasma concentrations peaking at approximately 0.75?h post-dose. Plasma concentrations of darexaban glucuronide (M1), the pharmacological activity of which is equipotent to darexaban in vitro, also peaked at approximately 0.75?h.

3.?Similar amounts of dosed radioactivity were excreted via faeces (51.9%) and urine (46.4%) by 168?h post-dose, suggesting that at least approximately half of the administered dose is absorbed from the gastrointestinal tract.

4.?M1 was the major drug-related component in plasma and urine, accounting for up to 95.8% of radioactivity in plasma. The N-oxides of M1, a mixture of two diastereomers designated as M2 and M3, were also present in plasma and urine, accounting for up to 13.2% of radioactivity in plasma. In faeces, darexaban was the major drug-related component, and N-demethyl darexaban (M5) was detected as a minor metabolite.

5.?These findings suggested that, following oral administration of darexaban in humans, M1 is quickly formed during first-pass metabolism via UDP-glucuronosyltransferases, exerting its pharmacological activity in blood before being excreted into urine and faeces.     

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%.     

Studies of the different metabolic pathways of antipyrine in man

Summary The pharmacokinetics of antipyrine in plasma and saliva, and urinary excretion of its major metabolites, were studied following i.v. and oral administration of antipyrine 500 mg to 6 healthy volunteers. Data from both plasma and saliva showed that the oral bioavailability of antipyrine given as an aqueous solution was complete. The saliva/plasma concentration ratio was constant with time from about 3 h onwards, with a mean value of 0.87 after oral and 0.91 after i.v. administration. It is concluded that the pharmacokinetic parameters of antipyrine can be satisfactorily established on the basis of salivary data, although the volume of distribution and clearance values are then slightly too high. After i.v. administration, 3.8±1.9% of the dose was excreted in urine as unchanged antipyrine in 48h, 24.9±6.3% as 4-hydroxyantipyrine, 16.5±3.2% as norantipyrine, 13.0±2.2% as 3-hydroxymethyl-antipyrine and 5.8±1.0% as 3-carboxy-antipyrine. No significant differences were observed following oral administration. The half-lives calculated from the linear part of the urinary excretion rate curves of the metabolites were about the same for oral and i.v. administration, and were of the same order of magnitude as the elimination half-life of parent drug in plasma and saliva. It is important for determination of the ultimate metabolite ratio that urine is collected for at least 36h, because there is a delay in the excretion of 3-hydroxymethyl-antipyrine in urine.     

Oral absorption,metabolism and excretion of 1-phenoxy-2-propanol in rats

1. This study was designed to determine the absorption, metabolism and excretion of 1-phenoxy-2-propanol in Fischer 344 rats following oral administration in an effort to bridge data with other propylene glycol ethers.

2. Rats were administered a single oral dose of 10 or 100?mg?kg^{?1 14}C-1-phenoxy-2-propanol as a suspension in 0.5% methyl cellulose ether in water (w/w). Urine was collected at 0–12, 12–24 and 24–48?h and faeces at 0–24 and 24–48?h post-dosing and the radioactivity was determined. Urine samples were pooled by time point and dose level and analysed for metabolites using LC/ESI/MS and LC/ESI/MS/MS.

3. The administered doses were rapidly absorbed from the gastrointestinal tract and excreted. The major route of excretion was via the urine, accounting for 93 ± 5% of the low and 96 ± 3% of the high dose. Most of the urinary excretion of radioactivity occurred within 12?h after dosing; 85 ± 2% of the low and 90 ± 1% of the high dose. Total faecal excretion remained 4. Rapid oral absorption, metabolism and urinary excretion of 1-phenoxy-2-propanol in rats were similar to other propylene glycol ethers.     

The absorption, tissue distribution and excretion of di-n-octyltin dichloride in rats

In this study the absorption, tissue distribution and excretion of 14C-labeled di-n-octyltin dichloride ([14C]DOTC) in rats were investigated after oral and intravenous (i.v.) administration. Although after i.v. administration with 1.2 mg [14C]DOTC/kg body weight the tissue radioactivity was about 3-4 times higher than after oral administration with 6.3 mg [14C]DOTC/kg body weight, the relative tissue accumulation was found to be the same after the oral and i.v. dosage. The highest amount of radioactivity was found in liver and kidney, and to a lesser degree in adrenal, pituitary and thyroid glands. The lowest activity was recovered from blood and brain. No selective accumulation was observed in thymus, although it has been reported that thymus atrophy is the most sensitive parameter of DOTC toxicity in rats. For all tissues a time dependent decrease in radioactivity was found, except for kidney. The excretion of radioactivity in feces and urine was determined after a single i.v. or oral dose of 1.2 and 2 mg [14C]DOTC, respectively. After i.v. administration most of the radioactivity was excreted in the feces which was characterized by a biphasic excretion pattern. In orally treated rats more than 80% of the radioactivity was already excreted in the feces during the first day after administration. This indicated that only a small part of the DOTC was absorbed, which was calculated to be approximately 20% of the dose. Similar half-life values of 8.3 and 8.9 days were obtained from the fecal excretion of radioactivity after the i.v. and oral administration, respectively. The urinary excretion of radioactivity appeared to be independent of the body burden, since the daily amount of radioactivity excreted in urine was nearly the same independent of the route of administration as well as the time after administration.     

On the fate of furosemide in man

Summary ³⁵S-furosemide was administered orally (n=7) or i.v. (n=2) to healthy subjects. The average gastrointestinal uptake estimated by comparison of the urinary recovery of label and the areas under the plasma curves after the two routes of administration was 65%. The half life of radioactivity in the plasma after oral³⁵S-furosemide was 90 ± 17 min (estimated on the slope between 2 and 6 h); the corresponding figure after³⁵S-furosemide i.v. was 47–53 min (slope 0.5–4 h). There was probably a slower phase after 4–6 h. Fractionation of labelled material in urine from two subjects demonstrated that approximately two thirds of the label recovered at 24 h had the same chromatographic properties as furosemide. A major part of the metabolite(s) was probably furosemide glucuronide. There was no evidence that 4-chloro-5-sulfamoylanthranilic acid was formed in man. The total urinary recovery of label (5–7 d) after oral and intravenous administration was 55.1±3.2 (mean±SD) and 82–84%, respectively. After³⁵S-furosemide i.v., 6–9% of the label was recovered in faeces, and it could not be accounted for solely by biliary excretion of furosemide.     

Metabolism and disposition of the dipeptidyl peptidase IV inhibitor teneligliptin in humans

Abstract

1. The absorption, metabolism and excretion of teneligliptin were investigated in healthy male subjects after a single oral dose of 20?mg [¹⁴C]teneligliptin.

2. Total plasma radioactivity reached the peak concentration at 1.33?h after administration and thereafter disappeared in a biphasic manner. By 216?h after administration, ≥90% of the administered radioactivity was excreted, and the cumulative excretion in the urine and faeces was 45.4% and 46.5%, respectively.

3. The most abundant metabolite in plasma was a thiazolidine-1-oxide derivative (designated as M1), which accounted for 14.7% of the plasma AUC (area under the plasma concentration versus time curve) of the total radioactivity. The major components excreted in urine were teneligliptin and M1, accounting for 14.8% and 17.7% of the dose, respectively, by 120?h, whereas in faeces, teneligliptin was the major component (26.1% of the dose), followed by M1 (4.0%).

4. CYP3A4 and FMO3 are the major enzymes responsible for the metabolism of teneligliptin in humans.

5. This study indicates the involvement of renal excretion and multiple metabolic pathways in the elimination of teneligliptin from the human body. Teneligliptin is unlikely to cause conspicuous drug interactions or changes in its pharmacokinetics patients with renal or hepatic impairment, due to a balance in the elimination pathways.     

R—hap在大鼠体内的组织分布，排泄及药动学研究

测定R-hap在健康Wistar大鼠体内的组织分布，排泄及药动学参数。R-hap采用IODO-GEN标记，测定单次推注给药后^125I-R-hap的组织分布，尿、粪及胆汁的排泄情况。^125I-R-hap药动学参数也是在单次推注给药后测定。R-hap在体内广泛分布，在大部分器官中快速消除。其中肾的含量最高，脂肪的含量最低。累计排泄率为71．81％±2．15％（48小时）及94．71％±1．50％（120小时）。经尿排泄为主要的排泄途径，给药后120小时，尿及粪的累计排泄率分别为80．64％±1．47％，14．07％±0．95％。平均给药时曲线下面积为（8818．4±576．1）Bq／h／mL。R-hap的组织分布，排泄及药动学参数的结果为未来的临床试验设计提供了参考依据。     

Oral absorption, metabolism and excretion of 1-phenoxy-2-propanol in rats

1. This study was designed to determine the absorption, metabolism and excretion of 1-phenoxy-2-propanol in Fischer 344 rats following oral administration in an effort to bridge data with other propylene glycol ethers. 2. Rats were administered a single oral dose of 10 or 100 mg kg(-1) 14C-1-phenoxy-2-propanol as a suspension in 0.5% methyl cellulose ether in water (w/w). Urine was collected at 0-12, 12-24 and 24-48 h and faeces at 0-24 and 24-48 h post-dosing and the radioactivity was determined. Urine samples were pooled by time point and dose level and analysed for metabolites using LC/ESI/MS and LC/ESI/MS/MS. 3. The administered doses were rapidly absorbed from the gastrointestinal tract and excreted. The major route of excretion was via the urine, accounting for 93 +/- 5% of the low and 96 +/- 3% of the high dose. Most of the urinary excretion of radioactivity occurred within 12 h after dosing; 85 +/- 2% of the low and 90 +/- 1% of the high dose. Total faecal excretion remained < 10%. Rats eliminated the entire administered dose within 48 h after dosing; recovery of the administered dose ranged from 100 to 106%. Metabolites tentatively identified in urine were conjugates of phenol (sulphate, glutathione) with very low levels (< 2%) of hydroquinone (glucuronide), conjugates of parent compound (glucuronide, sulphate) and a ring-hydroxylated metabolite of parent. There was no free parent compound or phenol in non-acid-hydrolysed urine. In acid-hydrolysed urine, 61% of the dose was identified as phenol and 13% as 1-phenoxy-2-propanol. Although the parent compound was stable to acid hydrolysis, some of the phenol in acid hydrolysed urine may have arisen from degradation of acid-labile metabolite(s) as well as hydrolysis of phenol conjugates. 4. Rapid oral absorption, metabolism and urinary excretion of 1-phenoxy-2-propanol in rats were similar to other propylene glycol ethers.     

Further absorption studies with the anti-diarrhoeal agent ethacridine lactate in the dog

2-Ethoxy-6,9-diaminoacridine lactate (ethacridine lactate, Rivanol, Metifex) has been administered orally to the dog once daily for 14 days, tritium labelled matterial having been given on days 1 and 14. The extent and rates of urinary excretion of radioactivity and the peak plasma levels and total radioactivity half-lives following the radiolabelled doses on days 1 and 14 were essentially the same. There was no significant change following multiple dosing in the level of urinary acridine-like material as determined fluorimetrically, which compared to approximately 0.01% of the dose found in the 0--24 h urine. It was concluded that, following oral administration of 3H-ethacridine lactate (5 mg/kg), less than 0.1% of the dose is absorbed as acridine-like material. Multiple dosing for 14 days does not alter this very low degree of oral absorption. In a separate study tritiated ethacridine lactate (30 microgram/kg) was administered i.v. to the dog. Approximately 84% of the radioactivity was eliminated in the 0--72 h post dose period, the majority of it being excreted via the faeces. There was a rapid loss of radioactivity from the plasma, followed by a long terminal phase in which acridine-like material was estimated to have a half-life of about 15 h.