Pharmacokinetics of oral pramiracetam in normal volunteers

The pharmacokinetics of pramiracetam, a new, investigational, cognition activator, were assessed in normal male volunteers as part of a clinical tolerance study. In a double-blind, randomized design, two groups of six subjects each received alternating placebo and single 400, 800, 1,200, and 1,600 mg oral doses of pramiracetam after an overnight fast. Mean (+/- SD) peak plasma concentrations of the four dose groups (2.71 +/- 0.54, 5.40 +/- 1.34, 6.13 +/- 0.71, 8.98 +/- 0.71 micrograms/mL) were attained between two to three hours following drug administration. The harmonic mean elimination half-life (4.5-6.5 hours), the mean total body clearance (4.45-4.85 mL/min/kg), the mean renal clearance (1.83-3.00 mL/min/kg), and the mean apparent volume of distribution (1.82-2.94 L/kg) were independent of dose, whereas the peak plasma concentrations and area under the curves increased as a linear function of dose. No significant side effects were observed at any dose level.     

Pharmacokinetics of moxisylyte in healthy volunteers after intravenous and oral administration.

The concentration-time profiles of metabolites of moxisylyte, an alpha-blocking agent, in the plasma and urine of 12 healthy volunteers were investigated after intravenous (iv) and oral (two formulations) administration. The study was conducted with an open, randomized Latin squares design. Plasma and urine levels of moxisylyte and its biotransformation products were assayed by a specific HPLC method with fluorescence detection. Plasma levels declined in a monophasic or biphasic pattern depending on the subject. Two metabolites, conjugated desacetylmoxisylyte (DAM) and conjugated monodesmethylated DAM (MDAM), were found in plasma and urine. Unconjugated DAM was found in plasma only after iv administration. The apparent elimination half-lives of unconjugated DAM, conjugated DAM, and MDAM were 0.86, 1.7, and 3 h, respectively. The total amounts of metabolites (expressed as the equivalent of DAM) excreted in the urine were 75% after i.v. administration and 68 and 69% after oral administration of the two formulations. Oral absorption appeared to be complete for the two treatments. There was no statistical difference between the two oral formulations studied.     

Pharmacokinetics of dimetindene after intravenous and oral administration to healthy volunteers

The pharmacokinetics of dimetindene (dimethindene maleate, Fenistil, CAS 3614-69-5) were studied after its intravenous and oral administration to 8 healthy male volunteers. Serum concentrations were measured for 48 h using an enzyme-linked immunosorbent assay. Pharmacokinetic parameters (AUC, t1/2, CLs, Vd and F) were calculated using the clearance approach.     

Pharmacokinetics of mifentidine after single and multiple oral administration to healthy volunteers.

1. The pharmacokinetics of mifentidine, a new long acting histamine H2-receptor antagonist, were studied using two protocols. 2. In one study, on 5 different days six normal male subjects were given 2.5, 5, 10, or 20 mg mifentidine or placebo orally 60 min before starting a 3 h continuous gastric aspiration during which time blood samples were taken for measurement of mifentidine concentration. 3. The area under the curves of mifentidine plasma levels (AUC) vs time for the four doses was linearly related to the dose for each individual subject (r = 0.972, P less than 0.001). After doses of 2.5, 5, 10 and 20 mg, mifentidine reduced hydrogen ion output by respectively 36, 37, 60 and 75% and secretory volume by 1, 17, 40, and 47%. The effects at the two highest doses were statistically significant. AUC was correlated positively with the percentage reduction in hydrogen ion output (r = 0.802, P less than 0.001) and volume (r = 0.834, P less than 0.001) over a 3 h period. 4. In the second study, the pharmacokinetics were evaluated after once-daily treatment for 14 days in seven subjects given 10 mg and in seven others subjects given 20 mg. 5. After multiple dosing, renal clearance was similar for the two doses (11.6 +/- 2.11 l h-1 for the low dose and 17.0 +/- 2.0 l h-1 for the high dose). Plasma half-life (t1/2 lambda 2) was 16.0 +/- 3.0 h after the 10 mg dose and 11.9 +/- 1.2 h after 20 mg.(ABSTRACT TRUNCATED AT 250 WORDS)     

盐酸度洛西汀肠溶片在健康人体内的药物代谢动力学研究

目的研究健康受试者口服盐酸度洛西汀肠溶片后的体内药物代谢动力学特征。方法 20名健康受试者,男女各半,单次和多次口服盐酸度洛西汀肠溶片,进行药动学实验;采用LC-MS/MS法测定血浆中盐酸度洛西汀浓度,DAS 2.0进行药动学模型拟合和参数计算,SPSS 17.0软件进行统计分析。结果盐酸度洛西汀肠溶片的体内药动学符合一室开放模型,低、中、高剂量单次给药的主要药动学参数:实测值计算的平均Cmax分别为13.85±7.37、29.86±13.87、44.47±21.80μg·L-1,Tmax分别为7.60±3.47、6.80±1.40、6.80±1.40 h,统计矩计算的平均t1/2分别为13.93±6.88、11.57±2.34、12.19±1.73 h,AUC0-t分别为268.15±204.6、531.02±385.13、843.53±634.50μg·L-1·h-1;连续给药的主要药动学参数Cmax、Cmin、Cav分别为47.37±23.59、19.47±10.55、33.09±17.11μg·L-1,Tmax、t1/2分别为6.57±1.59、13.90±2.80 h,AUC0-t为1.13±0.68 mg·L-1·h-1。结论 20～60 mg盐酸度洛西汀肠溶片呈线性动力学特点,主要药物代谢动力学参数无性别差异,多次给药后体内无明显蓄积作用。     

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.     

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。     

Pharmacokinetics of benperidol in volunteers after oral administration

Benperidol in a 4 mg single dose was administered orally to five healthy male volunteers. The drug was rapidly absorbed (tmax = 2.27 +/- 0.57 h) and largely distributed, the volume of distribution being 5.19 +/- 1.99 l.kg-1. Elimination half-life was 7.65 +/- 2.14 h. Urinary excretion represented only a minimal fraction of ingested dose (0.1 +/- 0.007%). Variability of the area under the curve makes a first-pass metabolism a reasonable possibility. Acute dystonias appeared in two subjects.     

Pharmacokinetics of rec-hirudin in healthy volunteers after intravenous administration

The pharmacokinetics of recombinant hirudin (rec-hirudin, Ciba-Geigy, CGP 39 393) in healthy volunteers after iv administration was investigated on the basis of the data from five different studies. A total of 77 plasma profiles following a single iv bolus dose of either 0.1, 0.3, 0.5, or 1 mg/kg of rec-hirudin was used for the evaulation. Plasma concentrations and especially AUC were proportional to the dose. Kinetics of rec-hirudin after a bolus iv injection were best described by a three-compartment open model. Mean apparent terminal half-life was 2.8 hr and the total clearance 0.138 L/hr per kg.     

健康男性空腹和进食后口服爱地那非片的单次药动学研究

目的:研究中国男性健康志愿者单次空腹和进食后口服枸橼酸爱地那非片的药动学.方法:试验剂量为30,60和90 mg,每组10例,其中60 mg进行空腹和餐后服用的药动学对比试验.HPLC-MS/MS测定血浆和尿样中的药物浓度,并计算其主要药动学参数.结果:受试者单次空腹口服30,60,90 mg以及餐后口服60 mg的枸橼酸爱地那非片后,其主要药动学参数:Cmax分别为(259.2±149.3),(688.8±281.9),(1 338.0±511.8)和(667.3±204.7)μg·L-1;Tmax分别为(1.58±0.98),(2.38±1.75),(1.45±0.44)和(2.40±1.13)h;t1/2分别为(4.42±0.39),(4.06±0.40),(4.33±0.81)和(4.27±0.53)h;AUCo～t分别为(1 371.3±990.6),(4 568.2±1 506.0),(10 060.1±4 246.5)和(5 089.9±1 502.4)斗g·h·L-1;AUCo～∞分别为(1 376.5±996.9),(4 576.8±1 506.5),(10 1 10.3 4-4 288.2)和(5 107.9±1 506.0)μg·h·L-1.36 h尿中原形药物的累积排出百分率分别为(0.80 4-0.39)%,(0.81±0.25)%,(1.07±0.25)%和(0.91±0.28)%.结论:单次空腹口服构橼酸爱地那非30,60和90 mg时,Cmax,AUCo～t和AUCo～∞随剂量增加的比例大于剂量增加的比例.进食对构橼酸爱地那非的药动学参数无明显影响.     

Pharmacokinetics and pharmacodynamics of verapamil in healthy volunteers after single oral and sublingual administration

5-[3,4-Dimethoxyphenethyl)-methylamino]-2-(3,4-dimethoxyphenyl)-2- isopropylvaleronitril (verapamil, Isoptin) was administered p.o. (80 mg) and via the sublingual route (20 mg as the hydrochloride) in 6 healthy volunteers. After p.o. administration the mean peak serum concentration of 125.6 ng/ml was attained on average 80 min later. The half-life for the distribution phase (t1/2a) was 0.95 h and for the elimination phase (t1/2 beta) 6.08 h. After sublingual administration the mean peak serum concentration of verapamil was 26 ng/ml attained on average after 71.7 min. The mean t1/2a was 0.73 h and the mean T1/2 beta 4.39 h. There was an 18.4 min delay after oral administration and 0.8 min delay after sublingual administration before verapamil was detected in the serum. The relative bioavailability of verapamil sublingually was 2.7 (p.o. = 1.0). There were close correlations between the verapamil concentration in serum and the prolongation of the PQ-interval (0.725 sublingually; 0.853 p.o.). Approximately three times higher concentrations of verapamil were required when given by the oral route to produce the same prolongation of the PQ-interval obtained with sublingual administration. The variability of several important pharmacokinetic parameters of verapamil was reduced by sublingual application in comparison to the oral route. The coefficient of variation for the peak concentration, time to peak and t1/2 beta were 49.7%, 25.0% and 26.4%, respectively, after sublingual administration in comparison to 120.6%, 54.7% and 68.9%, respectively, when given p.o.     

Pharmacokinetics of cefatrizine after oral administration in human volunteers

The oral bioavailability of cefatrizine was studied in four groups, each of ten healthy young male volunteers. Capsules and suspension formulations were each administered at doses of 250 and 500 mg. Both the capsules and suspensions had mean peak plasma levels at 1.6 h at both dose levels. Mean peak plasma levels were 4.1 and 4.3 micrograms/ml for the 250 mg capsule and suspension doses respectively and 7.1 and 7.5 micrograms/ml for the 500 mg capsules and suspension doses respectively. The overall mean half-life was 1.7 h. For both types of formulations and at both dose levels 63-65% of the doses were excreted in the urine as intact cefatrizine, 85% of this amount within 8 h. The overall mean renal clearance was 157 ml/min. The cefatrizine capsule and suspension formulations were completely bioequivalent in regard to both rate and extent of bioavailability. Plasma concentrations and urinary recoveries of cefatrizine were higher than those previously reported, due to precautions taken in sample collection and storage.     

Pharmacokinetics of morphine-6-glucuronide following oral administration in healthy volunteers

Aim After oral administration, morphine-6-glucuronide (M6G) displays an atypical absorption profile with two peak plasma concentrations. A proposed explanation is that M6G is hydrolysed to morphine in the colon, which is then absorbed and subsequently undergoes metabolism in the liver to morphine-3-glucuronide (M3G) and M6G. The aims of this study were to confirm and elucidate the biphasic absorption profile as well as clarify the conversion of M6G to morphine after a single oral administration of M6G in healthy volunteers. Methods The study was conducted accordingly to a nonblinded, randomised, balanced three-way crossover design in eight healthy male subjects. The subjects received 200 mg oral M6G, 50 mg oral M6G and 30 mg oral morphine. Blood samples were collected until 72 h after M6G administration and until 9 h after morphine administration. Paracetamol and sulfasalazine were coadministered with M6G as markers for the gut contents reaching the duodenum and colon, respectively. Results The plasma concentration peaks of M6G were seen at 4.0 (2.0–6.0) and 18 (12.0–24.0) h after 200 mg M6G and at 3.5 (2.0–6.0) and 21.3 (10.0–23.3) h after 50 mg M6G, which was in agreement with previously published results. The K_{M6G_abs}/K_{M6G_M6G} ratio was found to be 10. Conclusion The pharmacokinetic profile of M6G after oral administration was confirmed and with the presence of M3G and morphine in plasma after oral administration of M6G, proof seems to be found of the constant and prolonged absorption of M6G. The K_{M6G_abs}/K_{M6G_M6G} ratio of 10 indicates that the second absorption peak of M6G consists of approximately 10 times more absorbed M6G than reglucuronidated M6G. However, further studies are required to determine the precise kinetics of the second absorption peak.     

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 of rokitamycin after single administration to healthy volunteers

The pharmacokinetics of rokitamycin tablets were studied in 12 healthy volunteers in a randomized cross-over design. The doses tested were 200 mg, 300 mg, 400 mg and 600 mg, as single oral administration. Rokitamycin was absorbed quickly with Tmax for all doses around 30 min after drug intake. Total AUC and Cmax values were linearly related to the administered dose. The buffer formulation determined a low interindividual variation. The overall findings show a good similarity with the data obtained in Japanese subjects. Tolerability was very good.     

Pharmacokinetics of cefotiam after i.v. administration to healthy volunteers

The inability to calculate a definitive value for apparent volume of distribution at steady state is discussed and a method presented whereby the possible minimum and maximum values for V_ss may be determined for a drug obeying linear kinetics whose disposition may be characterized by means of a tri-exponential equation.     

单次口服瑞舒伐他汀钙片在中国健康志愿者的药代动力学

目的研究瑞舒伐他汀钙片(降血脂药)在中国健康志愿者体内单次给药的药代动力学特征。方法选择健康受试者12例,按3×3拉丁方设计,分别单次给与瑞舒伐他汀钙片5,10和20mg后,采用LC-MS测定不同时间血中瑞舒伐他汀的浓度,以BAPP软件进行数据处理,求算药代动力学参数。结果3个不同剂量组瑞舒伐他汀的主要药代动力学参数:Cmax分别为(6.54±2.06),(10.61±3.35),(22.85±7.32)ng.mL-1;AUC0-72分别为(77.83±25.43),(136.12±48.63),(275.98±81.98)h.ng.mL-1;tmax分别为(3.7±1.2),(3.8±0.8),(3.4±1.0)h;t1/2分别为(23.26±5.54),(25.64±14.02),(20.54±5.80)h;CL/F分别为(65.40±19.05),(76.96±36.47),(76.18±33.35)L.h-1;各剂量组的Cmax、AUC0-72、AUC0-∞随剂量的增加而成比例的增大,各组的Ka、Ke、tmax、t1/2ka、t1/2、MRT、CL/F等差异无统计意义。结论口服给药剂量为5～20mg时,瑞舒伐他汀钙在国人体内具有线性药代动力学特征。     

健康受试者单次口服盐酸氟西汀肠溶片的药代动力学

目的研究盐酸氟西汀肠溶片(抗抑郁症药)在健康中国人体的药代动力学特征。方法16名健康受试者单剂量口服盐酸氟西汀肠溶片90 mg (以氟西汀计),用高效液相色谱-荧光检测法测定血药浓度,用DAS 2.1.1软件计算药代动力学参数。结果健康人体单剂量口服盐酸氟西汀肠溶片90 mg,体内氟西汀及其主要代谢产物去甲氟西汀的药代动力学参数:t_(max)分别为(8.50±2.03)、(80.25±41.27)h,C_(max)分别为(68.28±16.83)、(53.25±17.12)ng·mL~(-1),t_(1/2)分别为(58.86±2.86)、(133.51±96.20) h,AUC_(0～t)分别为(4.32±1.03)、(13.60±3.65)μg·h·mL~(-1),AUC_(0～∞)分别为(4.32±1.03)、(15.12±5.06)μg·h·mL~(-1);在信噪比=3时,最低检测浓度氟西汀为4 ng·mL~(-1),去甲氟西汀为8 ng·mL~(-1)。结论氟西汀和去甲氟西汀在人体内的药-时曲线呈二室模型,该方法为液相单次提取,简便、准确、可靠。     

Pharmacokinetics of nilvadipine after single oral doses in healthy volunteers

Forty healthy male Caucasian volunteers were randomly assigned to five treatment groups to receive a placebo or a 4, 8, 12, 16 or 20 mg dose of nilvadipine. The drug was well tolerated by the subjects at all dose levels. Pharmacokinetic parameters for nilvadipine were determined using model-independent methods. There were no significant differences (p greater than 0.05) in the time to the maximum plasma concentration (Cmax) (tmax), the elimination half-life or the mean residence time among the five treatment groups. Up to doses of about 12 mg, there was a linear relationship between dose and Cmax or area under the plasma concentration-time curve (AUCO----infinity). At doses of 16 and 20 mg, the relationship between dose and Cmax or AUCO----infinity was no longer linear, suggesting that the pharmacokinetics of the drug after single oral doses greater than about 12 mg may be dose-dependent, probably due to concentration-dependent first-pass hepatic elimination of the drug.