头孢克洛缓释片的研制及人体药物动力学研究

以HPMC为阻滞剂制备头孢克洛缓释片,并测定体外释放度和人体内血药浓度.结果表明,单剂量口服375mg头孢克洛自制缓释片和参比制剂(商品名Ceclor CD)后的tmax、Cmax、AUCo-τ和MRT分别为(1.42±0.20)和(1.25±0.27)h、(3.58±0.30)和(3.42±0.28)μg/ml、(12.31±1.8)和(11.65±1.26)μg·h·ml-1、(2.77±0.27)和(2.66±0.23)h.统计结果显示,AUC0-τ无显著性差异(P＞0.05),表明两制剂生物等效.     

盐酸二甲双胍片生物等效性及药物动力学研究

采用随机交叉、自身对照实验设计,比较了两种盐酸二甲双胍片在18名健康男性受试者体内的药动学情况.血药浓度采用高效液相色谱法测定.方差分析结果表明,两者主要药动学参数无显著差别,双单侧t检验表明两者生物等效.     

Confidence Interval Criteria for Assessment of Dose Proportionality

Purpose. The aim of this work was a pragmatic, statistically sound and clinically relevant approach to dose-proportionality analyses that is compatible with common study designs. Methods. Statistical estimation is used to derive a (1-)% confidence interval (CI) for the ratio of dose-normalized, geometric mean values (R_dnm) of a pharmacokinetic variable (PK). An acceptance interval for R_dnm defining the clinically relevant, dose-proportional region is established a priori. Proportionality is declared if the CI for R_dnm is completely contained within the critical region. The approach is illustrated with mixed-effects models based on a power function of the form PK = ₀ Dose¹; however, the logic holds for other functional forms. Results. It was observed that the dose-proportional region delineated by a power model depends only on the dose ratio. Furthermore, a dose ratio (₁) can be calculated such that the CI lies entirely within the pre-specified critical region. A larger ratio (₂) may exist such that the CI lies completely outside that region. The approach supports inferences about the PK response that are not constrained to the exact dose levels studied. Conclusion. The proposed method enhances the information from a clinical dose-proportionality study and helps to standardize decision rules.     

The Role of Metabolites in Bioequivalency Assessment. III. Highly Variable Drugs with Linear Kinetics and First-Pass Effect

Purpose. Simulated pharmacokinetic (PK) studies were done to determine the effect of intrinsic clearance (CL_INT) on the probability of meeting bioequivalence criteria for extent (AUC) and rate (Cmax) of drug absorption when the absorption rate and fraction absorbed (F) were formulated either to be equivalent or to differ by 25%. Methods. Simulated PK studies were done using a linear first-pass model with CL_INT values ranging from 15 L/HR to 900 L/HR. Test/Reference absorption rate constants (Ka) and fraction absorbed (Fa) ratios of 1.0 or 1.25 were used for all simulations. The impact of the value of CL_INT and its intrasubject variation upon the probability of concluding bioequivalence at the two different Ka and F ratios was studied. Additionally, the effect of fraction metabolized i.v., (Fm) on the probabilities of concluding equivalence was studied at values of 0.25 and 0.75. Results. When CL_INT values were raised above those for liver blood flow, the frequency of trials in which bioequivalence was correctly declared decreased when parent AUC was used as a bioequivalence criterion. Only when CL_INT exceeded liver blood flow did the metabolite become important in assessing extent of absorption. Conclusions. The Cmax for the parent drug provided the most accurate assessment of bioequivalence. The Cmax for the metabolite was insensitive to changes related to rate of input, and when CL_INT exceeded liver blood flow, evaluation of the metabolite Cmax data may lead to a conclusion of bioequivalence for products that were not.     

Pharmacokinetics and bioequivalence of a combined oral formulation of eniluracil, an inactivator of dihydropyrimidine dehydrogenase, and 5-fluorouracil in patients with advanced solid malignancies

Background:This study was performed to evaluate thepharmacokinetics, bioequivalence, and feasibility of a combined oralformulation of 5-flurouracil (5-FU) and eniluracil (Glaxo Wellcome Inc.,Research Triangle Park, North Carolina), an inactivator of dihydropyrimidinedehydrogenase (DPD). The rationale for developing a combined eniluracil/5-FUformulation oral dosing form is to simplify treatment with these agents, whichhas been performed using separate dosing forms, and decrease the probabilityof severe toxicity and/or suboptimal therapeutic results caused byinadvertently high or conversely insufficient 5-FU dosing. Patients and methods:The trial was a randomized, three-waycrossover bioequivalence study of three oral dosing forms of eniluracil/5-FUtablets in adults with solid malignancies. Each period consisted of two daysof treatment and a five- to seven-day washout phase. Eniluracil at a dose of20 mg, which results in maximal DPD inactivation, was administered twice dailyon the first day and in the evening on the second day of each of the threetreatments. On the morning of the second day, all patients received a totaleniluracil dose of 20 mg orally and a total 5-FU dose of 2 mg orally as eitherseparate tablets (treatment A) or combined eniluracil/5-FU tablets in twodifferent strengths (2 tablets of eniluracil/5-FU at a strength (mg/mg) of10/1 (treatment B) or 8 tablets at a strength of 2.5/0.25 (treatment C)). Thepharmacokinetics of plasma 5-FU, eniluracil, and uracil, and the urinaryexcretion of eniluracil, 5-FU, uracil, and -fluoro--alanine (FBAL),were studied. To determine the bioequivalence of the combined eniluracil/5-FUdosing forms compared to the separate tablets, an analysis of variance onpharmacokinetic parameters reflecting eniluracil and 5-FU exposure wasperformed. Results:Thirty-nine patients with advanced solid malignancies hadcomplete pharmacokinetic studies performed during treatments A, B, and C. Thepharmacokinetics of eniluracil and 5-FU were similar among the three types oftreatment. Both strengths of the combined eniluracil/5-FU dosing form and theseparate dosing forms were bioequivalent. Mean values for terminal half-life,systemic clearance, and apparent volume of distribution for oral 5-FU duringtreatments A/B/C were 5.5/5.6/5.6 hours, 6.6/6.6/6.5 liters/hour, and50.7/51.5/50.0 liters, respectively. The intersubject coefficient of variationfor pharmacokinetic variables reflecting 5-FU exposure and clearance intreatments ranged from 23% to 33%. The urinary excretion ofunchanged 5-FU over 24 hours following treatments A, B, and C averaged52.2%, 56.1%, and 50.8% of the administered dose of 5-FU,respectively. Parameters reflecting DPD inhibition, including plasma uraciland urinary FBAL excretion following treatments A, B, and C were similar.Toxicity was generally mild and similar following all three types oftreatments. Conclusions:The pharmacokinetics of 5-FU and eniluracil weresimilar and met bioequivalence criteria following treatment with the separateoral formulations of 5-FU and eniluracil and two strengths of the combinedformulation. The availability of a combined eniluracil/5-FU oral dosing formwill likely simplify dosing and decrease the probability of severe toxicityor suboptimal therapeutic results caused by an inadvertent 5-FU overdose orinsufficient 5-FU dosing in the case of separate oral formulations, therebyenhancing the overall feasibility and therapeutic index of oral 5-FU therapy.     

萘普生钠片的人体生物等效性研究

 目的：通过交叉试验比较两种萘普生钠制剂的生物等效性。方法：以8名男性志愿受试者按交叉试验方案以高效液相色谱法测定血浓度。进行两种制剂一次口服给药300 mg的药物动力学和生物利用度比较试验。结果：两种片剂药物动力学参数无显著差异。试验片的相对生物利用度为112.2%。结论：在8名受试者交叉试验证明两种制剂萘普生钠片生物利用度相当，证明两种片剂生物等效。     

盐酸特比萘芬片人体药动学和生物等效性研究

目的 研究盐酸特比萘芬片的人体药动学,并对试验制剂盐酸特比萘芬片和参比制剂盐酸特比萘芬片(兰美抒)的生物等效性进行评价.方法 按照两制剂两周期随机交叉设计,19名男性健康志愿者单剂量口服试验制剂盐酸特比萘芬片和参比制剂盐酸特比萘芬片(兰美抒)250 mg.采用HPLC-UV法测定血浆盐酸特比萘芬片浓度,并进行统计学分析.结果 单剂量口服250mg盐酸特比萘芬片试验和参比制剂,测定得主要药动学参数如下:Cmax分别为(1.66±0.62)μg·mL-1和(1.55±0.66)μg·mL-1,Tmax分别为(1.5±0.7)h和(1.4±0.6)h,t1/2(Kel)分别为(12.65±3.07)h和(14.24±3.65)h,MRT分别为(10.21±3.13)h和(11.56±3.62)h,AUC0-48分别为(5.98±2.45)μg·h·mL-1和(6.76±3.14)μg·h·mL-1,AUC0-∞分别为(6.32±2.58)μg·h·mL-1和(7.20±3.27)μg·h·mL-1.按AUC0-48估算,受试制剂的人体平均相对生物利用度为(95.1±22.5)%,按AUC0-∞估算,平均相对生物利用度为(93.9±21.6)%.结论 两制剂主要药动学参数经对数转换后进行方差分析及双单侧t检验,并计算90%置信区间,表明两种制剂生物等效.     

磷酸奥司他韦干混悬剂的人体药动学与生物等效性

目的:研究磷酸奥司他韦干混悬剂在健康受试者的人体药动学和生物等效性。方法:78例受试者分别空腹和餐后口服75 mg受试制剂或参比制剂。采用高效液相色谱-串联质谱(HPLC-MS/MS)检测奥司他韦和奥司他韦酸的全血浓度,用WinNonlin 8.2软件计算药动学参数,评价两制剂生物等效性。结果:空腹试验受试制剂和参比制剂的奥司他韦C_max、AUC_0-t、AUC_0-∞分别为(52.07±23.44)和(50.54±16.09)ng·mL^-1、(150.8±32.0)和(153.6±29.3)h·ng·mL^-1、(154.2±32.2)和(157.8±30.9)h·ng·mL^-1;奥司他韦羧酸盐C_max、AUC_0-t、AUC_0-∞分别为(259.66±42.65)和(267.10±44.06)ng·mL^-1、(3 235.1±549.9)和(3 321.6±567.5)h·...     

UHPLC-MS/MS测定人血浆中依匹哌唑浓度及其生物等效性研究

目的 建立简便灵敏的超高效液相色谱-串联质谱法(ultra performance liquid chromatography tandem mass spectrometry,UHPLC-MS/MS)测定人血浆中依匹哌唑浓度,并应用于2种片剂的生物等效性研究。方法 采用Waters Acquity UPLC BEH C₁₈色谱柱(2.1 mm×50 mm,1.7μm),以0.1%甲酸水溶液(A)-乙腈-甲醇(50∶50,含0.1%甲酸)(B)梯度洗脱,流速0.4 mL·min^–1,进样量为2μL,柱温40℃,以正离子MRM模式测定依匹哌唑(m/z 434.2→273.2)的浓度,依匹哌唑-d₈(m/z 442.4→281.3)作为内标,离子源为ESI源。血浆样本加入内标,加入甲醇后进行蛋白沉淀,取上清液稀释后进样检测。结果 依匹哌唑在0.2～50 ng·mL^–1呈线性关系,定量下限为0.2 ng·mL^–1,质控样品批内、批间精密度CV≤5.0%,准确度相对偏差在标示值–1.7...     

Exposure-response analysis reveals that clinically important toxicity difference can exist between bioequivalent carbamazepine tablets

AIMS

To assess whether, using the current regulatory criteria, therapeutically important differences can exist between bioequivalent carbamazepine (CBZ) tablets. A secondary goal was to demonstrate quantitatively the relationship between the risk of neurological adverse effects to orally ingested CBZ and the rate of absorption.

METHODS

Results of a bioequivalence study by Olling et al. (Biopharm Drug Dispos 1999; 20: 19–28) were reanalysed. Following an exploratory data analysis step, a mixed-effect pharmacokinetic–pharmacodynamic (PK–PD) model was built to describe the dependence of adverse events on the CBZ concentration.

RESULTS

Rapid development of tolerance was demonstrated for most neurological adverse effects, with a characteristic half-life of 02.29 h and an initial EC50 of 2.33 mg l⁻¹. The resulting tolerance PK–PD model was characterized further using the tools and terminology of sensitivity analysis. It was demonstrated that the maximum concentration (C_max) exhibits poor PK and PD sensitivities, and that clinically significant differences can exist between formulations which otherwise comply with the bioequivalence requirements. In contrast, another PK metric, the partial AUC, was a much better marker of the early neurological adverse events observable during the absorption phase of the drug.

CONCLUSIONS

In clinical and regulatory considerations, the development of acute tolerance for adverse effects of CBZ must be taken into account. Partial AUC reflects more sensitively the risk of adverse events than C_max. Instead of the current trend of tightening of the bioequivalence criteria for narrow therapeutic index drugs, the use of alternative, more sensitive PK metrics is proposed.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• The occurrence of central nervous system-related adverse effects has been apparently related to the absorption rate of carbamazepine (CBZ).
• However, the differing absorption rate metrics of four carbamazepine formulations in a bioequivalence study were unclearly associated with the incidence of adverse effects.

WHAT THIS STUDY ADDS

• The relationship between the incidence of most neurological adverse effects and the absorption rate of CBZ was quantitatively established.
• A mixed-effect PK–PD model demonstrated the rapid development of acute tolerance to these effects.
• Characterization of PD and PK–PD sensitivities showed that clinically significant differences in toxicity can exist between bioequivalent CBZ formulations.