Effects of UDP-glucuronosyltransferase (UGT) polymorphisms on the pharmacokinetics of febuxostat in healthy Chinese volunteers

The pharmacokinetics (PKs) of febuxostat varies among individuals, while the main causes are still unknown. We investigated whether the polymorphisms of UGT1A1 and UGT1A3 played an important role in the disposition of the drug after oral administration of febuxostat tablet in Chinese subjects. A total of 42 healthy subjects were from two previous independent clinical bioequivalence (BE) trials of febuxostat, in which the same reference formulation (ULORIC^® tablet, 80 mg) was taken, and thus the PK data were combined for the evaluation of pharmacogenomic effect on febuxostat PKs. Our study clearly indicated that the area under the plasma concentration-time curve (AUC) in the heterozygote and homozygote of UGT1A1*6 (c.211G > A, rs4148323) was significantly higher than that in the wild-type. Meanwhile, the clearance (CL/F) exhibited a significant reduction by 22.2%. Interestingly, UGT1A1*28, in perfect linkage disequilibrium (LD) with UGT1A3*2a, significantly increased its clearance. These results indicate that UGT1A1*6 was an important factor influencing the drug disposition, thus providing a probable explanation for interindividual variation of febuxostat PKs in Chinese subjects. In addition, by considering of the different allele distribution of UGT1A1*6 and *28 in Eastern and Western populations, these findings might further interpret the ethnic difference of febuxostat PKs.     

Non-linearities in the pharmacokinetics of di-(2-ethylhexyl) phthalate and metabolites in male rats

The disposition of the plasticizer di-(2-ethylhexyl) phthalate (DEHP) and four of its major metabolites was studied in male rats given single infusions of a DEHP emulsion in doses of 5, 50 or 500 mg DEHP/kg body weight. Plasma concentrations of DEHP and metabolites were followed for 24 h after the start of the infusion. The kinetics of the primary metabolite mono-(2-ethylhexyl) phthalate (MEHP) was studied separately.The concentrations of DEHP in plasma were at all times considerably higher than those of MEHP, and the concentrations of MEHP were much higher than those of the other investigated metabolites. In animals given 500 mg DEHP/kg, the areas under the plasma concentration-time curves (AUCs) of the other investigated metabolites were at most 15% of that of MEHP. Parallel decreases in the plasma concentrations of DEHP, MEHP and the and (-1) oxidized metabolites indicated that the elimination of DEHP was the rate-limiting step in the disposition of the metabolites. This was partly supported by the observation that the clearance of MEHP was higher than that of DEHP. Nonlinear increases in the AUCs of DEHP and MEHP indicated saturation in the formation as well as the elimination of the potentially toxic metabolite MEHP.     

Intrapulmonary pharmacokinetics and pharmacodynamics of meropenem

The objective of this study was to determine the plasma and intrapulmonary pharmacokinetic parameters of intravenously administered meropenem in healthy volunteers. Four doses of 0.5 g, 1.0 g or 2.0 g meropenem were administered intravenously to 20, 20 and 8 healthy adult subjects, respectively. Standardised bronchoscopy and timed bronchoalveolar lavage (BAL) were performed following administration of the last dose. Blood was obtained for drug assay prior to drug administration and at the time of BAL. Meropenem was measured in plasma, BAL fluid and alveolar cells (ACs) using a combined high pressure liquid chromatographic–mass spectrometric technique. Plasma, epithelial lining fluid (ELF) and AC pharmacokinetics were derived using non-compartmental methods. C_max/MIC₉₀ (where C_max is the maximum plasma concentration and MIC₉₀ is the minimum inhibitory concentration required to inhibit 90% of the pathogen), AUC/MIC₉₀ (where AUC is the area under the curve for the mean concentration–time data), intrapulmonary drug exposure ratios and percent time above MIC₉₀ during the dosing interval (%T > MIC₉₀) were calculated for common respiratory pathogens with MIC₉₀ values of 0.12–4 μg/mL. In the 0.5 g dose group, the C_max (mean ± S.D.), AUC_0–8 h and half-life for plasma were, respectively, 25.8 ± 5.8 μg/mL, 28.57 μg h/mL and 0.77 h; for ELF the values were 5.3 ± 2.5 μg/mL, 12.27 μg h/mL and 1.51 h; and for ACs the values were 1.0 ± 0.5 μg/mL, 4.30 μg h/mL and 2.61 h. In the 1.0 g dose group, the C_max, AUC_0–8 h and half-life for plasma were, respectively, 53.5 ± 19.7 μg/mL, 55.49 μg h/mL and 1.31 h; for ELF the values were 7.7 ± 3.1 μg/mL, 15.34 μg h/mL and 0.95 h; and for ACs the values were 5.0 ± 3.4 μg/mL, 14.07 μg h/mL and 2.17 h. In the 2.0 g dose group, the C_max, AUC_0–8 h and half-life for plasma were, respectively 131.7 ± 18.2 μg/mL, 156.7 μg h/mL and 0.89 h. The time above MIC in plasma ranged between 28% and 78% for the 0.5 g dose and between 45% and 100% for the 1.0 g and 2.0 g doses. In ELF, the time above MIC ranged from 18% to 100% for the 0.5 g dose and from 25% to 88% for the 1.0 g dose. In ACs, the time above MIC ranged from 0% to 100% for the 0.5 g dose and from 24% to 100% for the 1.0 g dose. Time above MIC in ELF and ACs for the 2.0 g dose was not calculated because of sample degradation. The prolonged T > MIC₉₀ and high intrapulmonary drug concentrations following every 8 h administration of 0.5–2.0 g doses of meropenem are favourable for the treatment of common respiratory pathogens.     

松果菊苷药动/药效研究进展与思考

本文综述了近年来松果菊苷（ECH）在抗衰老、提高记忆力与神经保护、抗肿瘤、保护肝脏及免疫调节等方面的药理作用研究进展,探讨了其可能的作用机制。此外,还对ECH的吸收和代谢等药代动力学最新研究进展进行总结,并将其药效学特征与药代动力学行为进行联系与比较,指出了ECH药效学和药代动力学之间存在的表面矛盾,并就如何解释这些矛盾进行了探讨。在此基础上,提出天然来源的创新药物通常具有系统前广泛代谢的特点,发挥整体药效作用的可能是其活性代谢产物;应针对中药I类新药的这些特点,加强系统前代谢转化研究;并制订科学合理的临床前药物代谢动力学技术指导原则,用以指导具有类似特点的中药I类新药的研究。     

尼莫地平片相对生物利用度及药物动力学研究

本实验采用反相高效液相色谱法测定10名志愿受试者单剂量口服120mg尼莫地平片供试品与标准参比制剂后,尼莫地平血药浓度变化情况,经3p87药动学程序处理,药时曲线下面积分别是:82.51±28.73ng/ml×h与82.92±30.93ng/ml×h,达峰时间分别为:1.75±0.26h与1.70±0.26h,峰浓度分别是:28.84±9.05ng/ml与29.05±8.69ng/ml. 配对t检验与双单侧t检验结果表明:二者药时曲线下面积、峰浓度及达峰时间均无显著性差异,尼莫地平片供试品与标准参比制剂为生物等效制剂.尼莫地平片供试品的相对生物利用度为:100.70%±7.44%.     

Sex-differences in the disposition of substituted benzamides: pharmacokinetics of a gastroprokinetic agent (4-amino-5-chloro-2-[2- (methylsulfinyl) ethoxy]-N-[2-(diethylamino)ethyl] benzamide hydrochloride) (ML-1035) in male and female New Zealand white rabbits.

The disposition of 4-amino-5-chloro-2-[2-(methylsulfinyl)ethoxy]-N- [2-(diethylamino)ethyl] benzamide hydrochloride (ML-1035) following intravenous (10 mg kg-1) and oral (200 mg kg-1) dosing was investigated in male and female New Zealand white rabbits. After intravenous dosing ML-1035 was eliminated with a half-life of 1.45 +/- 0.49 h in males and 0.79 +/- 0.08 h in females. Volume of distribution at steady-state was 2.08 +/- 0.98 l kg-1 in males and 9.11 +/- 5.86 l kg-1 in females. Clearance averaged 2.99 +/- 1.11 l h-1 kg-1 in males and 16.73 +/- 7.29 l h-1 kg-1 in females. All pharmacokinetic parameters were significantly different between males and females (p < 0.05). Absolute bioavailability after oral administration was 7.35 per cent for males and 12.31 per cent for females, suggesting that ML-1035 undergoes significant first-pass elimination. Plasma area under the curve for the metabolites of ML-1035 after both oral and intravenous administration were also different between the two sexes. These data suggest that the disposition of ML-1035 shows significant differences between male and female rabbits.     

Physiological pharmacokinetics and pharmacodynamics of (+/-)-verapamil in female rats

Tissue distribution and pharmacodynamics of verapamil were evaluated during steady state intravenous (i.v.) infusion and after single dose intraperitoneal (i.p.) drug administration to female Sprague-Dawley rats. In one group of rats, verapamil was infused to a steady state concentration at which time animals were killed. Verapamil-induced decreases in mean arterial pressure (MAP) were monitored during infusion and correlated with concomitantly obtained plasma verapamil concentrations. Tissue (lung, liver, renal medulla, renal cortex, cardiac muscle, skeletal muscle, perirenal fat, brain stem, cerebral cortex, and cerebellum) and plasma samples were obtained immediately after animals were killed and verapamil and norverapamil concentrations determined. Another group of rats, after receiving i.p. verapamil, were killed at 1, 3, 5, 19, and 24 h. Elimination from each tissue evaluated was described by a first order process. Elimination half-life of verapamil was similar among plasma and tissues evaluated (1.5 to 2.2 h). The per cent verapamil not bound to plasma proteins was concentration-independent and similar between rats receiving i.p. (mean +/- S.D.) (2.28 +/- 0.72 per cent) and i.v. (2.08 +/- 0.03 per cent) verapamil. MAP and verapamil concentration in plasma (r = 0.75; p less than 0.01) and cardiac muscle (r = -0.82; p less than 0.01) were inversely correlated in a highly significant fashion during both i.v. and i.p. drug administrations. The tissue-to-plasma distribution ratio for verapamil and norverapamil was similar among animals receiving i.p. verapamil at all points of sampling, suggesting distribution equilibrium had been achieved. After steady state i.v. infusion, both verapamil and norverapamil tissue: plasma concentration ratios were greater than after i.p. administration. Higher tissue: plasma verapamil concentration ratios after i.v. administration than after i.p. administration suggest either only a pseudoequilibrium is attained after i.p. administration or that determinants of tissue distribution of racemic verapamil differ with different routes of drug administration. In these studies, MAP provided a reasonable pharmacodynamic marker for verapamil tissue and plasma concentrations.     

基于第三代头孢菌素药动学相关研究的可视化分析

目的 梳理Web of Science数据库中关于第三代头孢菌素药动学(Pharmacokinetics, PK)研究,通过文献计量学和可视化分析方法,评价该领域的研究方向、研究热点以及发展趋势,为今后研究提供经验和借鉴。方法 使用Web of Science数据库进行检索,检索式为“Theme=("Third-Generation Cephalosporin"OR Cefoperazone) OR Ceftazidime) OR Cefixime) OR Cefodizime) OR Ceftriaxone) OR Cefotaxime) AND (pharmacokinetics OR PK OR"Population pharmacokinetics")”,检索时间为2009-2020年。利用VOS-viewer软件进行合著分析(作者、机构、国家)、共现分析和共引分析;通过GraphPadPrism8软件进行第三代头孢菌素药动学研究的趋势分析。结果 对纳入的818篇文献进行可视化分析,结果显示发文量呈现逐年上涨趋势,其中发文量最多的国家是美国(288篇,35.21%),最多的期刊...     

Clinical pharmacokinetics of pancuronium bromide

Summary Plasma concentrations of pancuronium bromide have been studied in seven surgical patients following a 6 mg intravenous bolus injection of the drug for neuromuscular blockade. Concurrently, evoked muscle twitch response was monitored for each patient as a measure of the pharmacodynamic effect of the drug. The plasma decay curve for pancuronium was found to be biphasic and after rigorous statistical analysis the data were interpreted according to a 2-compartment open model. The half-life of the -phase varied between 89.5 and 161.5 min. The apparent volume of distribution of the central compartment ranged from 62.9 to 145.5 ml/kg and the plasma clearance from 57.6 to 187.3 ml/min. At the first sign of recovery from neuro-muscular blockade the mean pancuronium plasma level was found to be 0.218 mcg/ml. The mean duration of action as measured from time of onset of paralysis to 20% recovery was 83.4 min with the plasma level at 20% being 0.169 mcg/ml corresponding to 45.4% of dose remaining to be eliminated from the body.     

Single-dose study to compare the pharmacokinetics of HFA flunisolide and CFC flunisolide

The hydrofluoroalkane (HFA) formulation of the inhaled corticosteroid flunisolide is a modification of the original chlorofluorocarbon (CFC) formulation. HFA flunisolide replaces CFC with an HFA propellant and uses a built-in spacer in its pressurized metered-dose inhaler. The average HFA flunisolide particle size is 1.2 microm compared with 3.8 microm for the CFC formulation. The smaller particle size improves lung targeting, allowing a reduction in the HFA flunisolide dose relative to CFC flunisolide while maintaining comparable efficacy. In a study of 12 healthy men, pharmacokinetic parameters were determined after single doses of 1000 microg CFC flunisolide delivered without a spacer, 340 microg HFA flunisolide delivered through a spacer, and 516 microg HFA flunisolide delivered without a spacer. A standard noncompartmental analysis of the concentration data was performed and mean (+/- S.D.) pharmacokinetic values were reported. Peak plasma concentrations (observed C(max)) were similar for the three treatments. Area under the curve up to the time corresponding to the last measurable concentration (AUC(0)(-)(tlast)) was similar for the CFC and HFA flunisolide, plus spacer groups (4.4 +/- 1.6 ng x h/mL and 5.0+/- 4.2 ng x h/mL, respectively); however, AUC(0)(-)(tlast) for the HFA flunisolide without spacer group was comparatively lower than for the CFC group (3.5 +/- 1.6 ng x h/mL). Observed C(max) and AUC(0)(-)(tlast) for 6 beta-OH flunisolide, the first-pass metabolite of flunisolide and an indicator of oropharyngeal deposition, were significantly higher in the CFC flunisolide group than in either HFA flunisolide group.     

Toxicology and pharmacokinetics of piperaquine in mice

Pharmacokinetic and toxicological data for piperaquine (PQ) - a bisquinoline antimalarial drug - are limited, despite strong evidence of clinical efficacy. Our aim was to conduct a detailed toxicological investigation of PQ in Swiss mice. The study comprised three phases: (i) oral PQ phosphate (PQP) at doses ranging from 0 to 600 mg/(kg day) for 5 days. Pathology tests included haematological and biochemical indices, and histopathology of the liver, heart and kidneys. (ii) PQP doses of 0-300 mg/(kg day) for 12 days and pathology tests as described. (iii) Pharmacokinetic parameters determined from mice given 100mg/(kg day) PQP for 5 days. Blood was harvested from mice over 56 days and plasma analysed by HPLC. Mice given low doses of PQ had stable, normal body and organ weights. Weight loss was observed in mice given high doses and was accompanied by increased liver and kidney weights. Principal haematological effects were modest fluctuations in total white cells and neutrophils; biochemical effects were elevated ALT and low albumin in high-dose groups. Liver histopathology revealed minor cytoplasmic and inflammatory effects. PQ treatment did not affect heart muscle but minor renal changes were observed at high doses. Pharmacokinetic parameters were consistent with previous studies: t1/2, CL and V were 16 days, 1.36 L/(h kg) and 756 L/kg, respectively. PQ may cause minor hepatotoxicity and renal tubular cell damage, and adversely affect selected haematological indices, as demonstrated at cumulative doses approximately 50 times those recommended in humans. Significant effects in humans will likely be infrequent and dose-related.     

前药的药代动力学研究进展

前药是自身无活性,在体内经生物转化后释放出有药效活性的代谢物或原药的化合物。前药设计已成为改善药物的一些不良性质如水溶性低、生物利用度差、半衰期太短及缺乏理想的靶向性等的一种重要手段。然而如何从药物代谢动力学角度评价前药尚缺乏统一的标准。本文对近年来前药的药代动力学研究状况进行了概括总结,并提出如何从吸收、分布、代谢和排泄角度对前药的药代动力学性质进行全面评价。     

Sibutramine pharmacokinetics in young and elderly healthy subjects

Objective: To investigate the pharmacokinetics of the pharmacologically active metabolites of sibutramine (metabolites 1 and 2) in healthy young and elderly volunteers following a single oral dose of sibutramine. Methods: This was an open, parallel-group study completed by 12 young (six male, six female; mean age 24.0 years) and 12 elderly (six male, six female; mean age 70.3 years) healthy volunteers. Blood samples were taken at intervals up to 48 h post-dose. Plasma concentrations of metabolites were determined using HPLC-MS. Model-independent pharmacokinetic parameters of the two metabolites were compared for the two age groups. Results: The similarity of the plasma profiles of the two desmethyl metabolites showed that despite the possibility of reduced hepatic function due to age, the rate and extent of formation of these was the same in both young and elderly, i.e. sibutramine metabolism was not impaired in elderly subjects. There were also no significant differences in elimination of metabolite 2 between groups, although the elderly group showed a slight trend for a reduction in k_el. Conclusions: The pharmacokinetics of the two pharmacologically active metabolites of sibutramine (metabolites 1 and 2) were not significantly different between the young and elderly groups in this study. Based on this information, a similar dosing regimen would be appropriate for both the young and elderly. Received: 8 June 1998 / Accepted in revised form: 18 September 1998     

Metabolism and pharmacokinetics of S-(N,N-diethyldithiocarbamoyl)-N-acetyl-L-cysteine in rats

The metabolism and pharmacokinetics of a mixed disulfide S-(N,N-diethyldithiocarbamoyl)-N-acetyl-L-cysteine (AC-DDTC) were studied in rats. Two metabolites of AC-DDTC following i.v. and p.o. administration were identified in plasma and liver by HPLC and GC, namely N,N-diethyldithiocarbamate (DDTC) and the methyl ester of DDTC (Me-DDTC). AC-DDTC was very unstable in vivo and could not be detected neither in plasma nor in urine. Pharmacokinetic parameters of DDTC following intravenous administration of AC-DDTC (20 mg/kg) were calculated. DDTC has a low affinity to rat tissue and the total body clearance was 9.0 +/- 3.4 ml/min/kg. The mean residence time (MRT) was 111.5 +/- 16.3 min. After oral administration of 20 mg/kg AC-DDTC, maximal plasma concentration (Cmax) was 3.8 +/- 0.2 nmol/ml and the bioavailability was 7.04%. Cmax for DDTC at a dose of 120 mg/kg AC-DDTC was 40.1 +/- 2.2 nmol/ml. MRT was 47.1 +/- 2.8 min at a dose of 20 mg/kg and 110.5 +/- 6.0 min at 120 mg/kg.     

纳米药物的药动学研究概况分析

纳米药物是一种具有同生物膜性质类似的磷脂双分子层结构载体的药物,与传统给药形式的药物以游离的分子态被吸收相比,纳米药物有大部分量以纳米聚集态形式被吸收,同时兼有分子态吸收,从而具有不同的体内过程,并产生特殊的生物活性。本文对近年来纳米药物的药动学研究进展进行了综述。     

Modelling the pharmacokinetics and pharmacodynamics of trimazosin

The pharmacokinetics and pharmacodynamics of trimazosin are described following both intravenous and oral administration to 6 normotensive, male volunteers. The IV and oral drug and metabolite (1-hydroxytrimazosin) concentration data are fitted simultaneously to the same pharmacokinetic model. The pharmacodynamic response, change in systolic blood pressure following 5 min in the erect posture, is described using several possible models. The most efficient is one which attributes the response to both the parent drug and its principal metabolite. The response following oral administration is also consistent with this model. It appears that the reduction in blood pressure following administration of trimazosin at steady state may be governed by the concentration of metabolite.     

手性药物代谢动力学的立体选择性

手性是生物体系的一个基本特征。手性大分子物质,如酶、载体、受体、血浆蛋白和多糖等构成了生物体的手性内环境。在体内,手性药物对映体与生物大分子间相互识别、相互作用的立体选择性导致了手性药物在药代动力学方面的立体选择性,其主要表现在手性药物的吸收、分布、代谢和排泄四个过程的差异。     

HPLC-UV法测定大鼠体内S-腺苷蛋氨酸浓度及其药动学研究

目的：建立HPLC-UV法测定大鼠血浆中S-腺苷蛋氨酸（S-Adenosylmethionine,SAMe）浓度,并用此法研究静脉给药后的大鼠体内药代动力学特征。方法：色谱柱：大连依利特KromasilC18柱（4.6mm×200mm,5μm）,流动相：甲醇∶0.3%三氟乙酸溶液（含1%磷酸二氢钠盐）=2∶98,等浓度洗脱,紫外检测波长：260nm,流速：0.6mL/min,柱温：30℃。大鼠（n=6）经静脉给予140mg/kg SAMe并测定血浆药物浓度,采用DAS 2.0软件进行药动分析。结果：SAMe能完全分离,线性范围：10～2000μg/mL,回归方程为Y=30241 X＋256204,r=0.9991,日内精密度分别为2.6%,3.6%,3.9%;日间精密度分别为6.3%,4.9%,7.9%;回收率分别为107%,101%,98.3%。静脉给予140mg/kg SAMe药动学参数,血浆药物浓度-时间曲线下面积AUC（0-t）为（569.52±174.87）mg·L-1·h,半衰期（t1/2）为（2.03±0.96）h,清除率（CL）为（0.21±0.13）L·h-1·kg-1,表观分布容积（Vd）为（0.53±0.31）L/kg。结论：本实验方法专属性好,灵敏度高,可靠性强,可用于SAMe药动学分析。     

ICI 141,292 (epanolol) —pharmacokinetics after single and repeated oral administration in the elderly with moderate renal impairment

Summary The pharmacokinetics of ICI 141,292 (epanolol) were studied over 3 days after a single oral 200 mg dose and then over 24 h after 12 consecutive daily oral 200 mg doses in 16 elderly subjects (aged 65 to 94 years) with moderate renal impairment (mean creatinine clearance 33.2 ml · min⁻¹). There was wide inter-individual variability in peak plasma ICI 141,292 concentrations (C_max) but no significant difference was found between mean C_max after a single dose (44.3 ng. ml⁻¹) and after 12 doses (37.4 ng. ml⁻¹). The mean observed time to peak plasma ICI 141,292 concentration (t_max) after a single dose (1.61 h) did not differ significantly from that after 12 doses (1.75 h). On several occasions an analytically significant second peak in ICI 141,292 plasma concentration was observed. Following the peak(s), the plasma concentrations declined biphasically and a mean terminal phase plasma half-life (t11/2) of 28.3 (range 10.2–84.8) h was calculated after a single dose. The inter-individual variability in the area under the plasma concentration-time curve to 24 h AUC (0-24) was 54 fold but there was no significant difference between AUC (0-24) after a single dose (mean 226.0 rig·h·m1⁻¹) and AUC (0-24) after 12 consecutive doses of ICI 141,292 (mean 232.4 ng·h·ml⁻¹). The results show that consecutive daily administration of 12 oral doses of IC1 141,292 (200 mg) does not result in significant accumulation of drug in elderly subjects with moderate renal impairment.