甲磺酸帕珠沙星与其它抗生素联用于大鼠模型的药动学研究

目的:对甲磺酸帕珠沙星与其它抗生素联合应用的大鼠药代动力学进行对比研究,评价药物间的相互作用及联合用药的合理性.方法:采用一个剂量组,3种用药方案分别单次给药.用药方案:帕珠沙星45 mg/kg;帕珠沙星45 mg/kg加头孢哌酮/舒巴坦180 mg/kg;帕珠沙星45 mg/kg加阿奇霉素45 mg/kg.采用反相HPLC-UV法测定大鼠血药浓度,用DAS软件估算药动学参数,进行统计学分析及临床药效评价.结果:甲磺酸帕珠沙星单用及与头孢哌酮/舒巴坦或阿奇霉素联用的主要药动学参数t1/2、Cmax、tmax、AUC无显著性差异,但帕珠沙星与阿奇霉素联用后清除率(CL)降低及体内驻留时间(MRT)延长,具有统计学意义.结论:帕珠沙星与头孢哌酮/舒巴坦,帕珠沙星与阿奇霉素联用是可行的用药方案.     

Drug interactions between nonsteroidal anti-inflammatory drug and pazufloxacin mesilate,a new quinolone antibacterial agent for intravenous use: convulsions in mice after intravenous or intracerebroventricular administration

Convulsant activity of pazufloxacin mesilate (PZFX mesilate), a new quinolone antibacterial agent for intravenous use, in combination with nonsteroidal anti-inflammatory drug (NSAID) was investigated in mice after intravenous or intracerebroventricular administration. Following results were obtained. 1. In combination with 4-biphenylacetic acid (BPAA) at an oral dose of 100 mg/kg, PZFX mesilate did not induce any convulsions at intravenous doses up to 200 mg/kg. Reference quinolones induced convulsions at the following intravenous doses: Enoxacin (ENX), 3.13 mg/kg or more; norfloxacin (NFLX) and lomefloxacin (LFLX), 6.25 mg/kg or more; ciprofloxacin (CPFX), 50 mg/kg or more; sparfloxacin (SPFX) and temafloxacin (TMFX), 100 mg/kg or more; fleroxacin (FLRX), 200 mg/kg. 2. PZFX mesilate at an intravenous dose of 50 mg/kg did not induce convulsions in mice after oral administration of any of 14 kinds of NSAIDs. It induced convulsions at 200 mg/kg in combination with aspirin at an oral dose of 600 mg/kg, while it did not with the other 13 kinds of NSAIDs. 3. Convulsion-inducing dose of PZFX mesilate after intracerebroventricular administration was 100 mg/body, which was higher than those of reference quinolones (NFLX, CPFX, ENX, LFLX, TMFX, levofloxacin, ofloxacin, FLRX and SPFX) and beta-lactam antibiotics (penicillin G, cefazoline, imipenem/cilastatin and panipenem/betamipron). In addition, concurrent dosing of BPAA (1 microgram/body) did not reduce the convulsion-inducing dose of PZFX mesilate. These results suggest that PZFX mesilate has remarkably weak convulsant activity.     

Attenuation of arbekacin-induced nephrotoxicity in rats by pazufloxacin mesilate

The protective effect of pazufloxacin (PZFX) mesilate, a parenteral quinolone antimicrobial agent, on arbekacin (ABK)-induced nephrotoxicity was evaluated with 8-week-old male Sprague-Dawley rats. Animals were injected with ABK at a dose of 32 mg/kg intramuscularly, or a combination of ABK in the same manner with PZFX mesilate at a dose of 208 mg/kg (160 mg/kg convert to PZFX, active principle of PZFX mesilate) intravenously once a day for 4 days. In consequent, ABK induced increases in protein, beta 2-microglobulin and N-acetyl-beta-(D)-glucosaminidase in urine, and histopathological phospholipidosis in kidneys. The extent of these changes was reduced when ABK was given in a combination with PZFX mesilate. Renal cortex level of ABK increased after an administration of ABK 1 hour to 4 hours; however, the increase was suppressed by coadministration of PZFX mesilate. Taken together, these results suggest that PZFX mesilate has the protective effect on ABK-induced nephrotoxicity, and that this was attributable to a suppression of uptake of ABK in cortical renal tubules.     

Cimetidine pharmacokinetics

The pharmacokinetics of cimetidine was studied in 9 patients at a single intravenous (200 mg) and oral (400 mg) administration. The pharmacokinetic parameters at intravenous administration were calculated according to a two-compartment model. The time-concentration curve after oral drug administration had two maxima between 45 min and 2 hrs with approximately equal concentrations of cimetidine. The main pharmacokinetic parameters of cimetidine were calculated as follows: t1/2 beta = 1.7 h, t1/2 alpha = 0.12 h, Vd = 1.0 1/kg, Cis = 0.43 1/kg/h, Cior = 1.2 1/kg/h, bioavailability 36%. At the course treatment (1 g per day) cimetidine concentration before the morning dose on the 6th and 12th days remains at the same level.     

甲磺酸帕珠沙星与替硝唑在家兔体内的药动学相互作用研究

目的:研究甲磺酸帕珠沙星(PZFX)和替硝唑(TNZ)联用在家兔体内的药动学变化。方法:采用高效液相色谱法测定家兔给药后不同时间PZFX和TNZ血药浓度。药-时数据用3p87程序拟合,计算药动学参数。结果:2药单用与合用时的体内过程均呈二室模型,药-时曲线形态基本一致。PZFX联用TNZ前、后的AUC分别为(620±82.2)、(570±107.9)mg.min.L-1,TNZ联用PZFX前、后的AUC分别为(5507±1013)、(5086±1197)mg.min.L-1;PZFX联用TNZ前、后的t1/2α分别为(7.2±1.4)、(9.9±3.0)min,TNZ联用PZFX前、后的t1/2α分别为(30.5±4.3)、(43.5±5.0)min;PZFX联用TNZ前、后的血浆清除率(CL)分别为(1.4±0.2)、(1.5±0.2)L.h-1,TNZ联用PZFX前、后的CL分别为(0.4±0.1)、(0.5±0.1)L.h-1。2药合用后PZFX可使TNZ的α值增加、t1/2α稍延长,但其余药动学参数比较均无显著性差异(P>0.05)。结论:PZFX与TNZ合用后体内过程未发现明显变化,提示可联合用药,但PZFX有延缓TNZ分布迹象,可能使TNZ起效滞后。     

Phototoxicity studies of pazufloxacin mesilate,a novel parenteral quinolone antimicrobial agent--in vitro and in vivo studies

Phototoxicity of pazufloxacin mesilate (PZFX mesilate), a novel parenteral quinolone antimicrobial agent, were evaluated in vitro and in vivo studies. In vitro, phototoxicity for cultured cells of PZFX, which is active principle of PZFX mesilate, was studied, and stability for long-wavelength ultraviolet (UVA) was examined. In vivo, phototoxicity tests in guinea pigs and rats, and photoallergenicity tests in guinea pigs were conducted. In the phototoxicity test on cultured cells, CHL/IU cells were irradiated UVA of 300-3000 mJ/cm2 in the presence of PZFX, ofloxacin (OFLX), lomefloxacin (LFLX) or sparfloxacin (SPFX) at 10 micrograms/mL. Phototoxic potencies for cultured cells of the quinolones tested were SPFX > LFLX > OFLX > PZFX. In addition, changes in ultraviolet absorption spectrum and residual rate of PZFX, OFLX, LFLX and SPFX were examined after UVA irradiation of 300-3000 mJ/cm2 to each solution. PZFX was stable for UVA compared with OFLX and LFLX. In the phototoxicity test of guinea pigs, each quinolone was administered intraperitoneally daily for 7 days, and UVA of about 11 J/cm2 was irradiated at 30 minutes after the last administration. Dose levels of each quinolone were 65 and 130 mg/kg of PZFX mesilate (dose levels converted to PZFX: 50 and 100 mg/kg), 50 and 100 mg/kg of nalidixic acid (NA), 100 mg/kg of OFLX, enoxacin (ENX), ciprofloxacin (CPFX), LFLX and SPFX. Grade of skin reaction (erythema) at 24 hours after UVA irradiation decreased in the order: SPFX > CPFX > NA > ENX = OFLX > LFLX > PZFX mesilate. Thus, PZFX mesilate was found to have the weakest phototoxicity. In the maximum plasma concentration of quinolones from 0.5 to 2.5 hours after administration, corresponding to the time of UVA irradiation, the concentration of the group administered PZFX mesilate was about 4.1 times higher than that of CPFX group, and about 1.3 times higher than that of SPFX group. The area under the blood concentration-time curve (AUC0.5-2.5) of the group administered PZFX mesilate was the same as that of SPFX group, and about 3.2 times larger than that of CPFX group. These data showed that phototoxicity of PZFX mesilate was also weaker than that of CPFX or SPFX in consideration of AUC0.5-2.5. In the phototoxicity test of rats injected intravenously, no phototoxicity was observed at 130 mg/kg of PZFX mesilate. In the photoallergenicity test of guinea pigs, no photoallergenicity was observed by PZFX mesilate. As mentioned above, from in vitro studies PZFX was found to be stable for UVA irradiation compared with OFLX and LFLX, and phototoxicity for cultured cells of PZFX was weaker than that of SPFX, LFLX or OFLX. In addition, from in vivo studies phototoxicity of PZFX mesilate was found to be weaker than that of NA, OFLX, ENX, CPFX, LFLX or SPFX, and no photoallergenicity was observed. Therefore, photosensitive potency of PZFX mesilate might be less than that of other quinolones.     

Some pharmacokinetic and pharmacodynamic interactions between digoxin and gentamicin.

Some pharmacokinetic and pharmacodynamic interactions between digoxin and gentamicin were studied in experiments on rabbits, guinea-pigs and cats. An increase of digoxin serum levels and changes in some basic pharmacokinetic parameters of digoxin (t1/2 alpha t1/2 beta, AUC, C1) were found in gentamicin-pretreated rabbits, the changes being dependent on the dose and schedule of administration. The most pronounced changes were those in digoxin kinetics during simultaneous 5-day treatment with digoxin (0.035 mg/kg i.v.) and nontoxic (10 and 2 mg/kg) doses of gentamicin. The toxicity of digoxin in guinea-pigs, assessed by administration of lethal doses of digoxin, was increased only after the highest dose of gentamicin (100 mg/kg), while after nontoxic or close to therapeutic doses (10 and 2 mg/kg) of gentamicin, the digoxin toxicity was either unchanged or even decreased. Digoxin decreased the nerve-muscle blocking effect of gentamicin on cat ischiadicus-gastrocnemius preparation. The possible mechanisms involved are discussed.     

Anthropometric data and acetylsalicylic acid pharmacokinetics

The relationship between anthropometric data and pharmacokinetic characteristics of acetylsalicylic acid (ASA) after administration of a single oral dose of 500 mg ASA, an oral and intravenous dose of 500 mg D,L-lysine-mono-acetylsalicylate (Lys-ASA) and an oral dose of 1,000 mg Lys-ASA were evaluated. Individual data from an open, randomized crossover trial in 13 healthy volunteers (age 18-50 years, 6 female, 7 male, height 158-189 cm, weight 45-118 kg) were re-analyzed using a non-compartmental approach. The influence of body weight, height, body surface area and age on pharmacokinetic characteristics (Cmax, Tmax, AUClast, MRTlast, t 1/2, Cl, Vd) was assessed using the multiple regression method and pairwise multiple correlations were calculated. Multiple regression analysis showed significant multiple correlation coefficients of approximately 0.86 for Cmax (500 mg Lys-ASA i.v., 1,000 mg Lys-ASA per os and 500 mg ASA per os), Cl and AUClast (1,000 mg Lys-ASA per os). Standardized regression values (beta) reflected a major contribution for height, weight and body surface area, but age was not a relevant factor. Pairwise comparisons confirmed negative correlations between anthropometric characteristics and Cmax, AUClast and MRTlast and positive correlations between anthropometric data, Cl and Vd. In conclusion, apart from Tmax and t 1/2, all pharmacokinetic characteristics were influenced by body weight, height and body surface area. Whereas repeated administration of high doses in patients with low body weights may give rise to toxic effects, acute single dose administration would not lead to significant under-dosing in tall or stout patients.     

蒙特卡洛模拟评价和优化鲍曼不动杆菌血流感染给药方案

目的 应用蒙特卡洛模拟研究头孢哌酮/舒巴坦、替加环素和多黏菌素B治疗鲍曼不动杆菌血流感染的疗效,预测和评价不同抗菌药物的抗菌效果,进而优化临床给药方案。方法 借助全国血流感染细菌耐药监测联盟(BRICS)平台收集2018—2019年血流感染来源的鲍曼不动杆菌514株,使用文献公开发表的头孢哌酮/舒巴坦、替加环素和多黏菌素B的药动学参数,基于药动学/药效学(PK/PD)理论利用蒙特卡洛模拟法,计算不同给药方案在各特定的MIC值获得的目标概率,即达标概率(PTA)和累积反应分数(CFR),以PTA或CFR≥90%作为临床疗效评价的指标。结果 治疗鲍曼不动杆菌引起的血流感染,头孢哌酮/舒巴坦给药方案4.5 g q6 h在最低抑菌浓度(MIC)≤1 mg/L时,可获得大于或接近90%的目标PTA值,临床分离菌的CFR值为21.53%。替加环素推荐剂量(50 mg q12 h),在MIC≤0.25 mg/L时,可获得大于90%的目标PTA值,100 mg q12 h的给药方案对临床菌株的CFR值为81.04%。多黏菌素B 1.25 mg/kg 1h输注q12 h给药方案,可使MIC≤1 mg/L...     

Pharmacokinetic studies of a novel anticonvulsant, 2-(4-chlorophenyl)amino-2-(4-pyridyl)ethane, in rats.

The pharmacokinetic properties of 2-(4-chlorophenyl)amino-2-(4-pyridyl)ethane (AAP-Cl) were studied in rats after intravenous and oral administration. The blood concentrations of AAP-Cl in rats showed a biexponential decline following intravenous administration of pharmacologic doses ranging from 10 to 100 mg/kg in rats. The terminal elimination half-lives (t((1/2)beta)) of AAP-Cl at the 10, 50 and 100 mg/kg dose levels were 5.80+/-0.30, 6.02+/-0.16 and 6.05+/-0.08 h, respectively. The total clearances (CL) of AAP-Cl at the 10, 50 and 100 mg/kg dose levels were 1.29+/-1.10, 1.38+/-0.07 and 1.33+/-0.13l/(h kg), respectively. The apparent volumes of distribution at steady state (V(ss)) of AAP-Cl at the 10, 50 and 100 mg/kg dose levels were 7.96+/-0.51, 8.24+/-0.31 and 8.17+/-0.43l/kg, respectively. The AUC(0-infinity) increased proportionately to the intravenous bolus dose of AAP-Cl given (10-100 mg/kg). Statistical analysis of the t((1/2)beta), V(ss) and CL values for AAP-Cl between doses indicates that AAP-Cl exhibits dose-independent kinetics (P>0.05). AAP-Cl was absorbed rapidly after an oral dose of 100 mg/kg with peak concentrations (C(max)) in blood (3.5+/-0.33 microg/ml) reached after 30 min of drug administration. The oral bioavailability of AAP-Cl was 19.5+/-3.4% following administration of a single 100 mg/kg dose in rats. Urine analysis indicates that 2.5+/-0.45% of the administered dose of AAP-Cl (100 mg/kg, p.o.) is recovered unchanged in urine within 0-24 h. These findings may be useful in designing new aminoalkylpyridine anticonvulsants with improved efficacy and disposition profiles in animal models of epilepsy.     

Pharmacokinetics, safety, and biologic effects of azithromycin in extremely preterm infants at risk for ureaplasma colonization and bronchopulmonary dysplasia

Ureaplasma spp. respiratory tract colonization is a significant risk factor for bronchopulmonary dysplasia (BPD), a chronic lung disorder in preterm infants. As an initial step preparatory to future clinical trials to evaluate the clinical efficacy of azithromycin to prevent BPD, the authors characterized the pharmacokinetics, safety, and biological effects of a single intravenous dose of azithromycin (10 mg/kg) in preterm neonates (n = 12) 24 to 28 weeks gestation at risk for Ureaplasma infection and BPD. A 2-compartment structural model with the clearance and volume of peripheral compartment (V2) allometrically scaled on body weight (WT) best described the pharmacokinetics of azithromycin in preterm neonates. The estimated parameters were clearance [0.18 L/h × WT(kg)(0.75)], intercompartmental clearance [1.0 L/h], volume of distribution of central compartment [0.93 L], and V2 [14.2 L × WT(kg)]. There were no serious adverse events attributed to azithromycin. A single dose of azithromycin did not suppress inflammatory cytokines or myeloperoxidase activity in tracheal aspirates. These results demonstrated the safety of azithromycin and developed a pharmacokinetic model that is useful for future simulation-based clinical trials for eradicating Ureaplasma and preventing BPD in preterm neonates.     

Effect of vigabatrin and gabapentin on phynytoin pharmacokinetics in the dog.

The study was aimed at investigating whether or not the kinetics of intravenously administered phenytoin (PT) was altered by oral administration of vigabatrin (VGB) or gabapentin (GBP). A group of five beagle dogs were given a daily dose of PT (12 mg/kg, i.v.) for a period of 1 week. On day 8, plasma samples were serially collected over 24 hr. after administration of the PT dose. PT administration was continued with oral supplementary dose of VGB (60 mg/kg) for another week and then plasma samples were collected for analysis of PT levels. The same protocol was followed for the PT (12 mg/kg, i.v.)-GBP (300 mg caps., p.o.) study on a separate group (n = 5) of dogs. Orally administered GBP did not significantly alter the pharmacokinetic parameters of parental PT. VGB, however markedly changed the drug's kinetics as evidenced by a 31% (P = 0.015) reduction in total body clearance (CL) and increase of over 45% in half-life (t1/2), (P = 0.013) and area under the plasma PT concentration-time curve (AUC), (P = 0.044). GBP does not appear to have any pharmacokinetic interaction with PT, while coadministration of VGB and PT results in marked reduction in systemic clearance of the latter in the dog.     

雷公藤内酯醇在Beagle犬体内的药代动力学

雷公藤内酯醇(triptolide，TP)是雷公藤的主要有效成分之一。研究不同剂量TP在Beagle犬灌胃给药时的绝对生物利用度和药代动力学， 可望为其临床研究提供参考。以泼尼松龙作内标， 用乙酸乙酯液液萃取， 建立LC-APCI/MS选择性离子监测方法测定血浆TP浓度。Beagle犬分别静脉注射TP 0.05 mg·kg^-1、 灌胃TP 0.05，0.08和0.1 mg·kg^-1进行药代动力学和绝对生物利用度研究。结果表明， TP在1～200 ng·mL^-1呈良好线性关系(r=0.999 7)，批内和批间精密度RSD均小于10%，准确度在95.0%～105.0%，提取回收率大于75%。静注0.05 mg·kg^-1 TP后，T_1/2β为(2.5±0.8) h。3个剂量灌胃组，T_max，T_1/2α和T_1/2β，经检验无统计学差异。AUC和C_max与剂量之间线性相关。灌胃0.05 mg·kg^-1后，TP在Beagle犬体内绝对生物利用度为(75±17)%。可见，LC-APCI/MS法灵敏、可靠、专属性强，可用来测定Beagle犬血浆TP的浓度；TP在Beagle犬体内消除较快，灌胃给药生物利用度较高。     

Pharmacokinetics of Azithromycin after Single- and Multiple-Doses in Children

Study Objective . To characterize the disposition and tolerance of azithromycin after single and multiple oral doses of 12 mg/kg in children with and without cancer. Design . Open-label, nonrandomized pharmacokinetic study. Setting . Two pediatric hospitals. Patients . Twelve children with cancer admitted to the inpatient unit for empiric antibiotic treatment of febrile neutropenia, and 16 hospitalized patients receiving antibiotic therapy. Interventions . Patients received azithromycin suspension either as a single dose or daily dose every morning for 5 consecutive days. Serial blood samples were collected up to 120 hours after a single dose or during and after multiple doses to characterize the pharmacokinetic parameters estimated for a two-compartment absorption model. Measurements and Main Results . All 28 patients were evaluable for safety. Azithromycin was well tolerated except in one patient with cancer who experienced abdominal cramps and withdrew from the study. Pharmacokinetic results were not determined in five patients because of insufficient concentration-time data. The mean ± SD estimates of oral clearance, terminal half-life, maximum concentration in serum (C_max), and time to achieve C_max in the 23 evaluable patients were 4.83 ± 3.59 L/hour/kg, 54.5 ± 36.4 hours, 318.2 ± 174.5 μg/L, and 2.4 ± 1.1 hours, respectively. These estimates did not differ between single-dose (14 patients) and multiple-dose (9 patients) groups. Pharmacokinetic parameters were not different between the 11 children with cancer and the 12 without cancer. Conclusion . Azithromycin 12 mg/kg results in proportionately higher serum concentrations than previously published results for lower doses (5 mg/kg). Variability in concentration profiles among patients is substantial, and age or other yet unidentified clinical factors may explain some of the differences observed. (Pharmacotherapy 1997;17(5):874–880) In conclusion, C_max, Cl_o, and terminal half-life in these pediatric patients were consistent after single and multiple doses of azithromycin. Moreover, pharmacokinetic parameters were not different between patients with cancer and those with no major concurrent illness. Variability in concentration profiles among patients is substantial, and age or other yet unidentified clinical factors may explain a portion of the differences. The higher dose of azithromycin (12 mg/kg) in this study was well tolerated, and did result in proportionately higher serum concentrations than those reported for lower doses.     

Pharmacokinetics of theophylline in young children with asthma: Comparison of rectal enema and suppositories

Summary Six children, aged 2 months – 4 years, received theophylline 5–6 mg/kg intravenously. Its disposition could be described by a two-compartment open model, the mean serum half life (t_1/2 β) was 3.75 h, i. e., shorter than in adults, but there was a considerable interindividual variation (1.8–7.0 h, in one patient 13.3 h). Thirteen children (2 months – 4 years) received theophylline suppositories in a dose of 3.8–5.0 mg/kg, and ten (6 months – 4 years) in a dose of 8.4–14.5 mg/kg. Absorption was slow (mean half-time 43 min), incomplete and variable (biological availability 8–100%, mean 80%). Only four of the patients given the higher dose and none given the lower dose reached a therapeutic serum concentration (10–20 μg/ml). Nine children (6 months – 4 years) received rectal enemas of theophylline 4.1–9.2 mg/kg. Absorbtion was rapid (mean half-time 5.5 min) and biological availability averaged 100%. Six patients reached a serum concentration within the therapeutic range. Using the mean values of the calculated pharmacokinetic parameters, rectal enemas providing a dose of theophylline of 6–8 mg/kg t. i. d. were computed to give serum concentrations between 8–20 μg/ml, without producing too high a level during the absorption phase.     

Pharmacokinetics of theophylline: a dose-range study.

1 Pharmacokinetics of theophylline were investigated in a group of healthy adult volunteers (non smokers and on xanthine-free diet) following single oral administration of 125, 250, 375 and 500 mg doses as tablets (Theodel). 2 Absorption of theophylline was rapid and followed first-order kinetics. Plasma curves were fitted according to a one compartment open model. 3 There was a linear relationship (P less than 0.001) between plasma Cmax or AUCx values and the administered dose. The analysis of variance showed that the pharmacokinetic parameters of theophylline (t1/2 abs, tmax, t1/2 beta, CL, CLR, Vd and F) were not modified at any dose. 4 Absorption of the drug was complete since the recovery in urine of theophylline (13.7 to 16.8% of the dose) and its major metabolites, 1,3-dimethyluric acid (35 to 42%), 1-methyluric acid (21.3 to 26.7%) and 3-methylxanthine (11.5 to 13.7%), accounted for the administered dose. Some impairment of demethylation to 3-methylxanthine was observed in two subjects, however the percentage of theophylline and its major metabolites excreted in urine was constant for all the four doses. 5 On the basis of these results, after single oral administration, elimination of theophylline followed first-order kinetics in the range of doses investigated (1.62 to 10.42 mg/kg).     

Clinical pharmacokinetics and metabolism of pyrazinamide in healthy volunteers

Eight healthy volunteers were treated with a single dose of pyrazinamide 35 mg/kg. The aim of the study was to evaluate the pharmacokinetic profile of the product and of its metabolites. Urine and blood samples were collected till the 60th h. The kinetics of pyrazinamide could be characterized as follows: CPmax = 50.1 micrograms/ml, tmax less than 1 h, t1/2 alpha = 3.2 h, t1/2 beta = 23 h, U(0-60 h) = 1.6% of the dose administered. The kinetics of the main metabolite, the pyrazinoic acid, gave the following values: CPmax = 66.6 micrograms/ml, tmax = 4 h, t1/2 beta = 12.3 h, U(0-60 h) = 37.5%, of the administered dose.     

HPLC analysis and pharmacokinetic characteristics of 11-hydroxyaclacinomycin X (ID-6105), a novel anthracycline, in rats and beagle dogs

We investigated the pharmacokinetic characteristics of 11-hydroxyaclacinomycin X (ID-6105), a novel anthracycline, after intravenous (i.v.) bolus administration in rats and beagle dogs. We developed an HPLC-based method to analyze ID-6105 levels in plasma, bile, urine, feces, and tissue homogenates and validated the method in a pharmacokinetic study. The plasma concentration of ID-6105 decreased to below the quantifiable limit (0.02 microg/ml) at 4 and 8 h after i.v. administration in rats at doses of 2 and 10 mg/kg, respectively (t(1/2,alpha) and t(1/2,beta) of 0.78 and 17.8 min at a dose of 2 mg/kg, 0.91 and 176 min at a dose of 10 mg/kg, respectively). The AUC increased with nonlinear pharmacokinetics following the dosage increase from 2 to 10 mg/kg in rats, while the pharmacokinetics were not significantly altered in beagle dogs following a dosage increase from 0.5 to 2.5 mg/kg. Of the various tissues tested, ID-6105 was mainly distributed in the lung, spleen, kidney, adrenal gland, and liver after i.v. bolus administration. ID-6105 levels in the lung or kidney 2 h after i.v. bolus administration were comparable to the initial plasma concentration. However, the ID-6105 concentrations in various tissues 48 h after i.v. bolus administration became too small to measure. The cumulative amounts of ID-6105 found in the bile 48 h after the administration of 2 and 10 mg/kg were calculated to be 26.7 and 18.5% of the initial dose, respectively. The corresponding values in the urine 72 h after i.v. administration were 4.33 and 3.07% of the initial dose, suggesting that ID-6105 is mostly excreted in the bile. In conclusion, our observations indicate that ID-6105 was rapidly cleared from the blood and transferred to tissues such as the lung, spleen, kidney, and liver 2 h after i.v. bolus administration. Moreover, the majority of ID-6105 appears to be excreted in the bile by 24 h after i.v. bolus administration.     

间硝苯地平在Beagle犬体内的药代动力学

目的用反相高效液相色谱法研究间硝苯地平(m-nifedipine，m-Nif)在Beagle犬体内的药代动力学特征。方法正交设计优化色谱分离条件，Beagle犬分别iv给予m-Nif 0.288 mg·kg^-1和ig m-Nif 1.152，3.456，10.370 mg·kg^-1。用反相高效液相色谱法分析血浆中原型药物浓度，血浆药物浓度-时间数据用3P97药代动力学软件分析。结果Beagle犬iv m-Nif，其体内过程符合二室模型，T_1/2β为116.8 min；ig给予m-Nif 后在Beagle犬体内的代谢符合一室模型，其中低剂量(1.152 mg·kg^-1)组C_max为20 μg·L^-1， T_1/2(k_e)为147 min；中剂量(3.456 mg·kg^-1)组C_max为36 μg·L^-1，T_1/2(k_e) 为122 min；高剂量(10.37 mg·kg^-1)组C_max为69 μg·L^-1，T_1/2(k_e)为144 min。结论Beagle犬ig和iv m-Nif 后，血浆中药物消除迅速，口服绝对生物利用度较低。     

Oral and intravenous trichloroethylene pharmacokinetics in the rat

The pharmacokinetics of trichloroethylene (TCE) was studied in male Sprague-Dawley rats (300-350 g). TCE was administered intravenously and orally at doses of 5, 10, and 25 mg/kg to nonfasted rats and orally at 10 mg/kg to rats fasted for 8-10 h. The disappearance of TCE from the blood of intravenously dosed animals was best described by a two-compartment open pharmacokinetic model. The volume of the central compartment (Vc) approximated the rats' blood volume (50-70 ml/kg). The volume distribution (V beta) and total body clearance (CLT) decreased with increase in dose. The terminal half-life (t1/2) was about 120 min and was not affected by increases in dose. TCE was rapidly absorbed after oral dosing, with blood concentrations peaking between 6 and 10 min. The oral to intravenous bioavailability of TCE was 60-80% in nonfasted animals. The terminal t1/2 in fasted, orally dosed rats was identical to that when fasted rats were given the same dose intravenously. In fasted rats, bioavailability of an oral dose was greater than 90%, and peak levels in the blood were 2-3 times as high as in nonfasted rats.