4家药厂卡马西平片溶出度和生物利用度考察

目的 对四家药厂卡马西平片溶出度、生物利用度及其相关性考察。方法 按照中国药典2000年版要求，测定四家药厂生产的卡马西平片含量、崩解时限、溶出度；家兔单次口服卡马西平0．1g后，紫外分光光度法测定血药浓度，计算其药代动力学参数Tmax、Cmax、和AUC。结果 3个厂家的卡马西平片含量均符合2000年版中国药典规定，1个厂家溶出度不符合规定；溶出度、Tmax、Cmax、AUC均有显著性差异；体外溶出度参数T50与体内吸收参数Cmax、AUC具有较好的相关性。结论 四家药厂的卡马西平片的质量及生物利用度差异大，同厂不同批号的生物利用度也存在很大差异；体外溶出度与生物利用度均具较好的相关性。     

4家药厂卡马西平片溶出度和生物利用度考察

目的　对四家药厂卡马西平片溶出度、生物利用度及其相关性考察。方法　按照中国药典 2 0 0 0年版要求 ,测定四家药厂生产的卡马西平片含量、崩解时限、溶出度 ;家兔单次口服卡马西平 0 1g后 ,紫外分光光度法测定血药浓度 ,计算其药代动力学参数Tmax、Cmax、和AUC。结果　 3个厂家的卡马西平片含量均符合 2 0 0 0年版中国药典规定 ,1个厂家溶出度不符合规定 ;溶出度、Tmax、Cmax、AUC均有显著性差异 ;体外溶出度参数T50 与体内吸收参数Cmax、AUC具有较好的相关性。结论　四家药厂的卡马西平片的质量及生物利用度差异大 ,同厂不同批号的生物利用度也存在很大差异 ;体外溶出度与生物利用度均具较好的相关性     

卡马西平片体外溶出度与体内吸收相关性

目的：考察卡马西平（ＣＢＺ）片溶出度与体内吸收的相关性。方法：应用ＺＲＳ－４溶出度仪测定卡马西平片的溶出度。４名男性健康志愿性ｐｏ单剂量２００ｍｇＣＢＺ用ＴＤｘ分析仪测定血药浓度，并按照Ｗａｇｎｅｒ－Ｎｅｌｓｏｎ公式计算药物吸收分数。结果：体外溶出度与体内药物吸收分数的相关系数ｒ＝０．９２６１，体外溶出度与体内药物吸收分数的相关系数ｒ＝０．９９７７。结论：ＣＢＺ片体外溶出度与体内吸收有较好的相关性     

吐温-80用于提高卡马西平片的溶出度

吐温－８０用于提高卡马西平片的溶出度庄愉（江苏海安制药厂，海安２２６６００）卡马西平片临床主要用于抗癫痫，其疗效与溶出度有着密切关系［１］。中国药典１９９０年版规定其溶出度应不低于标示量的６５％。用我厂过去一直采用的处方压片，其崩解时限虽然符合规定，...     

不同厂家卡马西平片溶出度考察

目的：对国内５个厂家生产的卡马西平片进行了溶出度考察。方法：按中国的药典１９９５年版溶出度测定法第二法测定卡马西平片的溶出度。结果：提取参数（Ｔ５０,Ｔｄ,ｍ）,并对参数进行相关性研究。结论：各厂产品溶出度参数差异有极显著性（Ｐ〈０．０１）。Ｂ、Ｄ、Ｅ厂生产的卡马西平片溶出度符合中国药典规定,Ａ、Ｃ厂生产的卡马西平片溶 出度不符合规定。     

卡马西平片的质量分析与体内吸收评价

目的:测定卡马西平片的质量与单剂量健康人群口服后的体内生物利用度参数,分析体内外参数的相关性.方法:用荧光偏震免疫法,按正交拉丁方设计,用双盲法,以自身为对照测定卡马西平片在健康人群中口服的代谢情况.结果:测定的6个厂家生产的卡马西平片的质量差异较大,溶出度参数差异显著,硬度无规律;其在健康人群中的代谢呈现多峰现象,体内代谢参数与体外溶出参数不能认为有相关性.结论:不同厂家生产的卡马西平片质量差异大,体外溶出参数作为体内吸收的指标不合理,给药个体化十分必要.     

卡马西平片溶出度方法比较以及溶出曲线评价方法的探讨

目的对3家市售卡马西平片体外溶出度进行比较,为质量控制、溶出度评价方法提供依据。方法通过比较4种不同pH溶出介质中光纤原位药物溶出仪与药典经典方法测定的溶出度曲线,采用f2因子进行溶出曲线的相似性评价。结果采用光纤原位溶出仪测定卡马西平溶出曲线,其方法准确且仪器性能可靠。同一批卡马西平片在不同溶出介质中溶出差异不大;f2相似因子结果证明,不同药厂卡马西平片的质量存在显著性差异,临床用药时应加以注意。结论光纤溶出仪可用于评价固体制剂溶出差异以及内在质量。     

卡马西平片的质量分析与全内吸收评价

目的：测定卡马西平片的质量与单剂量健康人群口服后的体内生物利用度参数,分析体内外参数的相关性。方法：用荧光偏震免疫法,按正交拉丁方设计,用双盲法,以自身为对照测定卡马西平片在健康人群中口服的代谢情况。结果：测定的６个厂家生产的卡马平片的质量差异较大,溶出度参数差异显著,硬度无规律;其在健康人群中的代谢呈多峰现象,体内参数与体外溶出参数不能认为有相关性。结论：不同厂家生产的卡马西平片质量差异大,体外溶出参数作为体内吸收的指标不合理,给药个体化十分必要。     

卡马西平片的体外溶出度考察

本文对３家制药厂的卡马西平片进行了体外溶出度考察。结果显示：福州Ａ厂产品溶出最快，其溶出量符合《中国药典》１９９０年版规定，无锡Ｂ厂和广东Ｃ厂均不符合药典规定，其中Ｃ厂最慢。     

尼群地平胶丸的研制

采用聚乙二醇４００制备了尼群地平软胶丸,其体外溶出度高于市售片剂。９名健康受试者交叉口服胶丸剂和片剂,胶丸剂的达峰时间（Ｔｍａｘ）提前,峰浓度（Ｃｍａｘ）增高,药时曲线下面积（ＡＵＣ）值增加,经统计学分析,两制剂的生物利用度有显著性差异。     

In vitro and in vivo characteristics of some commercial phenobarbital tablets

Using an incompletely randomized crossover study design, the oral bioavailability characteristics of 7 different brands of phenobarbital tablets, USP, 100 mg was investigated in 5 adult, male volunteers. From plasma drug concentration-time data, best estimates for the bioavailability parameters of peak plasma phenobarbital concentration (Cmax) and time to peak concentration (tmax) were obtained by curve fitting and area under the plasma drug concentration-time curve (AUC) computed with the trapezoid rule. No significant difference in Cmax or normalized AUC was seen for the 7 products investigated. Additionally, a difference in tmax was observed between 2 preparations (A and E) only (p less than or equal to 0.05). All drug products met USP requirements for weight variation and tablet disintegration and all but one product (D) exhibited reasonably good and similar dissolution characteristics in simulated gastric fluid. No correlation between various in vitro dissolution parameters and in vivo bioavailability of phenobarbital could be found for the 7 phenobarbital products studied.     

Oral bioavailability of griseofulvin from aged griseofulvin:lipid coprecipitates: in vivo studies in rats.

The bioavailabilities of aged coprecipitates of griseofulvin (Gris), dimyristoylphosphatidylcholine (DMPC), or egg phosphatidylcholine (EPC) and cholesterol (CHOL) in rats and correlations with their in vitro dissolution behaviors were determined. In vivo absorption studies of Gris:DMPC (4:1, w/w) or Gris:DMPC:CHOL [4:1(1:0.33 mole ratio)] coprecipitates yielded evidence of a 40% increase in the peak concentration in plasma (Cmax) and a 2.5- to 3-fold decrease in the time to reach Cmax (tmax), compared with those obtained with micronized Gris but a statistically unchanged area under the concentration in plasma--time curve (AUC) when 1-day-aged samples at equivalent doses were used. On the other hand, a 10% decrease in the AUC, a 20% increase in the Cmax, and a three- to fourfold decrease in the tmax were observed for the same formulations aged for 90 days. In comparison, the Cmax produced by the 1-day-aged Gris:EPC:CHOL [4:1(1:0.33 mole ratio)] coprecipitate was the same as that produced by micronized Gris, but the tmax and the AUC were significantly lower; the Cmax produced by the 90-day-aged coprecipitate was 30% higher than that produced by micronized Gris, but the tmax and the AUC remained unchanged. The Gris concentrations after 5 and 30 min (dissolution parameters) and the percent dissolution efficiency also showed excellent correlations with the concentration in plasma after 1 h, the Cmax, and the AUC (in vivo parameters) for all formulations, but the individual in vitro parameters showed poor correlations with the AUC results.(ABSTRACT TRUNCATED AT 250 WORDS)     

不同厂家司帕沙星片体外溶出度比较

目的考察4厂家司帕沙星片的体外溶出度,为临床用药提供参考。方法采用转篮法进行体外溶出度实验,用紫外分光光度法进行含量测定,计算其累积溶出百分率,并以威布尔方程拟合溶出参数。结果不同厂家的司帕沙星片体外溶出度均符合2005年版《中国药典》相关规定,但各厂家T50,Td值间均有显著性差异。结论不同厂家司帕沙星片溶出参数存在差异,临床选用应加以注意。     

Bioavailability studies of theophylline ethylcellulose microcapsules prepared by using ethylene-vinyl acetate copolymer as a coacervation-inducing agent

The bioavailability of theophylline microcapsules prepared by using ethylene-vinyl acetate (EVA) copolymer as a coacervation-inducing agent was studied in rats. The dissolution rate of the microcapsules was determined by the rotating-basket and rotating-bottle methods. The higher the concentration of EVA copolymer used, the more sustained was the release of theophylline from the microcapsules. The mean maximum serum levels (Cmax) and time to maximum serum levels (tmax) were not significantly different for theophylline microcapsules prepared by a lower concentration of EVA copolymer (0 and 0.83%, respectively), compared with those for theophylline powder; whereas a significant difference was found when the higher concentration of EVA copolymer was used (greater than 1.7%). With regards to the area-under-the-curve (AUC) value, there was no significant difference between the theophylline powder and theophylline microcapsules. The elimination kinetics and the corresponding half-life (t1/2) were significantly different when the concentration of EVA copolymer was greater than 3.3%. From the above results, it is evident that theophylline microcapsules prepared by using 3.3 and 5.0% EVA copolymer as the coacervation-inducing agent may act as sustained-release dosage forms. The correlation between the dissolution rate in vitro and the bioavailability in rats for theophylline microcapsules was investigated. The mean Cmax and tmax correlated well with the time taken to release 75% of the drug in vitro (t 75%); however, the mean AUC showed no valid correlation with t 75%. This implies that the dissolution rate correlated better with the rate of absorption (Cmax, tmax) than with the extent of absorption (AUC).(ABSTRACT TRUNCATED AT 250 WORDS)     

In vitro dissolution and in vivo bioavailability of commercial levothyroxine sodium tablets in the hypothyroid dog model

The objective of this study was to determine whether a correlation exists between the rate of in vitro dissolution and bioavailability of levothyroxine sodium (T4) tablets. Dissolution versus time profiles for Synthroid, the Flint brand of levothyroxine sodium, and two competitors' tablets (brands A and B) were generated using an official dissolution apparatus (USP), and 0.05 M phosphate buffer (pH 7.4) as the medium. These tablets were also utilized in single-dose crossover bioavailability studies in the hypothyroid dog model (n = 6). The average areas under the serum T4 concentration versus time curve from 0 to 8 h (AUC) for Synthroid, brand A, and brand B were 8.22, 6.32, and 8.70 ng-h/mL per dose (micrograms per kg body weight), respectively. Respective peak serum concentrations (Cmax) for each tablet formulation were 1.26, 1.07, and 1.36 ng/mL per dose. The corresponding dissolution rates, expressed as t50%, were 20.5, 3.06, and 14.1 min, respectively. Data analysis indicated no correlation between dissolution kinetic parameters and the bioavailability parameters AUC and Cmax. However, a linear relationship was observed between dissolution kinetics and both the time to reach maximal serum concentration (tmax) and the observed absorption rate constant (ka).     

In vitro dissolution and in vivo oral absorption of methylphenidate from a bimodal release formulation in healthy volunteers

PURPOSE: The objective of this study was to evaluate the in vitro dissolution and in vivo absorption of D,L-threo-methylphenidate (MPH) from a novel bimodal release formulation (Ritalin LA capsule) compared with an immediate-release formulation (Ritalin IR tablet) in healthy volunteers. METHODS: The bimodal release formulation contains 50% of the dose in the immediate-release (IR) beads and 50% in polymethacrylate-coated, delayed-release (DR) beads. To better understand the impact of dissolution from the DR beads on oral absorption of MPH, three Ritalin LA formulations with different dissolution profiles for the DR beads (referred to as slow-, medium and fast-release formulations) were prepared, and tested together with the immediate-release formulation in 18 healthy male and female volunteers after a single oral dose under fasted conditions. The rate and extent of oral absorption of MPH were evaluated based on the overall Cmax, tmax and AUC values, as well as the Cmax, tmax and AUC values for each individual peak of the bimodal plasma concentration-time profile. The in vivo absorption-time profile was also examined by deconvolution. RESULTS: All three Ritalin LA formulations demonstrated similar bimodal plasma concentration-time profiles with two peak concentrations observed at approximately 2 and approximately 6 h post dose, mimicking that of Ritalin IR tablets given 4 h apart. Deconvolution results showed that the absorption of MPH was biphasic, with a rapid absorption phase between 0 to approximately 2 h, and a somewhat slower second absorption between approximately 3-6 h, consistent with the in vitro bimodal release characteristics of Ritalin LA formulation. The three Ritalin LA formulations were bioequivalent to one another based on the overall Cmax and AUC values and the corresponding values describing the first and second peaks, although their in vitro dissolution profiles for the DR beads were different. Compared with Ritalin IR, the Ritalin LA formulation demonstrated a similar rate of absorption for the first peak, a lower second Cmax and a higher trough concentration between peaks, as well as similar overall plasma AUC. CONCLUSIONS: Following a single oral drug administration, Ritalin LA demonstrated a two-peak plasma concentration-time profile, similar to that of the IR formulation given 4 h apart, but with less fluctuation in the plasma concentration-time profile. The in vivo biphasic absorption of MPH appeared to be well correlated with the bimodal dissolution characteristics of this new Ritalin LA formulation, and some changes in the dissolution profiles for the DR beads appeared not to affect the overall bioavailability of MPH in humans.     

Preparation and evaluation of press-coated aminophylline tablet using crystalline cellulose and polyethylene glycol in the outer shell for timed-release dosage forms

In an attempt to achieve chronopharmacotherapy for asthma, press-coated tablets (250 mg), which contained aminophylline in the core tablet in the form of low-substituted hydroxypropylcellulose (L-HPC) and coated with crystalline cellulose (PH-102) and polyethylene glycol (PEG) at various molecular weights and mixing ratios in the amounts of PH-102 and PEG as the outer shell (press-coating material), were prepared (chronopharmaceutics). Their applicability as timed-release (delayed-release) tablets with a lag time of disintegration and a subsequent rapid drug release phase was investigated. Various types of press-coated tablets were prepared using a tableting machine, and their aminophylline dissolution profiles were evaluated by the JP paddle method. Tablets with the timed-release characteristics could be prepared, and the lag time of disintegration was prolonged as the molecular weight and the amount of PEG, for example PEG 500,000, in the outer shell were increased. The lag time of disintegration could be controlled by the above-mentioned method, however, the pH of the medium had no effect on disintegration of the tablet and dissolution behavior of theophylline. The press-coated tablet (core tablet:aminophylline 50 mg, L-HPC and PEG 6000; outer shell:PH-102:PEG = 8:2 200 mg) with the timed-release characteristics was administered orally to rabbits for an in vivo test. Theophylline was first detected in plasma more than 2 h after administration; thus, this tablet showed a timed-release characteristics in the gastrointestinal tract. The time (tmax) required to reach the maximum plasma theophylline concentration (Cmax) observed after administration of the press-coated tablet was significantly (p < 0.05) delayed compared with that observed after administration of aminophylline solution in the control experiment. However, there was no difference in Cmax and area under the plasma theophylline concentration-time curve (AUC0-->24) between the press-coated tablet and aminophylline solution. These results suggest that the press-coated aminophylline tablet (with the timed-release characteristic) offers a promising forms of theophylline chronotherapy for asthma.     

Bioequivalence of two oral ciprofloxacin tablets formulations

The relative bioavailability of a new 750 mg tablet formulation of ciprofloxacin (test formulation supplied by Dr. August Wolff GmbH and Co., Germany) was compared with that of Ciprobay tablets 750 mg (reference formulation from Bayer Vital GmbH and Co., Germany). Twenty-four healthy volunteers (12 male and 12 female) were included in this single-dose, 2-sequence, crossover randomized study. Blood samples were obtained prior to dosing and at 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 18, 24 and 30 hours after drug administration. Plasma concentrations of ciprofloxacin were determined by HPLC. No differences were found when the in vitro dissolution profiles of both formulations were compared. The pharmacokinetic parameters AUC(0-t), AUC(0-infinity), Cmax and Cmax/AUC(0-infinity) were tested for bioequivalence after log-transformation of data, and ratios of tmax were evaluated nonparametrically. The parametric analysis revealed the following mean values for the test/reference ratios (90% standard confidence intervals in parenthesis (ln-transformed data): 1.01 (0.95-1.07) for AUC(0-t), 0.99 (0.93-1.05) for AUC(0-infinity), 1.05 (0.97-1.14) for Cmax and 1.06 (0.97-1.15) for Cmax/AUC(0-infinity). The nonparametric confidence interval for tmax was 0.77-1.15. All parameters showed bioequivalence between both formulations as their confidence intervals were within the bioequivalence acceptable range of 0.80-1.25 limits; the 90% confidence interval for tmax slightly exceeded limits of bioequivalence. We conclude that both formulations show bioequivalence for both the rate and the extent of absorption.     

Pharmacokinetics and bioequivalence evaluation of 2 levosulpiride preparations after a single oral dose in healthy male Korean volunteers

OBJECTIVE: To evaluate the bioequivalence of a single oral 25 mg dose of 2 levosulpiride preparations in healthy male Korean volunteers. SUBJECTS, MATERIALS AND METHODS: The study was conducted as a randomized, 2-period crossover design in 28 healthy male Korean volunteers who received a single oral dose of 25 mg levosulpiride tablet in each study period. There was a 6-day washout period between the doses. Serum concentrations of levosulpiride up to 36 hours after the administration were determined using a validated HPLC method with fluorescence detection. In addition, in vitro dissolution profiles of both preparations were examined. The pharmacokinetic parameters such as AUC(0-t) (the area under the curve from zero to the time), AUC(0-infinity) (the area under the curve from zero to infinity), Cmax (maximum serum concentration), tmax (time to reach Cmax) and t1/2 (terminal half-life) were analyzed by non-compartmental analysis, and the analysis of variance (ANOVA) was carried out using logarithmically transformed AUC(0-t), AUC(0-infinity) and Cmax, and untransformed Tmax. RESULTS: In vitro dissolution profiles were similar by calculating similarity factor (f2 = 67.73). There were no significant differences between the 2 preparations in AUC(0-t), AUC(0-infinity) and Cmax. The point estimates (90% confidence intervals) for AUC(0-t), AUC(0-infinity) and Cmax were 1.085 (1.003-1.173), 1.069 (0.991-1.153) and 1.075 (0.954 to 1.210), respectively, satisfying the bioequivalence criteria of 0.80-1.25 as proposed by the US FDA and the Korean legislation. No statistically significant difference was found for tmax and t1/2 values. CONCLUSION: From the results of the present study, it is indicated that the 2 preparations of levosulpiride are bioequivalent and it can be assumed that they are therapeutically equivalent and exchangeable in clinical practice.