The fate of ticlopidine in the organism. II.--Distribution and elimination of ticlopidine 14C after a single oral administration in the rat

In the Rat, distribution and elimination of Ticlopidine C14 after a single oral dose of 25 mg/kg were studied and compared with that observed after a single intravenous injection of the same dose. The plasma decreases of total radioactivity were found to be identical regardless of adminstration route, indicating almost complete absorption of the labelled molecule. The elimination half-life, which was 1.56 +/- 0.08 days, was equivalent to the half-life measured after intravenous injection, and no difference in tissues distribution was observed. As in the case of intravenous injection, the radioactivity was eliminated principally in the feces and only to a slight degree in the urine.     

Distribution of 14C-ochratoxin A in the rainbow trout (Salmo gairdneri)

The nephrotoxic mycotoxin ochratoxin A was studied in rainbow trout by whole-body autoradiography and scintillation counting using 14C-labelled toxin. After one single intravenous injection of 10 muCi/fish, corresponding to 160 ng toxin/g body weight, the tissue affinity was studied during an eight day period. As soon as 5 min. after injection the concentration of the radioactivity in the blood had dropped to one tenth of that in the kidney and the urinary bladder. The autoradiograms showed two patterns of blackening in the kidney, one diffuse in the pronephros and one very strong spotty blackening in the opistonephros. In addition to the kidney very high concentrations of radioactivity were also noticed in the bile and the pseudobranch. The muscular tissue of treated trouts contained almost no radioactivity during the whole experiment. Chemical analysis revealed that the radioactivity that could be extracted from the organs was mainly ochratoxin A.     

The labelling of motor end-plates in skeletal muscle of mice with 125I tetanus toxin

Summary Twelve hours after injection of ¹²⁵I labelled tetanus toxin into the shank of one hindlimb of mice radioactivity was found in the end-plate region of soleus muscles. The ratio between the radioactivity of the end-plate and the end-plate-free region was 2.5±0.4 S.D. Autoradiographs showed intense labelling of end-plates and a slight but clear labelling of axons.When ¹²⁵I tetanus toxin was injected 3 days after denervation of the soleus muscle the former end-plate region still accumulated a higher radioactivity (ratio 2.0±0.5 S.D.), however, autoradiographs showed a diffuse distribution of labelled tetanus toxin.It can be concluded that tetanus toxin binds to the presynaptic nerve terminal. This binding is not dependent on activity of the nerve terminal or transmitter release.     

Fate and distribution of 3H-labeled T-2 mycotoxin in guinea pigs

T-2 toxin is a potent cytotoxic metabolite produced by the Fusarium species. The fate and distribution of 3H-labeled T-2 toxin were examined in male guinea pigs. Radioactivity was detected in all body tissues within 30 min after an im injection of an LD50 dose (1.04 mg/kg) of T-2 toxin. The plasma concentration of trichothecene molar equivalents versus time was multiphasic, with an initial absorption half-life equal to or less than 30 min. Bile contained a large amount of radioactivity which was identified as HT-2, 4-deacetylneosolaniol, 3'-hydroxy HT-2, 3'-hydroxy T-2 triol, and several more-polar unknowns. These T-2 metabolites are excreted from liver via bile into the intestine. Within 5 days, 75% of the total radioactivity was excreted in urine and feces at a ratio of 4 to 1. The appearance of radioactivity in the excreta was biphasic. Metabolic derivatives of T-2 excreted in urine were T-2 tetraol, 4-deacetylneosolaniol, 3'-hydroxy HT-2, and several unknowns. These studies showed a rapid appearance in and subsequent loss of radioactivity from tissues and body fluids. Only 0.01% of the total administered radioactivity was still detectable in tissues at 28 days. The distribution patterns and excretion rates suggest that liver and kidney are the principal organs of detoxication and excretion of T-2 toxin and its metabolites.     

Synthesis of 14C-ochratoxin A and 14C-ochratoxin B and a comparative study of their distribution in rats using whole body autoradiography.

Methods for preparation of labelled ochratoxin A and B are described. The method for preparation of labelled ochratoxin B involves the synthesis of the azide of ochratoxin beta via the mixed anhydride and subsequent conjugation to labelled phenylalanine to yield 14C-ochratoxin B. The labelled ochratoxins were injected into male Wistar rats and after different survival times they were sacrificed and subjected to whole body autoradiography. The distribution pattern of ochratoxin A in the rat did not differ from that earlier registered for mouse. The previously known, high susceptibility of rats (and not mice) to ochratoxin A-induced cancer could thus not be explained by an accumulation of the toxin in specific cells or organs. The distribution patterns of ochratoxin A and B were almost congruent--the only apparent difference being a much longer retention of the labelled ochratoxin A in the blood compared to ochratoxin B, which was much faster excreted. When analyzing tissue extracts for labelled metabolites only the extracts from the rats injected with ochratoxin B were found to contain easily detectable concentrations, while no metabolites of ochratoxin A were seen.     

The murine disposition and pharmacokinetics of the antineoplastic agent, diaziquone (NSC 182986)

We have studied the murine disposition and pharmacokinetics of diaziquone (AZQ), a new aziridinylbenzoquinone antitumor agent that is currently undergoing clinical trials. 14C-AZQ, dissolved in dimethylacetamide/0.01M phosphate buffer, pH 6.5, 5:95 (v/v), was administered iv to mice at a dosage of 6 mg/kg (18 mg/m2). After injection, mice were killed and plasma and organs were obtained and analyzed for total radioactivity and for chloroform-extractable 14C. Both total plasma radioactivity and chloroform-extractable plasma 14C declined very rapidly. By 3 hr, chloroform-extractable 14C was about 0.2% of its initial concentration. Within 30 min after injection, more radioactivity remained in the aqueous phase than was extracted into chloroform. When analyzed by TLC, all chloroform-extractable radioactivity in plasma as well as in brain, heart, liver, and skeletal muscle co-chromatographed with parent AZQ. Tissue distribution of 14C was extensive. 14C concentrations (dpm/g tissue wet weight) were initially greatest in heart and lung, but by 2 min after injection, were greatest in kidney, and by 10 min were second greatest in liver. Substantial amounts of total and chloroform-extractable 14C were found in brains. By 3 hr after injection, total 14C in all tissues exceeded total 14C in plasma. The apparent volume of distribution of AZQ was approximately 1 ml/g and the total body clearance of AZQ was 0.9 ml/min or 130 ml/min/m2. Extraction of tissues with chloroform showed conversion of AZQ into non-chloroform-extractable metabolites. This conversion was reproduced in vitro by mouse liver homogenate at 37 degrees C but not at 0 degree C.     

Tissue and subcellular localizations of 3H-cyclosporine A in mice

The tissue and subcellular localizations of 3H-cyclosporine A after administration to mice were determined with whole-body autoradiography and scintillation counting of lipid extracts of tissues and subcellular fractions. The radioactivity was widely distributed in the body and the pattern of distribution after oral or parenteral administration was the same, except that tissue levels were generally lower after oral administration. Pretreatment of the animals with a diet containing cyclosporine A for 30 days before the injection of radioactive cyclosporine A did not change the pattern of distribution substantially. No significant radioactivity was found in the central nervous system, except for the choroidal plexus and the area postrema region of the brain. In pregnant mice no passage of radioactivity from the placentas to fetuses was observed after a single injection. 3H-cyclosporine A and/or its metabolites showed a high affinity for the lympho-myeloid tissues, with a marked long-term retention in bone marrow and lymph nodes. There was massive excretion in the intestinal tract after parenteral administration, and the liver, bile, pancreas and salivary glands contained high levels of radioactivity. In the kidney radioactivity was confined to the outer zone of the outer kidney medulla. In liver homogenates no quantitatively significant binding of 3H-cyclosporine A and/or its metabolites to cellular molecules such as proteins, DNA, phospho- or neutral lipids was found. After lipid extraction with organic solvents, almost all radioactivity was recovered in the organic phase.     

Fate and distribution of H-labeled T-2 mycotoxin in guinea pigs

T-2 toxin is a potent cytotoxic metabolite produced by the Fusarium species. The fate and distribution of ³H-labeled T-2 toxin were examined in male guinea pigs. Radioactivity was detected in all body tissues within 30 min after an im injection of an LD50 dose (1.04 mg/kg) of T-2 toxin. The plasma concentration of trichothecene molar equivalents versus time was multiphasic, with an initial absorption half-life equal to or less than 30 min. Bile contained a large amount of radioacivity which was identified as HT-2, 4-deacetylneosolaniol, 3′-hydroxy HT-2, 3′-hydroxy T-2 triol, and several more-polar unknowns. These T-2 metabolites are excreted from liver via bile into the intestine. Within 5 days, 75% of the total radioactivity was excreted in urine and feces at a ratio of 4 to 1. The appearance of radioactivity in the excreta was biphasic. Metabolic derivatives of T-2 excreted in urine were T-2 tetraol, 4-deacetylneosolaniol, 3′-hydroxy HT-2, and several unknowns. These studies showed a rapid appearance in and subsequent loss of radioactivity from tissues and body fluids. Only 0.01% of the total administered radioactivity was still detectable in tissues at 28 days. The distribution patterns and excretion rates suggest that liver and kidney are the principal organs of detoxication and excretion of T-2 toxin and its metabolites.     

Syntheses of 14C-Ochratoxin A and 14C-Ochratoxin B and a Comparative Study of their Distribution in Rats Using Whole Body Autoradiography

Abstract: Methods for preparation of labelled ochratoxin A and B are described. The method for preparation of labelled ochratoxin B involves the synthesis of the azide of ochratoxin β via the mixed anhydride and subsequent conjugation to labelled phenylalanine to yield ¹⁴C-ochratoxin B. The labelled ochratoxins were injected into male Wistar rats and after different survival times they were sacrificed and subjected to whole body autoradiography. The distribution pattern of ochratoxin A in the rat did not differ from that earlier registered for mouse. The previously known, high susceptibility of rats (and not mice) to ochratoxin A-induced cancer could thus not be explained by an accumulation of the toxin in specific cells or organs. The distribution patterns of ochratoxin A and B were almost congruent – the only apparent difference being a much longer retention of the labelled ochratoxin A in the blood compared to ochratoxin B, which was much faster excreted. When analyzing tissue extracts for labelled metabolites only the extracts from the rats injected with ochratoxin B were found to contain easily detectable concentrations, while no metabolites of ochratoxin A were seen.     

Pharmacokinetics and disposition of a new antitumor antibiotic (2'R)-4'-O-tetrahydropyranyladriamycin in rats. Distribution and excretion after multiple administration

The accumulation of (2'R)-4'-O-tetrahydropyranyladriamycin (THP) was studied in rats received intravenous administration of 14C-THP at a dose of 0.5 mg/kg/day for 14 consecutive days by determining blood and tissue levels and the excretion of the radioactivity. The radioactivity levels in plasma and blood cells after the multiple administration were higher than those after single administration. The half-life of the radioactivity after the multiple administration was longer in the blood cells but not in the plasma than the half-life after a single administration. Tissue levels of the radioactivity after the multiple injection were 2 to 4 times as high as the levels after a single injection except for the brain and testes in which a large accumulation of the radioactivity was observed. However, little accumulation of unlabeled THP was found in most tissues when determined by HPLC. The accumulation of radioactivity in tissues, therefore, was due to metabolites of THP. The disposition of 14C-THP was also examined in rats which had previously received unlabeled THP (0.5 mg/kg/day) for 13 days. The pretreatment did not affect the disposition of 14C-THP seriously, although the pretreatment raised tissue levels slightly and a rebound of plasma level of 14C-THP, and lowered the fecal excretion ratio. No induction of hepatic drug metabolizing enzymes was observed in rats after repeated administrations of THP for consecutive 14 days.     

The distribution and excretion of 14C- and 3H-labelled 4-prenyl-1,2-diphenyl-3,5-pyrazolidinedione (DA 2370) in the rat.

The distribution and excretion of radioactivity following a single or multiple oral administration of 3H-and/or 14C-4-prenyl-1,2-diphenyl-3,5-pyrazolidinedione (DA 2370) has been determined in rats. The daily excretion of radioactivity following a single administration (3H and 14C) or multiple doses (3H) fell to less than 1% of the dose in 4 days. A similar fall was observed at the end of 10 days continuous administration. The radioactivity in plasma reached a maximum between 2 and 4 h after administration of the drug (14C). Tissue levels were found to be effectively zero 24 h after administration of the drug for up to 10 days. The very large amounts of radioactivity lost in bile were found to correlate with blood, tissue and faecal levels.     

Intraaxonal and extraaxonal transport of 125I-tetanus toxin in early local tetanus

The distribution of radioactivity in the sciatic nerve, the spinal ganglia, the ventral roots and the spinal cord was studied by means of histoautoradiography after injection of 125I-labelled tetanus toxin into gastrocnemius muscles of cats. In the sciatic nerve the major part of the radioactivity was found in the epineurium, but some axons also contained radioactivity. In the ventral root the radioactivity was strictly confined to a few axons; no radioactivity was found in other parts of the ventral root. In the spinal cord the radioactivity was confined to a few motoneurones where it was found in the soma as well as in the dendrites. Transient cooling of the ventral roots prevented the ascent of radioactivity into the spinal cord. Colchicine and vinblastine, after local application to the sciatic nerve, reduced the amount of radioactivity found in the ventral roots and in the spinal cord. However, the same effect was also obtained but to a lesser degree with lumicolchicine. It is concluded that the intraaxonal compartment is involved in the neural ascent of tetanus toxin into the spinal cord.     

Tissue and Subcellular Localizations of 3H-CyclospoMe A in Mice

Abstract: The tissue and subcellular localizations of ³H-cyclosporine A after administration to mice were determined with whole-body autoradiography and scintillation counting of lipid extracts of tissues and subcellular fractions. The radioactivity was widely distributed in the body and the pattern of distribution after oral or parenteral administration was the same, except that tissue levels were generally lower after oral administration. Pretreatment of the animals with a diet containing cyclosporine A for 30 days before the injection of radioactive cyclosporine A did not change the pattern of distribution substantially. No significant radioactivity was found in the central nervous system, except for the choroidal plexus and the area postrema region of the brain. In pregnant mice no passage of radioactivity from the placentas to fetuses was observed after a single injection. ³H-cyclosporine A and/or its metabolites showed a high affinity for the lympho-myeloid tissues, with a marked long-term retention in bone marrow and lymph nodes. There was massive excretion in the intestinal tract after parenteral administration, and the liver, bile, pancreas and salivary glands contained high levels of radioactivity. In the kidney radioactivity was confined to the outer zone of the outer kidney medulla. In liver homogenates no quantitatively significant binding of ³H-cyclosporine A and/or its metabolites to cellular molecules such as proteins, DNA, phospho- or neutral lipids was found. After lipid extraction with organic solvents, almost all radioactivity was recovered in the organic phase.     

Distribution of [14C]-ciprofloxacin in experimentally induced intramuscular abscesses of rats

Wistar rats were infected by injection of 0.05 ml of a dense oily suspension of Staphylococcus aureus into the posterior thigh muscles of the hind leg. Three days later, solid abscesses had formed which were characterized by a peripheral accumulation of polymorphocytes and incipient central necrosis. At this time, 10 mg/kg of [14C]-ciprofloxacin (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-piperazin-1-ylquino line-3-carboxylic acid, Bay o 9867; designated tradename: Ciprobay) were administered intravenously. The animals were sacrificed at various time intervals after treatment and the distribution of radioactivity was examined by whole-body autoradiography. Five min after administration of ciprofloxacin, the radioactivity was found to be differentially distributed among all organs and tissues, but no radioactivity was detectable in the abscess. Beginning from 1 h post appl., increasing relative amounts of radioactivity were seen inside the abscesses. The relative enrichment as compared to the surrounding muscle tissue was most pronounced after 5 h, indicating that the radioactivity was eliminated more rapidly from the muscle than from the abscess. Some radioactivity was still present in the abscess 8 h after treatment of the animals. The comparison of autoradiograms and corresponding histological sections revealed a distinct affinity of [14C]-ciprofloxacin and/or its potential radioactive metabolites to the areas of inflammatory cellular infiltrates.     

The metabolic disposition of C-labelled carmoisine in the rat after oral and intravenous administration

The absorption, distribution and excretion of the red azo dye carmoisine (Ext. D & C No. 10) was studied in male rats. [14C]Carmoisine was administered in a dose of 200 mg/kg (25 microCi) by gavage or in the same dose (200 mg/kg; 3 microCi) by intravenous injection, and radioactivity was measured in blood, tissue, faeces and urine at different times after dosing. After oral administration of the dye, no radioactivity was detected in the brain, adipose tissue, muscle, testes, spleen or lung, and recovery of the administered activity in faeces and urine was almost complete by 32 hr. The radioactivity profile of the blood indicated rapid but poor absorption of [14C]carmoisine, a maximum radioactivity content corresponding to 0.01% of the dose per ml of blood being reached within 10 min. The decay curve for 14C radioactivity in the blood after iv injection of [14C]carmoisine indicated rapid distribution to the tissues and could be described in terms of a two-compartment mathematical model. The highest levels of radioactivity occurred in the gastro-intestinal tract and liver after the injection but after 24 hr no radioactivity was detectable in these or other tissues. All the radioactivity was recovered in the faeces and urine in the 24 hr following iv injection, the 79% of the dose present in faeces indicating active excretion of the dye and its metabolites in the bile and poor reabsorption from the intestine. The bioavailability of [14C]carmoisine, calculated from the blood-radioactivity curves after oral and iv administration, was less than 10%.     

The distribution of 14C-chloramphenicol in the Japanese quail (Coturnix coturnix japonica)

The distribution of 14C-labelled chloramphenicol after oral and intravenous administration to egg laying Japanese quail was studied by whole-body autoradiography. In the liver, kidneys, gizzard, intestinal contents (bile) and oviduct, the 14C-concentration was higher than that of the blood short time after injection and remained higher than the blood up to 4 days. From 4 hrs, the concentration of 14C in the egg yolks was higher than that of the blood and from 24 hrs the radioactivity in the albumen of the eggs in the oviduct was also higher than that of the blood. The peak concentration in the egg yolk was found in the second egg laid 2-4 days after administration of 14C-chloramphenicol. In the albumen the maximum concentration was found in the first laid egg 24-48 hrs after administration. In the egg yolks, about 30% of the radioactivity represented unchanged chloramphenicol up to 5 days after administration. It was also shown that about 5% of the injected 14C-chloramphenicol was exhaled as 14CO2 during the first 12 hrs and about 37% of the dose was excreted in the combined faeces and urine during the same period of time.     

Distribution of labeled Clostridium perfringens epsilon toxin in mice

The in vivo distribution of labeled Clostridium perfringens epsilon toxin after i.v. administration to mice was investigated. High amounts of radioactivity were found in the kidneys and the brain, and small amounts were in the heart, lungs, liver and stomach. On the other hand, the prior administration of epsilon prototoxin resulted in significant inhibition of the uptake of the radioactivity in the brain, but no effect in the other organs tested. The labeled prototoxin or toxin was dose-dependently accumulated in the brain after i.v. injection. However, the prototoxin inhibited the uptake of the toxin injected within 10 min after the administration of the prototoxin. The prototoxin also inhibited the uptake of labeled bovine serum albumin caused by the toxin in the brain. In the present paper, these data show that the toxin is specifically bound to the brain of mice.     

The absorption and excretion of butylated hydroxyanisole in beagle dogs

Recent studies have indicated that administration of [14C]butylated hydroxyanisole (BHA) to rats, either orally or by intraperitoneal (i.p.) injection, resulted in high retention of radioactivity in the forestomach. The present study was undertaken to investigate the fate of [14C]BHA in non-rodents. 2 Groups of 5-mth-old male beagle dogs were fed a diet containing either 3% or 0.03% BHA for 7 days, and were injected i.p. with 3-tert-[methyl-14C]butyl-4-hydroxyanisole (Amersham International) at a dose of 30 muCi/kg. On the 7th day after [14C]BHA injection, all dogs were killed after fasting overnight, and the liver, kidney, heart, fat tissue and stomach were collected for radioanalysis. An additional 3 beagles served as control group. The fate of BHA after the single i.p. injection of [14C]BHA was examined by the determination of 14C-radioactivity in whole body, blood, urine, feces and several tissues. Blood, urine and feces samples were collected daily for 7 days. Blood samples were collected at intervals for 24 h. BHA was rapidly taken up in the bloodstream, and 50-80% of the total radioactivity was recovered in the urine within 2 days. 15-30% Appeared in the feces within 2 days. The tissue distribution of radioactivity 7 days after [14C]BHA injection showed only a small portion remaining in the stomach (0.16-0.19% of dose/g), liver (0.3-1.7%) and other tissues (0.02%). The radio-activity was almost evenly distributed in the three parts of the stomach (cardia, corpus and pylorus). These findings are in contrast with the previous data in rats that BHA can accumulate in high concentrations in the forestomach.     

葛根有效成分的代谢研究——Ⅱ.14C-黄豆甙元在大鼠体内的吸收、分布和消除

本文采用纸片液体闪烁计数法研究了¹⁴C-黄豆甙元在大鼠体内的吸收、分布和消除。大鼠口服¹⁴C-黄豆甙元30分钟,血液即可测出放射性,6～8小时达高峰,以后缓慢下降。口服给药吸收不完全,由实验推论约有64.6%放射性可被吸收。静脉注射后,血放射性消失曲线分为快、慢两个时相,其生物半衰期分别为13分钟和42分钟。放射性在肾、肝含量最高,血浆、肺、心次之,肌肉、脾、睾丸、脑较低。静脉注射后,¹⁴C主要自尿排出(24小时可排出剂量的71.2%),自粪排出17.4%。口服后24小时可自尿排出34.3%,自粪排出33.1%。胆汁也是一条重要排泄途径,静脉注射后24小时可自胆汁排出剂量的47.4%;口服后相应时间内排出39.1%。本文所得结果与前文应用化学方法所得结果进行比较,表明自消化道、尿、胆汁所回收的放射性主要是黄豆甙元的代谢产物,说明该药在体内的代谢很旺盛。     

Pharmacokinetics of the new pyrimidine derivative NS-7, a novel Na+/Ca2+ channel blocker. 2nd communication: tissue distributions, placental transfer and milk secretion of radioactivity after a single intravenous 14C-NS-7 injection to rats

Tissue distribution, placental transfer and secretion of radioactivity in milk were studied after a single intravenous administration of 0.2 mg/kg of 14C-NS-7 (4-(fluorophenyl)-2-methyl-6-(5-piperidinopentyloxy)pyrimidine hydrochloride, CAS 178429-67-9), a novel Na+/Ca2+ channel blocker, to rats. Except for white fat in male and female rats, tissue radioactivity concentrations 5 min after administration were 2 to 100 times the plasma values, evidence that the drug is widely distributed throughout the body. Five minutes after administration the highest concentration was in the lung followed in order by the adrenal gland, kidney and thyroid gland. Concentrations in the cerebral cortex, striatum and cerebellum, the target organs of NS-7, were similar and 10 to 18 times the plasma concentrations in the male and female rats. Radioactivity concentrations in the lungs decreased rapidly. The pancreas had the highest concentration 2 h after administration. Concentrations decreased in all the tissues examined as the plasma concentration decreased. Maternal and fetal tissue radioactivity concentrations were determined after intravenous injection of 14C-NS-7 to pregnant rats on the 18th day of gestation. Radioactivity was well and rapidly distributed to the maternal tissues, and concentrations in all the tissues tested were higher than the plasma concentrations. In the amniotic fluid, however, the concentration was lower than in the plasma. In all the fetal tissues tested, radioactivity reached a maximum 1 h after administration. The respective fetal blood and whole body concentrations were 2 to 6 and 11 to 13 times the maternal plasma concentration. Of the fetal tissues tested the liver had the highest radioactivity. Decreases in fetal tissue radioactivity concentrations paralleled the decrease in the maternal plasma. More than 90% of the radioactivity present in the placenta and fetal whole body 1 and 24 h after administration was due to the unchanged drug. After intravenous injection of 14C-NS-7 (0.2 mg/kg) to lactating rats on the 10-14th day after parturition, radioactivity was excreted rapidly into the milk, reaching a maximum that was 4 to 6 times the plasma value 1 h after injection.