食物对氧氟沙星生物利用度的影响

在空腹和进食条件下分别交叉给９名健康志愿者（男性，平均年龄２５±ｓ７ａ）口服氧氟沙星片２×１００ｍｇ，采用ＨＰＬＣ法测定经时过程血药和尿药浓度，并计算其药物动力学参数。结果表明：进食对氧氟沙星片剂生物利用度无明显影响，但可延缓该药的吸收。     

林可霉素对庆大霉素药动学的影响

本文运用荧光偏振免疫分析法(FPIA),测定了林可霉素与庆大霉素肌注合并用药前后的5.例受试者庆大霉素血清浓度,数据按单室模型回归分析取得药动学参数,并进行统计学处理,结果发现合并用药前后药动学参数无明显变化(P>0.05)。     

林可霉素溶液剂和片剂的生物利用度比较

本文采用微生物法测定了12名健康志愿者交叉口服750mg林可霉素溶液剂和片剂后的血药浓度,经IBM计算机药动学程序PKBP—NI的拟合和统计程序POMS分析,评价比较了这两种制剂的药动学参数和生物利用度。结果表明:溶液剂的口服吸收稍快于片剂,而片剂的吸收略优于溶液剂,但两者的药动学参数均无显著差异(p>0.05)。两者的生物利用度是相似的,其相对生物利用度F(AUC_(0→∞)溶液剂/AUC_(0→∞)片剂)为92.3%。     

盐酸林可霉素口服液在人体内药动学和生物利用度

８名健康受试者一次口服盐酸林可霉素的口服液和片剂两种剂型后，用高效液相－电化学（ＨＰＬＣ－ＥＤ）法测定盐酸林可霉素的血药浓度，其血药浓度符合一室模型。结果盐酸林可霉素口服液和片剂主要药动学参数分别为：Ｃ_(ｍａｘ)：５．０±０．５ｍｇ／Ｌ和４．３±０．６ｍｇ／Ｌ；Ｔｍａｘ：２．１６±０．２１ｈ和２．３±０．６ｈ；ＡＵＣ：３７±７（ｍｇ·ｈ）／Ｌ和３６±７（ｍｇ·ｈ）／Ｌ。盐酸林可霉素口服液对片剂的相对生物利用度为１０４±５％，可认为口服液与片剂生物等效。     

氧氟沙星片的药物动力学和生物利用度

在８例健康志愿者中进行国产与进口氧氟沙星片药物动力学和生物利用度研究。随机交叉试验设计单剂量口服４００ｍｇ，用ＨＰＬＣ测定血药浓度，按非室模型计算，求得２种制剂各项药物动力学参数，无显著性差异（Ｐ＞０．０５），以进口药片为标准（Ｆ＝１）求得国产药片的相对生物利用度为９２．２％。     

头孢氨苄缓释片和普通胶囊的多剂量生物利用度和药物动力学比较

目的：比较头孢氨苄缓释片和普通胶囊的多剂量生物利用度和药物动力学。方法：１０例健康志愿者随机交叉口服ＣＥＸ缓释片５００ｍｇ，ｑ１２ｈ，ＣＥＸ普通胶囊２５０ｍｇ，ｑ６ｈ，服３ｄ达 后进行波动试验和稳态药物动力学研究，ＨＰＬＣ法测定血药浓度。结论：ＣＥＸ缓释片达峰时间延长，维持有效血药浓度的时间较长。     

西咪替丁漂浮片和普通片在人体的相对生物利用度比较

用HPLC法测定了西咪替丁漂浮片在健康受试者体内的血药浓度,比较了漂浮片即普通片在人体的相对生物利用度,经统计学处理,两者 AUC 无显著差异,F_R 为1.058±0.331。Cmax、tmax、k_a 均有显著差异(p<0.01),漂浮片在人体有明显缓释作用。     

格列吡嗪胶囊剂的相对生物利用度和生物等效性评价

９名健康志愿者，随机交叉口服进口和国产格列吡嗪制剂，利用ＨＰＬＣ测定血浆中药物的达峰浓度Ｃｍａｘ分别为５９１±１７８ｎｇ·Ｌ－１和５２６±１８８ｎｇ·Ｌ－１，２种制剂的消除半衰期　分别为３．２±０．５和３．５±０．８ｈ，血药一时曲线下面积分别为４９１５±１４３２和４８１２±１３０９ｎｇ·ｈ·Ｌ－１。药一时曲线符合一级吸收的单房室模型，国产格列吡嗪片的相对生物利用度Ｆ为０．９８，表明２种制剂具有生物等效性。     

食物对依诺沙星生物利用度的影响

在空腹和食物条件下分别交叉给9名健康志愿者(男,平均年龄26±6a)口服依诺沙星胶囊剂2×200mg,从尿药排泄量比较生物利用度。结果空腹和食物条件48h尿药排泄总量分别为69％±9％,67％±7％(P>0.05)。表明食物对依诺沙星的生物利用度无明显影响。但食物条件可延缓该药的吸收速率。     

Effect of aluminium phosphate on the bioavailability of cimetidine and prednisolone

Summary Ten fasting subjects received 200 mg cimetidine orally either with water or 11 g aluminium phosphate mixture in a randomized, single dose, two-way cross-over study. Blood samples were taken for 12 h and urine was collected for 24 h. Cimetidine in plasma and urine was analysed by HPLC. There were no significant differences between the treatments with respect to peak plasma concentration, time to peak plasma concentration, area under the plasma concentration-time curve, and urinary excretion. In 12 healthy subjects the absorption of prednisolone was investigated when given alone and together with 11 g aluminium phosphate. Blood samples were taken over 16 h and prednisolone in plasma was analysed by HPLC. There were no significant differences in the values of area under curve (AUC), C_max and t_max. The results indicate that aluminium phosphate does not reduce the bioavailability of cimetidine and prednisolone.     

Differential effects of cimetidine on theophylline metabolic pathways

Summary The effects of cimetidine (1 g/day) on theophylline disposition and metabolism were examined in smokers and non-smokers for single dose intravenous and chronic oral administration of theophylline. In the intravenous study the effect of cimetidine on plasma theophylline clearance was more marked in smokers (22.7% reduction) than in non-smokers (12.2% reduction). Similarly, in the multiple dose study the effect of cimetidine on theophylline clearance was greater in smokers (28.3% decrease) than in non-smokers (11.3% decrease). The reduction in clearance was largely due to a reduction in metabolic clearances by 3-demethylation (Cl_3DM) and 1-demethylation (Cl_1DM) with no significant effect on clearance by 8-oxidation (Cl_80X). There was a strong correlation between Cl_3DM and Cl_1DM (r=0.98, p<0.001) in both control and cimetidine study phases, whereas other correlations between partial clearances were less marked and were not apparent during the cimetidine phase. The results are consistent with the view that 1- and 3-demethylation of theophylline are carried out by a common form of cytochrome P-450 which is selectively induced by cigarette smoking and preferentially inhibited by cimetidine.     

Use of single doses and rapid sampling to detect interactions with cimetidine

Summary In this study the well-established interaction between cimetidine and theophylline has been demonstrated using only a single dose of cimetidine. Eleven healthy subjects were given a 30 min infusion of theophylline on two separate occasions and plasma levels were monitored at frequent intervals. During one of the studies, a single 400 mg oral dose of cimetidine was given after collection of the 3 h sample. After normalisation of the control and test curves, a deflection was apparent in the test theophylline elimination curve in 9 out of 11 subjects. This method may provide a rapid screening method to detect such interactions.     

Penbutolol pharmacokinetics: the influence of concomitant administration of cimetidine

Summary A possible interaction of penbutolol and cimetidine was investigated in healthy volunteers treated orally for 7 days.The plasma levels of unmetabolised penbutolol showed a slight but non-significant increase. The biphasic elimination kinetics of penbutolol (half-lives 0.8 and 17 h) was not affected by coadministration of cimetidine. Plasma levels of penbutolol were not significantly altered by chronic treatment with cimetidine, whereas the levels of 4-hydroxypenbutolol and 4-hydroxypenbutolol glucuronide were significantly reduced.     

Effect of sucralfate on the bioavailability of cimetidine

Summary Twelve, healthy fasting, subjects received 200 mg cimetidine orally either with water or 1 g sucralfate in a randomized, single dose, two-way crossover study. Blood samples were taken for 12 h and urine was collected for 24 h. Cimetidine in plasma and urine was analysed by HPLC. There was no significant difference between the two treatments in peak plasma concentration, time to peak plasma concentration, area under the plasma concentration-time curve and urinary excretion. The results indicate that sucralfate did not reduce the bioavailability of cimetidine.     

氟罗沙星胶囊在健康人体的药动学研究及生物等效性评价

目的研究氟罗沙星胶囊在健康人体内的相对生物利用度和生物等效性。方法以18名健康志愿者为受试对象,采用同体交叉试验方法,分别单剂量口服受试制剂或参比制剂各200 mg,采用HPLC法测定血浆中药物浓度。结果受试制剂和参比制剂的tmax分别为（1.39±0.50）和（1.39±0.50）h,Cmax分别为（1.86±0.42）和（1.89±0.41）μg.mL-1,t1/2分别为（11.08±1.43）和（10.94±1.73）h,AUC0～48分别为（21.97±3.80）和（21.95±4.58）μg.h.mL-1,AUC0～∞分别为（23.42±3.93）和（23.39±4.74）μg.h.mL-1。结论受试制剂与参比制剂生物等效。     

The influence of cimetidine on debrisoquine 4-hydroxylation in extensive metabolizers

Summary We have studied the effect of cimetidine (800 mg·day^–1) administration for three days on debrisoquine 4-hydroxylation in nine healthy extensive metabolizers.The debrisoquine metabolic ratio was significantly increased (p<0.01), but the new ratios remained in the extensive metabolizer range (<12.6).These data suggest that pre-treatment with cimetidine in usual therapeutic doses will impair debrisoquine 4-hydroxylation, but not enough to alter the apparent oxidation phenotype.