Dose‐dependent pharmacokinetics and first‐pass effects of mirodenafil,a new erectogenic,in rats

The pharmacokinetics of mirodenafil and its two metabolites, SK3541 and SK3544, after intravenous (5, 10, 20 and 50 mg/kg) and oral (10, 20 and 50 mg/kg) administration of mirodenafil, and the first‐pass effect of mirodenafil after intravenous, oral, intraportal, intragastric and intraduodenal (20 mg/kg) administration of mirodenafil were evaluated in rats. The pharmacokinetics of mirodenafil and SK3541 were dose‐dependent after both intravenous and oral administration of mirodenafil due to the saturable hepatic metabolism of mirodenafil. After oral administration of mirodenafil, approximately 2.59% of the oral dose was not absorbed, the F value was approximately 29.4%, and the hepatic and gastrointestinal first‐pass effects of mirodenafil were approximately 21.4% and 54.3% of the oral dose, respectively. The low F value of mirodenafil in rats was mainly due to considerable hepatic and gastrointestinal first‐pass effects in rats. The equilibrium plasma‐to‐blood cell partition ratios of mirodenafil were independent of the initial blood mirodenafil concentrations of 1–10 µg/ml; the mean values were 1.08–1.21. The plasma binding values of mirodenafil to rat plasma was 87.8%. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of water deprivation for 72 hours on the pharmacokinetics of DA-7867, a new oxazolidinone, in rats

The pharmacokinetic parameters of DA-7867 were compared after intravenous and oral administration at a dose of 10 mg/kg in control rats and in rats with water deprivation for 72 h (rat model of dehydration). After intravenous administration in the rat model of dehydration, the Cl(nr) (0.654 versus 0.992 ml/min/kg) and Cl(r) (0.0273 versus 0.0784 ml/min/kg) values were significantly slower than in the controls. The slower Cl(nr) could be due mainly to a significantly smaller total amount of unchanged DA-7867 recovered from the gastrointestinal tract at 24 h (GI(24 h): 5.16% versus 9.21% of intravenous dose) due to impaired liver function in the rat model of dehydration. The slower Cl(r) could be due mainly to a significantly smaller 24 h urinary excretion of unchanged drug (Ae(0-24 h): 4.41% versus 7.75% of intravenous dose) due to urine flow rate-dependent Cl(r) of DA-7867 in the rat model of dehydration. Hence, the Cl was significantly slower in the rat model of dehydration (0.677 versus 1.07 ml/min/kg). After intravenous administration in the rat model of dehydration, the V(ss) of DA-7867 was significantly smaller than in the controls (396 versus 506 ml/kg) due mainly to significantly smaller free (unbound to plasma proteins) fractions of DA-7867 in plasma (6.90% versus 29.2%) in the rat model of dehydration. After oral administration in the rat model of dehydration, the AUC was significantly greater than that in controls (10800 versus 7060 microg min/ml) due mainly to a significantly smaller Ae(0-24 h) than in controls (3.50% and 6.17% of oral dose).     

Effects of acute renal failure on the pharmacokinetics of DA-7867, a new oxazolidinone, in rats

The pharmacokinetic parameters of DA-7867 were compared after intravenous and oral administration at a dose of 10 mg/kg to control rats and rats with acute renal failure induced by uranyl nitrate (rats with U-ARF). After intravenous administration in rats with U-ARF, the time-averaged total body clearance (Cl) was significantly faster (2.45 versus 0.932 ml/min/kg) than controls due to significantly faster nonrenal clearance (2.25 versus 0.855 ml/min/kg) in rats with U-ARF. The faster nonrenal clearance could be due to significantly greater gastrointestinal (including biliary) excretion; the amount of unchanged DA-7867 recovered from the entire gastrointestinal tract at 24 h was significantly greater (30.3% versus 9.38% of intravenous dose) in rats with U-ARF. In rats with U-ARF, the Vss was significantly larger (1420 ml/kg compared with 580 ml/kg), but this was not due to a difference in plasma protein binding; the values were comparable between the two groups of rats. After oral administration to rats with U-ARF, the total area under the plasma concentration-time from time zero to time infinity (AUC) of DA-7867 was significantly smaller than the controls (2560 microg min/ml versus 7440 microg min/ml), and this was not due mainly to a decrease in absorption from the gastrointestinal tract in rats with U-ARF.     

Effects of bacterial lipopolysaccharide on the pharmacokinetics of DA-7867, a new oxazolidinone, in rats

Pharmacokinetic parameters of DA-7867 were compared after intravenous and oral administration at a dose of 10 mg/kg to control rats and rats pretreated with Klebsiella pneumoniae lipopolysaccharide (KPLPS). After intravenous administration of DA-7867 at a dose of 10 mg/kg to 10 rats, metabolism of DA-7867 was minimal; however, the urinary and gastrointestinal excretion of DA-7867 were approximately 85% of intravenous dose when collected for up to 14 days. After intravenous administration to rats pretreated with KPLPS, the AUC was significantly greater (14,100 versus 9810 microg x min/mL), and this could be due to significantly slower total body clearance (CL, 0.709 versus 1.02 mL/min/kg). The slower CL in the rats could be due to significantly smaller fecal excretion of DA-7867 for up to 14 days (41.1 versus 58.8% of intravenous dose of DA-7867) because urinary excretion of DA-7867 was not significantly different between two groups of rats. After oral administration, the AUC values were not significantly different between two groups of rats and this was mainly due to decrease in absorption from the gastrointestinal tract in rats pretreated with the KPLPS (approximately 82 and 95% of oral dose were absorbed for rats with KPLPS and control rats, respectively).     

Pharmacokinetics,bioavailability and tissue distribution of geniposide following intravenous and peroral administration to rats

In order to characterize the pharmacokinetics, bioavailability and tissue distribution of geniposide following intravenous and peroral administration to rats, a reliable gradient HPLC‐based method has been developed and validated. After p.o. administration of geniposide, the peak concentration of geniposide in plasma occurred at 1 h and plasma geniposide was eliminated nearly completely within 12 h. The AUC_{0→ ∞} values of geniposide were 6.99 ± 1.27 h · µg/ml and 6.76 ± 1.23 h · µg/ml after i.v. administration of 10 mg/kg and p.o. administration of 100 mg/kg of geniposide, respectively. The absolute oral bioavailability (%F) of geniposide was calculated as 9.67%. After p.o. administration of geniposide, the AUC_0→4h values in tissues were in the order of kidney > spleen > liver > heart > lung > brain. This study improved the understanding of the pharmacokinetics, bioavailability and tissue distribution of geniposide in rats and may provide a meaningful basis for clinical application of such a bioactive compound of herbal medicines. Copyright © 2013 John Wiley & Sons, Ltd.     

Excretion and metabolism of DA-7867, a new oxazolidinone, in rats

Almost negligible hepatic metabolism (minor role of liver for the metabolism) and extensive urinary and fecal excretion of DA-7867 were investigated after intravenous administration at a dose of 10 mg/kg to rats. Pharmacokinetic parameters, especially nonrenal clearances of DA-7867, were very similar between control rats and rats pretreated with SKF 525-A, a nonspecific inhibitor of CYP isozymes, in rats. Similar results were also obtained between control rats and rats with liver cirrhosis induced by dimethylnitrosamine. Hepatic first-pass effect of DA-7867 was almost negligible in rats; the areas under the plasma concentration-time curve from time zero to time infinity of DA-7867 were not significantly different between intravenous and intraportal administration. The above data indicated that liver had almost negligible metabolic activity for DA-7867 in rats. Since metabolism of DA-7867 was not considerable in rats, urinary and fecal excretion of the drug was measured for up to 14 days in ten rats. Fecal excretion was the major route for elimination of DA-7867 in rats; approximately 85.0% of intravenous dose of DA-7867 at 10 mg/kg was recovered from urine (17.0% of intravenous dose), feces (64.0% of intravenous dose), washings of the metabolic cage (3.16% of intravenous dose), and entire gastrointestinal tract (0.421% of intravenous dose).     

Comparative study on the disposition of a new orally active dopamine prodrug, N-(N-acetyl-L-methionyl)-O,O-bis(ethoxycarbonyl)dopamine (TA-870) and dopamine hydrochloride in rats and dogs

The pharmacokinetics of a dopamine derivative, TA-870, and dopamine (DA) after oral administration are compared in rats and dogs. The maximum concentrations of free DA in plasma after oral administration of TA-870 were 150 ng/ml in the rat (30 mg/kg) and 234 ng/ml in the dog (33.5 mg/kg). On the contrary, the maximum plasma concentrations after oral administration of DA at an equimolar dose to TA-870 were 12 ng/ml in the rat (12 mg/kg) and 36 ng/ml in the dog (13.5 mg/kg). The AUC values of free DA in plasma after oral administration of TA-870 (30 or 33.5 mg/kg) were 4-6 times higher than those after DA in both animal species. The peak tissue levels of radioactivity in rats after oral administration of [14C]TA-870 (30 mg/kg) were also 5.5 times higher in the liver and 1-2 times higher in other tissues than those after [14C]DA dose (12 mg/kg). In rats, the main excretion route of radioactivity after oral administration of [14C]TA-870 or DA was via the urine. The total recoveries of radioactivity in the urine and feces were 91-96% of the dose within 24 hr for both compounds. Biliary excretion in rats accounted for 19.8% of the dose of [14C]TA-870 and 12.6% of the dose of [14C]DA within 24 hr. These results demonstrate that TA-870 was well absorbed from the digestive tract, extensively metabolized to dopamine, and proved to be an orally usable dopamine prodrug.     

Gender differences in the hepatic elimination and pharmacokinetics of lobeglitazone in rats

The pharmacokinetics of lobeglitazone (LB) was studied after intravenous administration at a dose of 1 mg/kg and oral administration at doses of 0.1, 1 and 10 mg/kg in male and female rats. The area under the plasma concentration–time curve from time zero to infinity (AUC_inf) after intravenous administration was approximately 7.1 times higher in female rats than in male rats. In addition, the AUC_inf in the case of oral administration was at least 4.4 times higher in female rats and appeared to increase in proportion to the dose in both genders. The in vitro half‐lives were 18.8 ± 4.45 min and 60.7 ± 11.2 min, as evidenced by incubating liver microsomes obtained from male and female rats, respectively. As a result, the estimated CL_int for LB for male rat liver microsomes (0.0779 ± 0.0233 ml/min/mg protein) was much higher than that for female rat liver microsomes (0.0233 ± 0.0039 ml/min/mg protein, p < 0.05). These observations suggest that there are gender differences in the pharmacokinetics and hepatic metabolism for LB in rats. Copyright © 2015 John Wiley & Sons, Ltd.     

In‐situ absorption,protein binding and pharmacokinetic studies of S002‐853, a novel antidiabetic and antidyslipidaemic flavone derivative in rats

Objectives The aim of the study was to investigate the in‐situ absorption kinetics, plasma protein binding and pharmacokinetic characteristics of a novel synthetic flavone derivative, S002‐853, which shows pronounced antidiabetic and antidyslipidaemic activity. Methods Quantification of S002‐853 in plasma was performed by the LC‐MS/MS method and in‐situ sample analysis was carried out by the HPLC‐UV method. Key findings The absorption rate constant was 0.274/h in a mild alkaline environment, which S002‐853 experiences in the intestine following oral dose administration. Plasma protein binding was found to be 26.37 ± 2.58% at a concentration of 1 μg/ml. The pharmacokinetic parameters were determined in male rats after administration of a single 40 mg/kg oral dose and 10 mg/kg intravenous dose. The peak plasma concentration (C_max) was found to be 60.93 ng/ml at 8 h after oral administration. Irregular concentration–time profiles with secondary peaks were observed after oral dose administration. The elimination half‐life of the compound was 19.56 h and 16.30 h after oral and intravenous doses, respectively. Comparison of the AUC after oral and intravenous dosing of S002‐853 indicates that only about 29.48% (bioavailability) of the oral dose reaches the systemic circulation. Conclusions In‐situ study of S002‐853 shows slow absorption from the gastrointestinal tract. S002‐853 also shows low plasma protein binding. The pharmacokinetic parameters after oral and intravenous dose reveal low oral bioavailability and high mean residence time.     

Pharmacokinetics,biodistribution and bioavailability of isoliquiritigenin after intravenous and oral administration

Context: Isoliquiritigenin (ISL) has been shown to exhibit a variety of biological activities. However, there is little research on the pharmacokinetic behavior and tissues distribution of ISL.

Objective: Pharmacokinetics, biodistribution and bioavailability of ISL after intravenous and oral administration were determined by systematic investigation in Sprague–Dawley rats.

Materials and methods: ISL was dissolved in medicinal ethanol-Tween 80–0.9% sodium chloride saline in a volume ratio of 10:15:75. The ISL solution was injected in rats via a tail vein at a single dose of 10, 20 and 50?mg/kg and administered orally in rats at a single dose of 20, 50 and 100?mg/kg, respectively. Blood samples were collected at time intervals of 0.08, 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 6, 8 and 12?h after intravenous injection. Tissues of interests in mice were collected immediately at each determined time point (0.5, 1, 2, 3 and 6?h) after cervical dislocation.

Results: The dose-normalized AUC values were 7.3, 7.6 and 8.7?μg?×?h/ml (calculated based on the dose of 10?mg/kg) for intravenous doses of 10, 20 and 50?mg/kg, respectively. The elimination half-lifes (t_1/2λ) were 4.9, 4.6 and 4.8?h at 10, 20 and 50?mg/kg intravenous doses, respectively. The F values were 29.86, 22.70, 33.62% for oral doses of 20, 50 and 100?mg/kg, respectively. Liver, heart and kidney were major distribution tissues of ISL in mice. The plasma protein binding of ISL in rats was 43.72%.

Conclusion: The work may useful for further study of the bioactive mechanism of ISL.     

Effects of protein-calorie malnutrition on the pharmacokinetics of DA-7867, a new oxazolidinone, in rats

The pharmacokinetic parameters of DA-7867, a new oxazolidinone, were compared after intravenous and oral administration at a dose of 10 mg x kg(-1) to control rats and rats with protein-calorie malnutrition (rats with PCM). After intravenous administration of 10 mg x kg(-1) DA-7867 to rats, metabolism of the drug was not considerable and after 14 days approximately 85.0% of the dose was recovered as unchanged drug from urine and faeces. After intravenous administration to rats with PCM, the area under the plasma concentration-time curve from time zero to time infinity (AUC) was significantly smaller (10800 vs 6990 microg min x mL(-1)) compared with control rats. This may have been due to significantly faster total body clearance (CL, 0.930 vs 1.44 mL x min(-1) x kg(-1)). The faster CL in PCM rats could have been due to significantly faster non-renal clearance (0.842 vs 1.39 mL x min(-1) x kg(-1) due to significantly greater gastrointestinal (including biliary) excretion; the amount of unchanged DA-7867 recovered from the entire gastrointestinal tract at 24 h was significantly greater (1.19 vs 4.28% of intravenous dose)) because the renal clearance was significantly slower in PCM rats (0.0874 vs 0.0553 mL x min(-1) x kg(-1)). After oral administration to PCM rats, the AUC was significantly smaller compared with control rats (7900 vs 4310 microg x min x mL(-1)). This could have been due to a decrease in absorption from the gastrointestinal tract.     

Pharmacokinetics and tissue distribution of the new gastrokinetic agent cisapride in rat, rabbit and dog

The plasma kinetics and tissue distribution of the gastrokinetic (+/-)-cis-4-amino-5-chloro-N-[1-(3-(4-fluorophenoxy)propyl]-3-methoxy-4- piperidinyl]-2-methoxybenzamide monohydrate (cisapride, R 51 619) have been studied in the rat, rabbit and dog. After intravenous administration to rats (5 mg/kg) and dogs (0.63 mg/kg) plasma level-time curves were adequately fitted to a two-compartmental model. The plasma clearance (ClT) and volume of distribution (Vdss) averaged 91 ml/min.kg and 4.7 l/kg in the rat and 4.2 ml/min.kg and 0.82 l/kg in the dog, respectively. Following oral administration, cisapride was rapidly and almost completely absorbed from the gastrointestinal tract in rats and rabbits. The absorption was somewhat slower in the dog. In male rats the plasma radioactivity was mainly due to metabolites, unaltered cisapride representing on average 10% of the total radioactivity. A markedly larger proportion of the parent drug was seen in female rats. Linear plasma kinetics were observed for cisapride in the dose range of 10 to 160 mg/kg. Similarly in the dog, linearity was observed after oral administration in the range of 0.31 to 10 mg/kg. The plasma kinetics remained unaltered on repeated oral doses of 10 mg/kg to rats and subchronic intravenous administration at 0.63 mg/kg to dogs. Compared with intravenous administration, the absolute bioavailability of oral cisapride was 23% in rats and 53% in the dog for the drug given in solution. The terminal plasma half-life of cisapride was about 1-2 h in the rat and about 4-10 h in the rabbit and dog.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pharmacokinetics of L-FMAUS, a new antiviral agent, after intravenous and oral administration to rats: contribution of gastrointestinal first-pass effect to low bioavailability

The pharmacokinetics of L-FMAUS after intravenous and oral administration (20, 50 and 100 mg/kg) to rats, gastrointestinal first-pass effect of L-FMAUS (50 mg/kg) in rats, in vitro stability of L-FMAUS, blood partition of L-FMAUS between plasma and blood cells of rat blood, and protein binding of L-FMAUS to 4% human serum albumin were evaluated. L-FMAUS is being evaluated in a preclinical study as a novel antiviral agent. Although the dose-normalized AUC values of L-FMAUS were not significantly different among the three doses after intravenous and oral administration, no trend was apparent between the dose and dose-normalized AUC. After oral administration of L-FMAUS (50 mg/kg), approximately 2.37% of the oral dose was not absorbed, and the extent of absolute oral bioavailability (F) was approximately 11.5%. The gastrointestinal first-pass effect was approximately 85% of the oral dose. The first-pass effects of L-FMAUS in the lung, heart and liver were almost negligible, if any, in rats. Hence, the small F of L-FMAUS in rats was mainly due to the considerable gastrointestinal first-pass effect. L-FMAUS was stable in rat gastric juices. The plasma-to-blood cells partition ratio of L-FMAUS was 2.17 in rat blood. The plasma protein binding of L-FMAUS in rats was 98.6%.     

Pharmacokinetics of mebudipine, a new calcium antagonist, following single intravenous and oral administrations in rats

The pharmacokinetics of a new calcium antagonist, mebudipine, was studied after a single intravenous (0.5 mg/kg) and oral (10 mg/kg) administration to rats. After intravenous dosing, the plasma concentration of mebudipine declined biexponentially with a terminal half-life of 2.84 h. The blood clearance was 1.67 l/h/kg and the volume of distribution at steady state was found to be 6.26 l/kg. After oral dosing (10 mg/kg), the C(max) of mebudipine was 25.9+/-9.79 ng/ml. The oral bioavailability was low (< 2%) suggesting a marked first-pass effect. The distribution of mebudipine into some tissues such as brain, heart, liver and kidney following intravenous administration (0.5 mg/kg) was studied and a rapid distribution of mebudipine into these tissues was found. It was concluded that brain, heart, liver and kidney are in the same compartment as plasma (central).     

Dose-independent pharmacokinetics of torasemide after intravenous and oral administration to rats

After intravenous (at doses of 1, 2, 5, and 10 mg/kg) and oral (at doses of 1, 5, and 10 mg/kg) administration of torasemide, the pharmacokinetic parameters were dose-independent. Hence, the extent of absolute oral bioavailability (F) was also independent of oral doses; the values were 95.6, 98.8, and 97.3% for oral doses of 1, 5, and 10 mg/kg, respectively. The high F values indicated that the first-pass (gastric, intestinal, and hepatic) effects of torasemide in rats could be almost negligible. After intravenous administration, the total body clearances of torasemide were extensively slower than the reported cardiac output in rats and hepatic extraction ratio was only 3-4% suggesting almost negligible first-pass effects of torasemide in the heart, lung, and liver in rats. Based on in vitro rat tissue homogenate studies, the tissues studied also showed negligible metabolic activities for torasemide. Equilibrium of torasemide between plasma and blood cells of rat blood reached fast and plasma-to-blood cells concentration ratio was independent of initial blood concentrations of torasemide, 1, 5, and 10 microg/ml; the mean value was 0.279. Protein binding of torasemide to fresh rat plasma was 93.9 +/- 1.53% using an equilibrium dialysis technique.     

Pharmacokinetics of a non-narcotic analgesic,DA-5018, in rats

The pharmacokinetics of a non-narcotic analgesic, DA-5018, were compared after single intravenous (IV), subcutaneous (SC), and oral administrations, and after multiple (seven consecutive days) SC administration to rats. After IV administration of DA-5018, 1, 2, and 5 mg kg⁻¹, the pharmacokinetic parameters of DA-5018 were independent of the dose ranges studied. After oral administration of DA-5018, absorption of the drug from gastrointestinal (GI) tract was fast, but the extent of absolute bioavailability (F) was low; the values were 23.2, 23.0, and 27.3% for 2, 5, and 10 mg kg⁻¹, respectively. After single SC administration of DA-5018, absorption of the drug from the injected site was fast and the extent of absorption was fairly good; the F values were 74.5 and 71.8% for 2 and 5 mg kg⁻¹, respectively. The lower F values after oral administration of DA-5018 to rats could be due to degradation of the drug in rat GI tract and/or considerable first-pass effect. After IV, oral, and SC administration of DA-5018, the drug had a strong affinity to the rat tissues studied as reflected in the greater-than-unity tissue to plasma ratio. After IV, oral, and SC administration of the drug, the biliary and urinary excretion of unchanged DA-5018 were negligible. There was no significant difference in the pharmacokinetics or tissue distribution of DA-5018 between single and multiple SC administration of the drug, 5 mg kg⁻¹, to rats, indicating that there could be no tissue accumulation of the drug after multiple SC administration of the drug to rats. © 1998 John Wiley & Sons, Ltd.     

Vasorelaxant and hypotensive effects of the extract and the isolated flavonoid rutin obtained from Polygala paniculata L

Objectives This study aimed to investigate the in‐vitro and in‐vivo cardiovascular effects of the crude hydroalcoholic extract from Polygala paniculata (HEPP) in rats. Methods The procedures were performed on aortic rings and on normotensive anaesthetized rats. Key findings When tested in endothelium‐intact aorta rings, HEPP (30–1000 µg/ml) produced a significant non‐concentration‐dependent relaxing effect (～40%), which was completely prevented by incubation with L‐NAME (nitric oxide synthase inhibitor), ODQ (soluble guanylate cyclase inhibitor) and partially inhibited by tetraethylammonium (TEA; a non‐selective potassium channel blocker) and charybdotoxin (a large‐ and intermediate‐conductance calcium‐activated potassium channel blocker). In contrast, atropine (a muscarinic receptor antagonist) or pyrilamine(a histamine H₁ receptor antagonist) had no effect. Furthermore, oral administration of HEPP (30–300 mg/kg) in anaesthetized rats caused a dose‐dependent and sustained hypotensive action. This effect was unchanged by atropine or TEA, but was strongly reduced in rats continuously infused with L‐NAME or methylene blue. Moreover, rutin (1–3 mg/kg) administered by an intravenous route also caused a dose‐dependent hypotensive effect in rats. Conclusions Our results demonstrated that the extract obtained from P. paniculata induces potent hypotensive and vasorelaxant effects that are dependent on the nitric oxide/guanylate cyclase pathway. These effects could be related, at least in part, to the rutin contents in this extract.     

Pharmacokinetics of ciprofloxacin. 1st communication: absorption, concentrations in plasma, metabolism and excretion after a single administration of [14C]ciprofloxacin in albino rats and rhesus monkeys

The absorption, disposition, metabolism and excretion of 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-[U-14C]piperazinyl)-3- quinoline carboxylic acid (ciprofloxacin, Bay o 9867; designated tradename: Ciprobay) were studied following a single intraduodenal (rat), oral and intravenous (rat, monkey) administration, respectively, in the dose range 5 to 30 mg/kg body weight. Ciprofloxacin was absorbed partially (30 to 40%) in both species. Peak plasma concentrations of radioactivity were measured approximately 1 h (rat) or 2 h (monkey) after oral dosing. Terminal half-lives ranging from 26 to 44 h were determined for the elimination of radioactivity from the plasma (observation time up to 48 h after dosing). Nearly identical concentrations of the unchanged drug and total radioactivity were found during the first 7 or 8 h for the monkey after intravenous injection and for the rat also after oral administration, respectively. After reaching maximum concentration of 0.25 microgram/ml after administration of 5 mg/kg to rats and 0.88 microgram/ml after dosing with 30 mg/kg to a rhesus monkey, the unchanged drug was eliminated from plasma corresponding to half-lives ranging from 3 h (rat) and 4.4 h (monkey). The radioactivity was rapidly and completely excreted in both species. After intravenous administration about 51% (rat) and 61% (monkey), respectively, was excreted via the kidney. After oral dosing renal excretion amounted to 6-14% (rat) and 30% (monkey), respectively. Maximum residues in the body (exclusive gastrointestinal tract) of 1% of dose occurred in both species. In urine and feces of rats predominantly the unchanged drug and a conjugate were detected.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pharmacokinetics of YJC-10592, a novel chemokine receptor 2 (CCR-2) antagonist,in rats

YJC-10592, a novel chemokine receptor 2 (CCR-2) antagonist, was developed for treating asthma and atopic dermatitis. We studied the pharmacokinetic characteristics of YJC-10592 after intravenous (5, 10 and 20 mg/kg) and oral (100 and 200 mg/kg) administration of the drug to rats. Tissue distribution of YJC-10592 was also evaluated after intravenous administration of YJC-10592, 10 mg/kg, to rats. The pharmacokinetics of YJC-10592 was dose-dependent from 20 mg/kg after intravenous administration to rats. The values of the area under the plasma concentration–time curve from time zero to infinity (AUC) of YJC-10592 were dose-dependent from 20 mg/kg and the time-averaged total body (CL) and nonrenal (CL_NR) clearances of YJC-10592 were significantly lower at dose of 20 mg/kg, suggesting that saturable metabolism may be involved. The absolute bioavailability (F) of YJC-10592 was generally low (<2.55 %) for both oral doses due to incomplete absorption and low urinary excretion. YJC-10592 had a great affinity to all rat tissues studied except brain, which was supported by a relatively high value of the apparent volume of distribution at steady state (V _ss) (890–1385 mL/kg). In conclusion, YJC-10592 showed dose-dependent pharmacokinetics and low F value due to slower elimination and incomplete absorption.     

Pharmacokinetics of caffeic acid phenethyl ester and its catechol‐ring fluorinated derivative following intravenous administration to rats

The pharmacokinetic profiles of caffeic acid phenethyl ester (CAPE) and its catechol‐ring fluorinated derivative (FCAPE) were determined in rats after intravenous administration of 5, 10 or 20 mg/kg for CAPE and 20 mg/kg for FCAPE, respectively. The plasma concentrations of CAPE and FCAPE were measured using a validated liquid chromatography tandem mass spectrometric method. The pharmacokinetic parameters were estimated using non compartmental analysis (NCA) and biexponential fit. The results showed that the area under the plasma concentration‐time curve for CAPE treatment increased in a proportion greater than the increase in dose from 5 to 20 mg/kg of CAPE. Total body clearance values for CAPE ranged from 42.1 to 172 ml/min/kg (NCA) and decreased with the increasing dose of CAPE. Similarly, the volume of distribution values for CAPE ranged from 1555 to 5209 ml/kg, decreasing with increasing dose. The elimination half‐life for CAPE ranged from 21.2 to 26.7 min and was independent of dose. That FCAPE was distributed extensively into rat tissues and eliminated rapidly was indicated by a high value of volume of distribution and similar short elimination half‐life as that of CAPE. Copyright © 2009 John Wiley & Sons, Ltd.