Pharmacokinetics of aprepitant after single and multiple oral doses in healthy volunteers

Aprepitant is the first NK1 receptor antagonist approved for use with corticosteroids and 5HT3 receptor antagonists to prevent chemotherapy-induced nausea and vomiting (CINV). The effective dose to prevent CINV is a 125-mg capsule on day 1 followed by an 80-mg capsule on days 2 and 3. Study 1 evaluated the bioavailability of the capsules and estimated the effect of food. The mean (95% confidence interval [CI]) bioavailabilities of 125-mg and 80-mg final market composition (FMC) capsules, as assessed by simultaneous administration of stable isotope-labeled intravenous (i.v.) aprepitant (2 mg) and FMC capsules, were 0.59 (0.53, 0.65) and 0.67 (0.62, 0.73), respectively. The geometric mean (90% CI) area under the plasma concentration time curve (AUC) ratios (fed/fasted) were 1.2 (1.10, 1.30) and 1.09 (1.00, 1.18) for the 125-mg and 80-mg capsule, respectively, demonstrating that aprepitant can be administered independently of food. Study 2 defined the pharmacokinetics of aprepitant administered following the 3-day regimen recommended to prevent CINV (125 mg/80 mg/80 mg). Consistent daily plasma exposures of aprepitant were obtained following this regimen, which was generally well tolerated.     

Pharmacokinetics of nilvadipine in healthy volunteers

The pharmacokinetics of nilvadipine, a new antihypertensive and antianginal drug, were examined in healthy male volunteers. In a Latin square, three-way crossover design with a one-day run-in period, six subjects in three groups of two each were given single 2-, 4-, or 6-mg oral doses of nilvadipine after overnight fasting. Nilvadipine plasma concentrations up to 32 hours after drug treatment were determined by capillary column gas chromatography-negative-ion chemical ionization mass spectrometry (detection limit, 0.01 ng/mL). Nilvadipine urinary concentrations were determined by capillary column gas chromatography with electron capture detector (detection limit, 0.5 ng/mL). Nilvadipine plasma concentrations declined in a bi- or triexponential pattern after reaching the maximum plasma concentrations. The mean +/- standard deviation maximum plasma concentrations of 1.48 +/- 0.47, 3.48 +/- 0.53, and 6.69 +/- 1.54 ng/mL were attained from 1.08 to 1.50 hours after doses of 2, 4, and 6 mg, respectively. The elimination half-life was dose-independent and averaged 11.0 +/- 2.3 hours. The area under the plasma concentration-time curve increased in proportion to the dose. Nilvadipine was not detected in the urine. The pharmacokinetics of nilvadipine were generally linear over the dosage range studied. Besides the above model-independent pharmacokinetic parameters, model-dependent parameters were also obtained by curve-fitting the plasma data to a bi- or triexponential equation with zero-order absorption. Nilvadipine decreased blood pressure slightly and in a dose-dependent fashion.     

Pharmacokinetics of deramciclane and N-desmethylderamciclane after single and repeated oral doses in healthy volunteers

OBJECTIVE: To study the pharmacokinetics and accumulation of deramciclane and its metabolite N-desmethylderamciclane after 60 mg twice daily doses for 4 weeks. METHODS: Sixteen healthy male subjects, age range of 20-29 years, participated in this randomized, double-blind, parallel-group, placebo-controlled study. Ten subjects first received a single 60 mg dose of deramciclane followed by 60 mg deramciclane b.i.d. between days 4 and 31. Six subjects received matching placebo in a similar manner. Pharmacokinetics of deramciclane and N-desmethylderamciclane were determined on days 1, 10, 17, 24 and 31. Plasma prolactin concentrations were measured before drug administration and 4 hours after on the same days. Safety was monitored using repeat laboratory determinations and ECG recordings. RESULTS: The mean (SD) AUC(0-infinity) of deramciclane was 1,251 (385) ng x h/ml after the first dose. The AUC(tau) calculated for the dosing interval was significantly higher at week 1 (p = 0.048) than the AUC(0-infinity) after the first dose but thereafter there was no further accumulation of deramciclane. The mean accumulation indices at weeks 1, 2, 3 and 4 varied between 2.3 and 2.7 with no tendency to increase over time. The mean apparent elimination half-life of deramciclane was 24.9 (3.5) hours after the first dose and 29.3 (9.3) hours after 4-week repeated dosing; this difference was not statistically significant. The accumulation index of N-desmethylderamciclane increased from week 1 to week 2 but remained stable thereafter. The treatment was well tolerated. Plasma prolactin levels were not influenced by deramciclane administration. CONCLUSIONS: Deramciclane administration, 60 mg twice daily for 4 weeks to healthy male volunteers, is well tolerated, and there is no evidence of continuous accumulation of the drug during maintenance treatment. Deramciclane at a dose of 60 mg b.i.d. does not antagonize dopamine receptors to a significant degree.     

Pharmacokinetics of moxonidine after single and repeated daily doses in healthy volunteers

The pharmacokinetics of the centrally acting alpha-2 agonist moxonidine were investigated in 12 healthy male subjects after single and repeated oral doses (q12h for five days) of moxonidine 0.2 mg. Plasma concentration-time data followed the general characteristics of a one-compartment model with first-order absorption. Peak plasma concentrations of 1.29 +/- 0.32 ng/mL were achieved 0.74 +/- 0.35 hours after ingestion of a 0.2-mg tablet. The terminal half-life of elimination was 2.12 +/- 0.58 hours. The oral clearance (CL/F) amounted to 830 +/- 171 mL/min with renal elimination being the major route of elimination. No significant differences in pharmacokinetic parameters could be observed following repeated dosing over five days.     

Pharmacokinetics of alfuzosin after single oral administration to healthy volunteers, of three different doses.

The aim of this study was to assess the linearity of pharmacokinetic of alfuzosin, administered by oral route, at the doses of 1, 2.5, and 5 mg to 12 young healthy volunteers. The pharmacokinetic parameters (tmax, Cmax, AUC, t1/2 beta) obtained from plasma alfuzosin concentrations after administration of the three doses show that pharmacokinetics of alfuzosin is linear in the range of doses 1-5 mg. Mean pharmacokinetic parameters of alfuzosin observed after 1, 2.5, and 5 mg were, respectively: tmax (h) 1.5 +/- 0.3, 1.1 +/- 0.2, 1.3 +/- 0.1; Cmax (ng ml-1) 2.6 +/- 0.3, 9.4 +/- 1.2, 13.5 +/- 1.0; AUC (ng ml-1 h) 17.7 +/- 2.9, 51.7 +/- 7.1, 99.0 +/- 14.1; t1/2 (h) 3.7 +/- 0.4, 3.9 +/- 0.2, 3.8 +/- 0.3. Cmax (corrected by the dose) obtained after 2.5 mg was significantly higher than those obtained after 1 and 5 mg. This difference seems to be due principally to the intraindividual variability. The absence of statistically significant difference on individual values of AUC corrected by the administered dose, supports the linearity of the pharmacokinetics of alfuzosin in the range of doses between 1 and 5 mg. Some postural hypotension, clinical criterion, was observed with a frequency increasing with the dose in these healthy subjects: 0 volunteers of 12 after 1 mg, 3 volunteers of 12 after 2.5 mg and 4 volunteers of 12 after 5 mg.     

Pharmacokinetics and tolerance of romazarit after oral administration of ascending single doses to healthy human volunteers

Forty-four healthy male volunteers participated in an investigation of the pharmacokinetics and tolerance of single oral doses of romazarit, a potential disease-modifying antirheumatic drug. The study design involved single oral doses in ascending sequence from 40 to 1500 mg. At each dosage 9 volunteers were studied, of whom 6 received romazarit and 3 received placebo capsules in a double-blind manner. Tolerance was assessed before and after each of the 57 romazarit and 27 placebo doses. Plasma and urinary concentrations of romazarit were measured by HPLC with UV detection. Model-independent pharmacokinetic analyses showed that romazarit was rapidly and extensively absorbed in a dose-proportional manner. Urinary recovery of drug related material was about 70% of the dose and almost all in the form of labile metabolites (probably acyl glucuronides). Clearance was faster (greater than 3 l/h) at doses below 700 mg, than in the range 700-1500 mg (1.7 l/h). It is suggested that two or more clearance mechanisms are present. One of these mechanisms is saturable and may involve a reversible ester glucuronide formation coupled with saturable tubular secretion of glucuronides. Romazarit was well tolerated in these healthy volunteers. There were two reports of stomach pain, one associated with vomiting. Changes in laboratory safety test results and in measurements of vital signs were similar in frequency and magnitude after romazarit and after placebo doses.     

Pharmacokinetics of N-desmethyldiazepam in healthy volunteers after single daily doses of dipotassium chlorazepate

Dipotassium chlorazepate was administered to 12 healthy volunteers (8 males and 4 females), aged 22–38 years, as a single daily dose of 20 mg for 14 days. Plasma concentrations of N-desmethyldiazepam were monitored with a gas-chromatographic method during the medication period and for 5 days after withdrawal of the drug. The plasma half-life (t _1/2), the elimination coefficient (K ), the concentration ( ), and the apparent volume of distribution (V ) were calculated at steady state, and the mean values±SEM were 53±6 h, 0.0147±0.0013 h^-1, 884±73 ng/ml, and 1.13±0.08 l/kg, respectively. A moderate interindividual variability was observed regarding these parametes. There was no tendency toward a biexponential elimination. A significant difference in the apparent volume of distribution was found when males and females were compared.     

健康人单次口服不同剂量依地普仑片的药动学

目的研究中国健康志愿者单次口服不同剂量依地普仑草酸盐片的体内药动学特点.方法32例受试者单次空腹口服依地普仑草酸盐片,剂量分别为10(n=10),20(n=12),30mg(n=10).用HPLC荧光检测法测定血浆中的依地普仑浓度,用DAS统计软件进行数据处理,计算药动学参数.结果草酸依地普仑片药动学特点符合二房室模型,为线性药动学特点,单次口服依地普仑10,20和30mg的主要药动学参数是Cmax分别为(20.91±4.94),(40.28±10.13)和(57.66±10.51)μg·L-1;Tmax分别为(3.80±1.23),(4.18±0.98)和(4.00±1.49)h;t1/2分别为(34.08±26.58),(36.02±23.68)和(36.95±11.58)h;AUC0～1,分别为(846.8±466.7),(1437.5±535.5)和(2277.5±506.5)μg·h·L-1,AUC0～∞分别为(975.7±622.4),(1587.1±731.2)和(2496.6±707.4)μg·h·L-1.药动学参数的个体间差异较大,CV%最大值为77.99%.女性受试者和男性受试者的血浆清除率(CL/F)及单位剂量的AUC0～1和AUC0～∞值相似.结论中国健康受试者单次口服不同剂量草酸依地普仑的药动学参数具有线性药动学特点.     

Pharmacokinetics of dipyridamole-beta-cyclodextrin complex in healthy volunteers after single and multiple doses.

Dipyridamole is a well known anti-aggregating agent characterized by poor water solubility as well as scant and variable bioavailability. Recently, the compound was complexed with beta-cyclodextrin forming a molecular encapsulation resulting in better oral absorption and stronger biological activities in animals. In the present study, a randomized double blind cross-over comparison between dipyridamole-beta-cyclodextrin complex (dip-beta-CD) and dipyridamole was performed in 12 healthy subjects after single (75mg) and multiple oral treatments (75mg TID). Dip-beta-CD showed better bioavailability and less interindividual variability than dipyridamole either after single or multiple doses. In particular, dip-beta-CD had a greater AUC and Cmax, and a smaller Tmax even at the steady state. In addition, 100% of the subjects receiving a single dose of dip-beta-CD, as compared to 66.7% of those treated with dipyridamole, had plasma levels superior to 1 microgram/ml (which is the supposed anti-aggregating threshold level). In contrast, 0 and 33.03% of the subjects showed plasma levels superior to 2.5 micrograms/ml (which might cause the appearance of side-effects) on the 7th day of the multiple treatment with dip-beta-CD and dipyridamole, respectively. In fact, the subjects presenting higher levels after uncomplexed dipyridamole also complained of headache and/or dizziness on occasion. No adverse side effects were reported for dip-beta-CD.     

Pharmacokinetics of piperaquine after single and multiple oral administrations in healthy volunteers

The aim of this work was to study the pharmacokinetics of piperaquine in healthy volunteers. Healthy volunteers received piperaquine and tablets of Artekin by oral administration. The plasma samples were analyzed for piperaquine by liquid-liquid extraction and determined by HPLC-UV. The results demonstrated that the plasma drug concentration-time curves of single and multiple dose of piperaquine were fitted to a two-compartment open model. The pharmacokinetics parameters of piperaquine alone in a single dose were: t(1/2(beta))=(317.2-/+126.6)h, AUC(0-->infinity)=(44293-/+12636)h x ng/ml, V(d)=(9490.9-/+2161.9)ml/kg, and Cl=(22.83-/+9.83)ml/h/kg. In Artekin in a single dose these parameters were: t(1/2(beta))=(302.8-/+180.7)h, AUC(0-->infinity)=(46419-/+13670)h x ng/ml, V(d)=(10188.6-/+3520.3)ml/kg, and Cl=(25.48-/+10.89)ml/h/kg, while in Artekin in multiple doses they were: t(1/2(beta))=(298.9-/+101.9)h, AUC(0-->infinity)=(227692-/+56294)h x ng/ml, V(d)=(5031.5-/+1097.8)ml/kg, Cl=(11.91-/+3.046)ml/h/kg, respectively. The absorption and distribution of piperaquine were quick while the elimination was quite slow. There were significant differences in the pharmacokinetics parameters of piperaquine in Artekin between a single dose and multiple doses (p<0.001), suggesting that piperaquine might accumulate in vivo and that attention should be given to its possible adverse drug reactions in clinical treatment.     

Pharmacokinetics of diclofenac and five metabolites after single doses in healthy volunteers and after repeated doses in patients

1. The kinetics of diclofenac (I) and five of its metabolites (II-VI) were investigated in three healthy volunteers and in six patients. Compounds I-VI were measured by capillary column gas chromatography in plasma and urine. 2. After a single 100 mg dose of diclofenac sodium to volunteers, the drug was absorbed rapidly and showed peak plasma levels of 10-12 nmol/g. The maximum concentrations of five metabolites were comparatively low (0.36-2.94 nmol/g). The mono- and dihydroxy metabolites (II-V) had apparent terminal half-lives similar to that of I (1-3 h), but the hydroxymethoxy metabolite (VI) had a half-life of about 80 h. Renal elimination of VI within 96 h was about 1% of dose and that of I-VI was 36% (free plus conjugated). 3. Following daily treatment with 2 x 75 mg of an experimental sustained release formulation to patients for 6-10 months, steady-state trough concentrations of I-V in plasma were low (average values: 0.23-0.57 nmol/g). The mean trough concentration of VI was comparatively higher at 3.69 +/- 0.91 nmol/g presumably reflecting its accumulation. Despite this it is unlikely to contribute to the drug's therapeutic activity, since it has been shown in laboratory tests to be devoid of anti-inflammatory activity.     

Pharmacokinetics of fluvoxamine maleate after increasing single oral doses in healthy subjects

The pharmacokinetics of fluvoxamine after single oral administration of 25, 50, and 100 mg fluvoxamine maleate was studied in a three-way cross-over study in 12 healthy male subjects. Fluvoxamine was administered orally in a solution. For doseproportionality, AUC, and C_max-dose relationships were evaluated by linear regression. Plasma concentrations increased in a linear dose-dependent manner in the dose range between 25 and 100 mg; t_1/2 and T_max showed no significant differences among treatments. Fluvoxamine was well tolerated.     

Pharmacokinetics of terlipressin after single i.v. doses to healthy volunteers

The pharmacokinetics of triglycyl-lysine-vasopressin (TGLVP) were studied in healthy male volunteers after single i.v. injections of 5, 10 and 20 micrograms/kg b. wt. The half-life of distribution and elimination was 8 and 50 min, respectively. The volume of distribution was 0.7 l/kg b.wt. and the plasma clearance 9 ml/kg b.wt./min. These values are different from those for arginine-vasopressin and lysine-vasopressin (LVP) but confirm to some extent earlier results on TGLVP. No dose-dependent changes of the pharmacokinetics of TGLVP were evident. The LVP formation after TGLVP is described in principle using a combination of pharmacokinetic and pharmacodynamic data. Therapeutically the results in this study suggest a 4-hour interval between injections.     

单次口服莫达芬尼片在中国健康志愿者的药代动力学

目的研究单次口服莫达芬尼片的药代动力学。方法选择9名健康成年男性受试者分别单次口服100,200,300mg 3个剂量的莫达芬尼片后,用HPLC法测定血中原形药莫达芬尼及代谢产物莫达芬尼酸浓度,用3P97软件进行数据处理,计算药代动力学参数。结果原形药莫达芬尼的药-时曲线符合二房室模型,其主要药代动力学参数的Cmax、AUC0-∞、AUC0-t随剂量加大而增加;t1/2b、tmax、b、CL与给药剂量无关。莫达芬尼片原形药经肾排泄较少,48h经肾累积排泄率分别为(4.44±4.28)%,(3.35±2.20)%和(2.86±1.39)%。主要代谢产物莫达芬尼酸药-时曲线符合二房室模型,48h莫达芬尼酸经肾累积排泄率分别为(33.51±18.90)%,(32.36±19.92)%和(22.88±6.89)%。结论莫达芬尼在100～300mg内,呈线性动力学特征而无饱和性,其消除过程是经肝脏代谢,代谢产物为莫达芬尼酸,代谢产物主要经肾排泄。     

单次和连续口服艾司西酞普兰在中国健康志愿者的药代动力学

目的 研究中国健康志愿者单次和连续口服艾司西酞普兰(抗抑郁药)的体内药代动力学特点.方法 12名健康受试者在第1、8～14天,每日1次空腹口服艾司西酞普兰20 mg;第1、14天服药后不同时间点,以及第12～14天每13服药前,取肘静脉血肝素抗凝,用高效液相色谱-荧光检测法测定血浆中的艾司两酞普兰浓度,用DAS软件计算药代动力学参数.结果 艾司西酞普兰的药代动力学特点符合二房室模型,平均t1/2为41.1 h;Cav为(76.4±26.8)μg·L-1;AUCss为(1832.4±642.4)μg·h·L-1;AUC0-∞和AUC0-∞分别为(4765.9±2171.0)和(5385.6±2851.2)μg·h·L-1;tmax为(3.2±1.3)h;t1/2为(41.1±17.7)h;CL为5.0 L·h-1;AUC的平均累积常数RAUC为(1.2±0.3).结论 艾司西酞普兰连续服药7天可以达稳态,体内无蓄积.     

甲磺酸加替沙星片健康人单剂口服药代动力学

目的研究健康人口服单剂甲磺酸加替沙星片后药代动力学特征,为该药II期临床试验提供依据。方法采用3剂量3周期拉丁方实验设计。9名健康受试者单剂口服甲磺酸加替沙星片100、200、300mg,HPLC法测其血清、尿药物浓度。结果受试者口服甲磺酸加替沙星片后,人体耐受良好,体内过程符合二室开放模型。主要药代动力学参数与给药剂量呈线性关系,tmax为0.5～0.7h,Cmax分别为1.42、2.42、3.25μg/ml,AUC0-∞分别为11.33、21.85、32.32μg·h/ml,V/Fc值为50～80L,t1/2β为8～9h,72h尿药累积回收率约为63.5%。结论甲磺酸加替沙星片口服吸收良好,血峰浓度高,组织分布广,消除半衰期长。200mg每日一次口服用于治疗敏感菌感染。     

单次口服阿奇霉素片在中国健康志愿者的药代动力学

目的研究阿奇霉素(大环内酯类抗生素)在中国健康人体的药代动力学。方法 10名健康志愿者单剂量口服阿奇霉素500 mg后,高效液相色谱-紫外检测法测定血清药物浓度;用AIC法结合F检验判别房室模型, DAS程序计算药代动力学参数。结果主要的药代动力学参数:Ka为(0．87 ±0．27)h-1,t1／2β为(39．66±10．85)h,tmax为(2．60±0．52)h,Cmax为(451．19 ±67．72)μg·L-1,CL／F为(0．56±0．13)L·(h·kg)-1,AUC0-144和 AUC0-∞分别为(13．68±2．92)mg·h·L-1和(13．71±2．91)mg·h·L-1。结论最佳房室模型为二室模型。     

Pharmacokinetics of licarbazepine in healthy volunteers: single and multiple oral doses and effect of food

Two studies characterized single- and multiple-dose pharmacokinetics of licarbazepine immediate-release tablets and food effects on single-dose pharmacokinetics. In 1 study, 12 volunteers received 500 mg licarbazepine on day 1, 500 mg bid on days 3 to 6, and 500 mg on day 7. In the second study, 12 subjects received one 500-mg licarbazepine dose under fasted and fed conditions. After multiple dosing, geometric mean (%CV) Cmax ss, Cmin ss, and AUCtau were 77.6 micromol/L (18), 45.3 micromol/L (25), and 747 h.mol/L (19), respectively, with a tmax of 2 hours. Mean half-lives were 9.3 and 11.3 hours for single and multiple dosing, respectively. Food had no clinically significant effect on single-dose pharmacokinetics. Half-life ( approximately 10 hours) and low intersubject variability in main pharmacokinetic parameters were similar under fasted and fed conditions. Median tmax increased from 1.5 to 2.5 hours with food. Licarbazepine is well tolerated and has predictable pharmacokinetics.     

Pharmacokinetics and safety of single oral doses of sirolimus (rapamycin) in healthy male volunteers

A phase I study was conducted to determine the pharmacokinetics, safety, and tolerability of sirolimus, a new immunosuppressive drug, in 45 healthy men between 19 and 36 years of age. Nine subjects in each group were randomly assigned to receive single oral doses of either sirolimus (n = 6) or placebo (n = 3) in group I (0.3 mg/m2), group II (1 mg/m2), group III (3 mg/m2), group IV (5 mg/m2) and group V (8 mg/m2). No serious adverse events occurred during the study. Twenty-eight of the 45 volunteers (62%) reported an adverse event; 19 of 30 (63%) were in the sirolimus group and 9 of 15 (60%) were in the placebo group (ns). Asthenia was the most common adverse event, occurring in 7 of 30 (23%) in the sirolimus group compared with 6 of 15 (40%) in the placebo group (ns). Absorption occurred within 1 hour in all volunteers. Whole blood peak concentration and area under the concentration-time curve increased proportionally with dose. Mean (+/- SD) whole blood terminal disposition half-life (t1/2), apparent oral dose clearance (Cl/F), and volume of distribution (Vss/F) were 82 +/- 12 hours, 278 +/- 117 mL/h x kg and 23 +/- 10 L/kg, respectively. Distribution of sirolimus into formed blood elements was extensive, with a mean whole blood-to-plasma ratio of 36. Single oral doses of sirolimus (0.3 to 8 mg/m2) solution were well tolerated in healthy male volunteers.     

健康志愿者单次和多次口服美敏伪麻缓释胶囊的药动学研究

目的研究美敏伪麻缓释胶囊经单、多次给药后的药动学特征,评估其在健康志愿者体内的安全性。方法 22例受试者随机、开放试验设计,研究单、多次给药药动学特征。血浆中氯苯那敏、伪麻黄碱、右美沙芬、右啡烷采用LC-MS/MS法测定,药动学参数采用Win Nonlin软件计算。安全性特征以记录到的所有不良事件来进行评价。结果整个研究过程中没有严重不良事件报告。单次口服美敏伪麻缓释胶囊后,伪麻黄碱、氯苯那敏、右美沙芬和右啡烷均在3~5 h达峰,t1/2分别为6.30±1.17、23.3±6.91、10.4±2.19、8.62±3.04 h,Cmax分别为203±40.4、5.05±1.39、4.29±3.95、1.95±0.72 ng/m L,AUClast分别为2 050±559、137±47.5、61.3±67.5、17.2±6.58μg·h/L,AUCinf分别为2 140±570、161±63.8、17.6±6.65、62.8±69.3μg·h/L。在2次/d,连续给药4 d后基本达到稳态血药浓度,伪麻黄碱、氯苯那敏、右美沙芬和右啡烷的Cmax、Cmin、AUCtau,ss与单次给药比较均有不同程度的升高,波动系数的平均值为107%~271%。结论美敏伪麻缓释胶囊多次给药后4 d达到稳态血药浓度,暴露均较单次给药后有所增高,在健康志愿者体内安全性良好。