加替沙星片的人体药代动力学及生物等效性研究

目的:研究国产加替沙星片在健康志愿者中的药物动力学及生物等效性和安全性。方法:选择24名健康成年男性受试者,随机分为2组,单次空腹口服国产或进口片剂400mg,采用HPLC法测定其血药和尿药浓度。结果:单剂量空腹口服国产和进口加替沙星片剂后体内过程均符合血管外二室模型,C_(max)分别为(4.15±1.04)mg·L~(-1)和(3.95±0.75)mg·L~(-1),t_(max)分别为(0.75±0.30)h和(0.75±0.32)h,t_(1/2)为(6.77±1.58)h和(7.18±0.98)h,AUC_(0-t)分别为(31.83±3.84)mg·h·L~(-1)和(32.41±3.81)mg·h·L~(-1)。48 h内平均累积尿排出率分别为(79.53±5.79)%和(79.89±6.09)%。结论:国产片剂与进口片剂相比,主要药物动力学参数经统计学处理均无显著性差异,其相对生物利用度为(98.41±7.62)%。     

高脂饮食对盐酸依格列汀在中国健康人体内药代动力学的影响北大核心CSCD

目的观察中国健康受试者空腹和高脂高热量饮食情况下口服盐酸依格列汀片的药代动力学特征。方法 12名健康受试者单剂量、自身交叉口服依格列汀片50 mg。用HPLC-MS/MS法测定人血浆中依格列汀的浓度,用Phoenix Win Nonlin 6.3软件按非房室模型计算药代动力学参数。结果空腹和进食后的主要药代动力学参数如下:C_(max)分别为(187.00±47.30),(163.00±61.10)ng·m L^(-1);t_(1/2)分别为(24.60±3.98),(24.20±4.70)h;AUC_(last)分别为(2.05±0.29),(1.71±0.30)mg·L^(-1)·h;AUC_(0-∞)分别为(2.09±0.30),(1.74±0.31)mg·L^(-1)·h;t_(max)中位数(范围)分别为1.25(0.5,4)h和1.75(1,3)h。结论高脂饮食对依格列汀的药代动力学有影响,但影响程度较小:高脂饮食后服药较空腹条件下服药,AUC_(last)减少16.8%,C_(max)减少15.1%。高脂饮食对依格列汀的t_(max)无显著影响。     

盐酸奥洛他定片在健康人体的药代动力学

目的 研究中国健康志愿者口服不同剂量盐酸奥洛他定片(抗过敏药)的药代动力学.方法 12名中国健康志愿者采用随机自身交叉试验设计,口服单剂量盐酸奥洛他定片(5,10,20 mg).用高效液相色谱-串联质谱法测定血药浓度和尿药浓度.结果 盐酸奥洛他定5,10,20mg剂量组主要药代动力学参数:C_(max)分别为(76.73±26.61),(133.61±61.63),(270.44±115.19)μg·L~(-1);t_(max)分别为(0.75±0.19),(0.96±0.29),(0.83±0.32)h;t_(1/2)分别为(5.20±2.47),(6.82±3.04),(6.87±3.06)h;AUC_(0-t)分别为(246.70±66.07),(439.19±185.03),(904.69±300.21)μg·h·L~(-1);AUC_(0-∞)分别为(248.36±65.81),(442.02±186.46),(907.49±299.92)μg·h·L~(-1).受试者单次口服3个剂量组的盐酸奥洛他定片后,尿中原形药物的排泄率平均约为54.6%.结论 血浆中奥洛他定的C_(max)和AUC显示线性药代动力学特征.受试者服用盐酸奥洛他定片5,10,20 mg后,药代动力学参数经单因素方差分析显示无性别差异.     

盐酸非索非那定片在中国健康受试者中的生物等效性研究北大核心CSCD

目的评价盐酸非索非那定片在中国健康受试者的生物等效性和安全性。方法用随机、开放、空腹四周期、餐后两周期、重复交叉、自身对照的试验设计。空腹28例/餐后40例健康受试者口服盐酸非索非那定片受试制剂和参比制剂60 mg,用液相色谱-串联质谱法测定血药浓度,用非房室模型计算非索非那定的药代动力学参数。结果空腹试验中盐酸非索非那定片受试制剂和参比制剂的主要药代动力学参数如下:C_(max)分别为(242.00±109.00)和(230.00±97.90)ng·mL^(-1),AUC_(0-t)分别为(1483.77±444.73)和(1469.81±501.47)ng·mL^(-1)·h,AUC_(0-∝)分别为(1533.18±448.35)和(1525.18±505.80)ng·mL^(-1)·h。2种制剂的C_(max)、AUC_(0-t)和AUC_(0-∞)经对数转换后的90%置信区间分别为96.13%~114.62%、96.53%~109.88%和96.23%~109.18%。餐后试验中盐酸非索非那定片受试制剂和参比制剂的主要药代动力学参数如下:C_(max)分别为(98.10±32.50)和(106.00±29.90)ng·mL^(-1),AUC_(0-t)分别为(622.24±165.84)和(627.53±164.37)ng·mL^(-1)·h,AUC_(0-∝)分别为(677.04±174.82)和(684.69±177.12)ng·mL^(-1)·h。2种制剂的C_(max)、AUC_(0-t)和AUC_(0-∞)经对数转换后的90%置信区间分别为83.31%~100.86%、94.96%~103.30%和94.62%~103.37%。结论在空腹和餐后条件下,盐酸非索非那定片受试制剂与参比制剂具有生物等效性,安全性良好。     

盐酸曲美他嗪缓释片在中国健康受试者中的生物等效性研究北大核心CSCD

目的评价盐酸曲美他嗪缓释片仿制药与原研药在中国健康受试者空腹和餐后条件下给药的生物等效性与安全性。方法按单中心、随机、开放、单剂量、两制剂、两序列、双周期、交叉研究设计,共纳入47例(空腹试验23例,餐后试验24例)成年男性和女性受试者随机交叉给药,分别单次口服受试制剂或参比制剂35 mg,用LC-MS/MS法测定血浆中曲美他嗪的浓度,用Win Nonlin 6.4软件按非房室模型计算药代动力学参数,并进行生物等效性评价。结果空腹组盐酸曲美他嗪缓释片受试制剂和参比制剂的主要药代动力学参数如下:C_(max)分别为(65.62±13.92)和(66.39±15.15)μg·L^(-1),t_(max)分别为(3.96±1.15)和(4.26±1.21)h,AUC_(0-t)分别为(909.43±219.81)和(920.65±230.09)μg·L^(-1)·h,AUC_(0-∞)分别为(921.57±226.17)和(933.35±236.56)μg·L^(-1)·h;餐后组盐酸曲美他嗪缓释片受试制剂和参比制剂的主要药代动力学参数如下:C_(max)分别为(69.78±14.65)和(65.99±13.73)μg·L^(-1),t_(max)分别为(4.83±0.82)和(4.71±1.00)h,AUC_(0-t)分别为(766.54±165.62)和(793.50±163.67)μg·L^(-1)·h,AUC_(0-∞)分别为(774.17±167.43)和(802.04±166.02)μg·L^(-1)·h。在空腹和餐后条件下,受试制剂和参比制剂主要药代动力学参数90%置信区间均在80.00%125.00%。结论空腹与餐后单次口服盐酸曲美他嗪缓释片仿制药与原研药在中国健康受试者体内均有生物等效性。     

艾司西酞普兰片在中国健康受试者体内的生物等效性研究北大核心CSCD

目的研究艾司西酞普兰在空腹和餐后条件下中国健康受试者体内的生物等效性。方法用单剂量、随机、开放、两周期、两序列、双交叉试验设计。空腹和餐后试验各纳入26例健康受试者,每周期空腹或餐后单次口服艾司西酞普兰片受试制剂或参比制剂10 mg。用HPLC-MS/MS法测定艾司西酞普兰血药浓度,用WinNonlin 8.0计算艾司西酞普兰药代动力学参数,评价受试制剂和参比制剂的生物等效性。结果空腹试验中艾司西酞普兰受试制剂和参比制剂的主要药代动力学参数:C_(max)分别为(13.80±2.71)和(14.10±3.16)ng·mL^(-1);AUC_(0-t)分别为(450.52±178.35)和(428.26±153.18)ng·mL^(-1)·h;AUC_(0-∞)分别为(491.35±219.49)和(459.47±182.20)ng·mL^(-1)·h。餐后试验中艾司西酞普兰受试制剂和参比制剂的主要药代动力学参数:C_(max)分别为(15.10±2.68)和(14.00±2.59)ng·mL^(-1);AUC_(0-t)分别为(489.40±155.25)和(458.61±107.06)ng·mL^(-1)·h;AUC_(0-∞)分别为(527.82±205.84)和(486.83±131.00)ng·mL^(-1)·h。空腹和餐后试验(受试制剂/参比制剂)的C_(max)、AUC_(0-t)和AUC_(0-∞)的几何均值比90%置信区间均在80.00%~125.00%内。空腹和餐后试验过程中不良事件发生率分别为57.69%(15例/26例)和38.46%(10例/26例),且试验过程均无严重不良事件及非预期不良事件发生。结论空腹和餐后给药条件下,2种艾司西酞普兰片制剂具有生物等效性,且安全性良好。     

格列美脲口腔崩解片人体药动学及相对生物利用度

目的:研究健康受试者口服格列美脲口腔崩解片的人体药动学及相对生物利用度。方法:18名健康志愿者随机交叉单剂量口服格列美脲受试片与对照片4mg,采用柱前衍生化 HPLC-紫外法测定其血药浓度。结果:受试片与对照片的主要药动学参数 t_(max) 分别为(3.00±0.73)和(3.25±0.85)h,C_(max)分别为(313.1±99.3)和(303.2±104.5)μg·L~(-1),t_(1/2Ke)分别为(7.337±2.190)和(8.239±2.631)h,AUC_(0-t)分别为(1767.2±598.3)和(1714.1±528.3)μg·h·L~(-1),AUC_(0-∞)分别为(1956.3±598.1)和(1945.4±682.0)μg·h·L~(-1)。受试片的相对生物利用度为100.1%±18.2%。结论:两种片剂具有生物等效性。     

盐酸维拉帕米迟释片及其普通片在健康人体的生物等效性

目的研究盐酸维拉帕米迟释片(抗心绞痛药)在健康人体内的药代动力学特征,并评价迟释片和普通片剂间的生物等效性。方法24名健康男性志愿受试者随机交叉单剂量口服盐酸维拉帕米迟释片(受试制剂)和普通片(参比制剂)各80 mg,采用高效液相色谱法按设计时间点采集血样进行分析测定,绘制血药浓度-时间曲线,计算相关的药代动力学参数。结果受试者口服受试制剂和参比制剂后,血浆中维拉帕米的主要药代动力学参数:t_(max)分别为(5.2±1.6)和(2.3±1.2)h;C_(max)分别为(39.0±21.0)和(36.1±13.7)ng·mL~(-1);t_(1/2)分别为(6.3±2.2)和(6.6±1.7)h;AUC_(0-t)分别为(223.6±109.9)和(210.3±92.7)ng·h·mL~(-1);AUC_(0-∞)分别为(239.8±113.2)和(225.1±95.7)ng·h·mL~(-1)。受试制剂的相对生物利用度为(113.5±42.9)%。结论盐酸维拉帕米迟释片和普通片剂之间体内生物作用等效。     

国产氧氟沙星在健康成人中的药物动力学和生物利用度研究

本文采用专一性强、灵敏度高的HPLC 荧光检测法,测定氧氟沙星血、尿浓度。对国产氧氟沙星片在12例健康受试者中进行药物动力学和生物利用度研究。氧氟沙星片口服给药多数人为一房室模型,其主要药动学参数,国产片和进口片分别为:T_(1/2)6.2±1.3和6.1±1.5h;Vd 1.5±0.4和1.6±0.5l/kg;C_(max)8.6±2.5umol/L 和7.9±1.4μmol/L;T_(max)0.6±0.5和0.6±1.0h;Cl_T13±4和12±4 l/min;AUC_(o-∞)76±23和73±21μmol/L·h。其相对生物利用度为104.9±9.9%。     

厄贝沙坦片在中国健康人体内的生物等效性研究北大核心CSCD

目的研究厄贝沙坦片在中国健康人体内的生物等效性。方法采用单中心、随机、开放、单剂量、两周期、2×2交叉试验设计,空腹试验和餐后试验中分别有32例受试者口服厄贝沙坦片受试制剂或参比制剂0.15 g。LC-MS/MS法测定给药后不同时间厄贝沙坦的血药浓度,并用Phoenix WinNonlin 7.0软件计算主要药代动力学参数,判定两制剂是否等效。结果空腹试验受试制剂和参比制剂厄贝沙坦的主要药代动力学参数:C_(max)分别为(2242.4±631.5),(2327.3±821.0)ng·mL^(-1),AUC_(0-t)分别为(9953.2±3339.6),(10218.5±2985.3)h·ng·mL^(-1),AUC_(0-∞)分别为(10201.7±3377.9),(10516.5±2995.6)h·ng·mL^(-1),T_(max)均为1.50 h;t_(1/2)分别为(12.3±5.8),(15.1±10.3)h。餐后试验受试制剂和参比制剂厄贝沙坦的主要药代动力学参数:C_(max)分别为(2691.8±663.7),(2598.8±877.1)ng·mL^(-1),AUC_(0-t)分别为(10129.8±3783.9),(9538.6±3151.8)h·ng·mL^(-1),AUC_(0-∞)分别为(10353.1±3792.3),(9720.1±3162.0)h·ng·mL^(-1),T_(max)均为1.50 h;t_(1/2)分别为(12.5±7.6),(10.3±5.2)h。受试制剂与参比制剂C_(max)、AUC_(0-t)、AUC_(0-∞)几何均值比的90%置信区间均完全落在80.00%~125.00%。结论2种厄贝沙坦片在中国健康志愿者体内具有生物等效性。     

Absolute bioavailability of sitagliptin, an oral dipeptidyl peptidase-4 inhibitor, in healthy volunteers

The purpose of this study was to determine the absolute bioavailability of sitagliptin, an orally active, potent and highly selective dipeptidyl peptidase-4 inhibitor recently approved in the United States for the treatment of type 2 diabetes. The effect of a high fat meal on sitagliptin pharmacokinetics was also assessed. The study was performed in two parts. Intravenous doses (2 h infusion) of 25, 50 and 100 mg were administered double-blind to 10 (8 active, 2 placebo) subjects in a fixed-sequence manner in Part I. In Part II, 12 subjects were randomized to each of three open-label treatments: an intravenous 100 mg dose; a single oral 100 mg final market image tablet administered following a high fat meal and a single oral 100 mg final market image tablet administered fasted. Following each dose, plasma and urine were collected at pre-specified times for evaluation of sitagliptin pharmacokinetics. All doses were generally well tolerated in both parts of the study. Following rising intravenous doses of sitagliptin, AUC(0-infinity) increased dose-proportionally, indicating that plasma clearance is independent of dose over the dose range evaluated. Renal clearance of unchanged sitagliptin accounted for approximately 70% of the total plasma clearance of sitagliptin, indicating that sitagliptin is primarily cleared via renal excretion. Averaged across doses, the mean total plasma clearance was 416 ml/min. The mean absolute bioavailability of sitagliptin was 87% with a 90% CI of (81%, 93%). The AUC(0-infinity) and C(max) geometric mean ratios (fed/fasted) and 90% CIs were 1.03 (0.97, 1.11) and 0.94 (0.86, 1.03), respectively, and were contained within the bounds of (0.80, 1.25). Additionally, the high-fat meal had no significant effect on T(max) or apparent terminal t(1/2). Thus, food does not affect the pharmacokinetics of sitagliptin and therefore can be administered without regard to food. Copyright (c) 2007 John Wiley & Sons, Ltd.     

Evaluation of the absolute oral bioavailability and bioequivalence of erlotinib, an inhibitor of the epidermal growth factor receptor tyrosine kinase, in a randomized, crossover study in healthy subjects

A randomized, open-label, 2-period crossover study was conducted to evaluate the bioequivalence of 6 tablets of erlotinib 25 mg and 1 tablet of erlotinib 150 mg (arm A, n = 42) and the oral bioavailability of the 150-mg tablet versus a 25-mg intravenous infusion (arm B, n = 20) in healthy subjects. The washout period was 2 weeks between treatments. Plasma concentrations of erlotinib and its active metabolite, OSI-420, were measured after each dose. The ratios of geometric means for AUC(0-infinity) and Cmax of erlotinib following 6 tablets of erlotinib 25 mg and 1 tablet of erlotinib 150 mg were (1 and 0.95) within the predefined bioequivalence range of 0.80 to 1.25. The mean absolute oral bioavailability, using compartmental analysis, was estimated as 59% (95% confidence interval, 55%-63%). Overall, 6 tablets of erlotinib 25 mg are bioequivalent to a single 150-mg tablet. Both intravenous and oral erlotinib were generally well tolerated with an estimated bioavailability of 59% following oral administration.     

Absolute Bioavailability of Halofantrine-Hcl: Effect of Ranitidine and Pentagastrin Treatment

Abstract

The first part of this study dealt with determination of the absolute oral bioavailability of halofantrine using six beagle dogs that were randomly assigned to two groups. The beagles in Group I had a single S mg/kg intravenous dose of halofantrine in the first period and a single 250 mg oral dose of halofantrine tablet in the second period with a washout period of six weeks. Those in Group II received the intravenous and oral doses in the opposite order.

The effect of gastric pH on the absolute bioavailability was evaluated in the second part of the study. Six beagles received a single 5 mg/kg intravenous dose in the first period. They were randomly assigned to two groups six weeks after the intravenous dose. Those in Group I had 6 μg/kg pentagastrin intravenously 30 minutes before a single 230 mg oral dose of halofantrine tablet in the second period. They received 2.5 mg/kg intramuscular doses of ranitidine 10 and 2 hours before a single 250 mg oral dose of halofantrine tablet in the third period. Those in Group n received the above treatments in opposite order. A six weeks washout period separated treatment periods two and three.

Blood samples were obtained at specified times over 28 days following drug administration. Quantitation of halofantrine in plasma was by HPLC using fluorescence detection.

The absolute oral bioavailability by AUC of halofantrine was low and highly variable with a mean (±SD) of 6.3 (4.7)%. A value of 7.9 (5.2)%, not significantly different from control, was observed following inhibition of gastric acid secretion by ranitidine. However, statistically significant (p≤0.05) increases in halofantrine bioavailability with a value of 16.1 (7.0)% was observed following stimulation of gastric acid secretion by pentagastrin.     

艾普拉唑肠溶片在中国健康人体中药代动力学及绝对生物利用度研究

目的 采用液相色谱串联质谱(UPLC-MS/MS)分析方法研究艾普拉唑肠溶片在中国健康人体中的吸收特性. 方法 采用随机交叉自身对照试验设计,16名健康受试者随机等分成4组,先后口服艾普拉唑肠溶片或静脉注射艾普拉唑钠,采用UPLC-MS/MS测定血浆药物浓度.利用WinNonlin(V6.1)软件标准非房室模型方法进行药代动力学参数的计算. 结果 注射用艾普拉唑钠(10mg)的主要药代动力学参数:最大血药浓度(Cmax)为(834.3±101.2)ng/mL,消除半衰期(t1/2)为(3.4±0.9)h,表观分布容积(Vz)为(14.0±2.2)L, 0到t时间药时曲线下面积(AUC0_t)为(3520.9±915.3)ng·h/mL,血浆清除率(CL)为(3.0±0.9)L/h.艾普拉唑肠溶片(10mg)的主要药代动力学参数:Cmax为(347.9±176.3)ng/mL,t1/2为(3.5±0.8)h,Vz为(29.1±12.2)L,AUC0_t为(1970.2±834.7)ng·h/mL,CL为(5.9±2.5)L/h.与静脉给药相比,口服艾普拉唑肠溶片的绝对生物利用度为(55.2±13.9)%. 结论 艾普拉唑肠溶片生物利用度良好,适于开发.     

Absolute bioavailability and absorption characteristics of divalproex sodium extended-release tablets in healthy volunteers

Conventional delayed-release, enteric-coated divalproex sodium tablet has an absolute bioavailability of approximately 100%. Divalproex sodium extended-release (ER) tablet is a novel formulation of valproic acid (VPA) designed to release the drug slowly at a constant zero-order rate. The purpose of this study was to evaluate the absolute bioavailability and absorption characteristics of divalproex ER. Healthy adult volunteers (n = 16) received divalproex ER and intravenous VPA in crossover fashion. Absolute bioavailability was calculated as the divalproex ER/intravenous VPA ratio of area under the curve extrapolated to infinity. The duration and rate of absorption of VPA from divalproex ER tablets were determined by deconvolution analysis. The geometric mean absolute bioavailability of divalproex ER was 0.896. The mean (coefficient of variation) duration of drug absorption from divalproex ER was 21.8 (17%) hours, and the zero-order absorption rate was 21.6 (24%) mg/h for a 500-mg tablet. Divalproex ER has a lower absolute bioavailability than conventional divalproex tablets but exhibits good extended-release characteristics without any dose dumping.     

Pharmacokinetics and dose proportionality of D2-agonist MK-458 (HPMC) in parkinsonism.

To investigate the pharmacokinetic profile, bioavailability, and dose proportionality of the D2-agonist MK-458 (hydroxypropylmethylcellulose tablet, a sustained release formulation), a 4-period crossover study was conducted in 10 patients with mild to moderate Parkinson's disease (mean age = 63 y; 1 woman, 9 men). Following a titration phase to induce tolerance, each patient was given single oral doses of 6, 12 and 18 mg and a single intravenous 40 micrograms dose (5 micrograms/h over 8h). The maximum concentrations of MK-458 observed in plasma after oral administration were 139, 240 and 344 ng/L for the 6, 12 and 18 mg doses, respectively, and occurred after 8.0, 9.0 and 5.5 h, respectively. Mean areas under the plasma concentration-time curves were 1728, 2849 and 5484 ng/L.h, respectively. The mean plasma half-life was 3.8 h and mean plasma clearance was 3390 ml/min (203.4 L/h). The bioavailability (approximately 5%) was very similar for the 3 tablet formulations tested. The disposition of MK-458 was independent of the dose over the range of doses studied.     

Linezolid absolute bioavailability and the effect of food on oral bioavailability.

Linezolid is a novel oxazolidinone antibiotic that has a spectrum of activity encompassing a variety of Gram-positive bacteria. The objectives of this study were twofold: (1) to compare the absorption of linezolid tablets given immediately following a high-fat meal with the absorption of tablets administered while fasting, and (2) to assess the bioavailability of a 375-mg oral dose given while fasting relative to a 375-mg dose of linezolid sterile solution given intravenously. Venous blood samples were taken over the 48 h following the single dose administration of both the oral and intravenous (IV) treatment. Samples were subsequently frozen for the determination of linezolid concentrations by HPLC. The only statistically significant difference between the fasted and the fed treatment was in peak plasma concentration, with the mean C(max) for fasted subjects being 23% greater than that for subjects after consumption of a high-fat meal. Comparable AUC(0-infinity) values were measured under both conditions, indicating that the overall extent of absorption is the same. Therefore, the difference in C(max), while statistically significant, should not affect the therapeutic efficacy of linezolid when it is administered with food. There were no statistically significant differences in AUC(0-infinity), CL or half-life between the fasted oral treatment and the intravenous treatment. As expected, C(max) was statistically different between the two treatments. However, the mean absolute bioavailability (F) of the tablet, using the IV sterile solution as the reference treatment, was 103% (+/-20%).     

The pharmacokinetics of escitalopram after oral and intravenous administration of single and multiple doses to healthy subjects

The pharmacokinetics of escitalopram (S-citalopram) and its principal metabolite, S-demethylcitalopram (S-DCT), were investigated after intravenous and oral administration to healthy subjects. After intravenous infusion of escitalopram, the mean systemic clearance and volume of distribution were 31 L/h and 1,100 L, respectively. After oral administration of single or multiple doses, the absorption was relatively fast, with the maximum observed plasma or serum concentration (C(max)) attained after 3 to 4 hours. The mean half-lives were 27 and 33 hours, respectively; steady state was attained within 10 days. The area under the plasma or serum concentration time curve from time zero to 24 hours and C(max) was both linear and proportional to the dose. The apparent volume of distribution was around 20 L/kg. Comparison of the systemic and oral clearance implied a high absolute bioavailability. There was no evidence of interconversion from S-citalopram to R-citalopram either in plasma or in urine. Concurrent intake of food had no effect on the pharmacokinetics of escitalopram or its metabolite. All treatments were well tolerated.     

Levofloxacin pharmacokinetics in children

Levofloxacin is a broad-spectrum fluoroquinolone antibiotic with activity against many pathogens that cause bacterial infections in children, including penicillin-resistant pneumococci. To provide dosing guidance for children, 3 single-dose, multicenter pharmacokinetic studies were conducted in 85 children in 5 age groups: 6 months to <2 years, 2 to <5 years, 5 to <10 years, 10 to <12 years, and 12 to 16 years. Each child received a single 7-mg/kg dose of levofloxacin (not to exceed 500 mg) intravenously or orally. Plasma and urine samples were collected through 24 hours after dose. Pharmacokinetic parameters were estimated and compared among the 5 age groups and to previously collected adult data. Levofloxacin absorption (as indicated by C(max) and t(max)) and distribution in children are not age dependent and are comparable to those in adults. Levofloxacin elimination (reflected by t1/2 and clearance), however, is age dependent. Children younger than 5 years of age clear levofloxacin nearly twice as fast (intravenous dose, 0.32+/-0.08 L/h/kg; oral dose, 0.28+/-0.05 L/h/kg) as adults and, as a result, have the total systemic exposure (area under the plasma drug concentration-time curve) approximately one half that of adults. The levofloxacin area under the plasma drug concentration-time curve (dose normalized) in children receiving a single dose of the oral liquid formulation is comparable to that in children receiving the intravenous formulation. To provide compatible levofloxacin exposures associated with clinical effectiveness and safety in adults, children > or =5 years need a daily dose of 10 mg/kg, whereas children 6 months to <5 years should receive 10 mg/kg every 12 hours.     

Solifenacin demonstrates high absolute bioavailability in healthy men

OBJECTIVE: Solifenacin succinate (YM905; Vesicare) is a promising new bladder selective muscarinic receptor antagonist under investigation for the treatment of overactive bladder. This study was designed to assess the absolute bioavailability of a single oral dose of solifenacin 10 mg, which is twice the suggested starting dose. STUDY DESIGN: Single-centre, open-label, randomised, two-period, crossover, single-dose study. METHODS: Solifenacin was administered orally as a 10 mg dose and intravenously as a 5 mg dose. Oral and intravenous (IV) doses were divided by a washout period of > or =14 days. STUDY PARTICIPANTS: The study group consisted of 12 healthy young men, aged 20-45 years, nine of whom completed the study. RESULTS: The pharmacokinetic analysis comprised nine subjects. A single oral dose of solifenacin 10 mg had a high absolute bioavailability of 88.0% (95% confidence interval 75.8, 102.1), low clearance (9.39 L/h [SD 2.68]), and an extensive mean volume of distribution at steady state (599L [SD 86]). Only 7% of solifenacin was excreted intact in the urine. Single oral and IV administration of solifenacin was well tolerated in this study. The most common adverse events related to drug treatment were headache and somnolence. CONCLUSIONS: Pharmacokinetic analyses of single oral and IV doses of solifenacin demonstrated that the drug has a high absolute oral availability of 88%. This finding suggests that solifenacin may have a higher and less variable bioavailability than other antimuscarinic agents.