Clinical assessment of theophylline absorption from Theolair-SR and two other sustained-release formulations relative to a conventional formulation

In this single dose study with 8 subjects, the rate and extent of theophylline absorption from 3 sustained-release formulations (Theolair-SR tablet, Slo-phyllin Gyrocaps, and an experimental SR tablet) were compared to absorption from a conventional formulation (Theolair tablet) that has been shown to provide both prompt and complete absorption. Plasma theophylline level versus time profiles show that the rate of absorption from all 3 sustained-release formulations is slower than from the conventional tablet. In addition, the higher plasma levels at later times and the slower apparent plasma elimination rate of theophylline following the Theolair-SR tablet as compared to the conventional Theolair tablet indicate that drug absorption continues over a more prolonged period of time. Plasma AUC data indicate, with good assurance, that the extent of theophylline absorption is essentially complete from all 3 sustained-release formulations when compared to data for the conventional tablet. Statistical analyses with plasma AUC data indicate that the Theolair-SR tablet should provide both reliable and complete drug absorption. Projected plasma drug levels for multiple dosage regimens (simulated on the basis of the single dose data from this study) demonstrate that, even with a twice daily dosage regimen, the Theolair-SR tablet has acceptable sustained-release characteristics relative to the conventional Theolair tablet with 4 daily doses, and that the sustained-release properties compare favorably with those of Slo-phyllin Gyrocaps.     

Bioavailability of indomethacin tablets in men volunteers

Indomethacin bioavailability was compared in 22 healthy men who received two tablet dosage formulations and a capsule formulation of indomethacin in a three-way crossover study. In each study period, 50 mg of the indomethacin formulation (25-mg or 50-mg tablets or 50-mg capsules) was administered as a single dose to fasting subjects. Thirteen blood samples were collected at intervals over 24 hours after each dose. Urine samples were collected for 12 hours before each dose and 48 hours after each dose. Serum indomethacin concentrations were measured by a gas chromatographic procedure. The extent of indomethacin absorption for the two tablet formulations was not significantly different from that for the reference capsule. A trend toward earlier and higher peak serum concentrations with the capsule was observed. There was less than 20% difference in mean values for area under the concentration-time curve (AUC) for the three formulations. More than 75% of the subjects had serum concentrations falling between 75 and 125% of the mean serum concentrations. The extent of absorption of indomethacin from the two tablet formulations was similar to that from the capsule.     

甘氨酸茶碱钠缓释片与普通片药物动力学对比

采用一步液液提取反相高效液相色谱法对甘氨酸茶碱钠缓释片 (受试制剂 )与普通片 (参比制剂 )在人体内药物动力学行为进行了对比检测 ,绘制了 12名健康男性志愿受试者分别单剂量和多剂量随机交叉口服上述两种制剂后的茶碱血浆浓度 时间曲线并计算主要的药动学参数 .经统计检验 ,两种制剂的AUC无显著性差异 .单剂量和多剂量口服甘氨酸茶碱钠缓释片的相对生物利用度分别为 (91.7± 16 .8) %和 (10 7.5± 18.6 ) % .与普通片相比 ,甘氨酸茶碱钠缓释片的Cmax较低 ,而Cmin较高 ,Tmax明显滞后 ,MRT延长 ,血药浓度波动幅度显著减小 ,符合缓释制剂的特点 ,可较为安全地应用于临床 .     

Effect of pH on the in vitro dissolution and in vivo absorption of controlled-release theophylline in dogs

Dogs were used to examine the effect of elevated gastric pH on the absorption of controlled-released theophylline dosage forms with pH-dependent dissolution. In vitro studies showed that a controlled-release theophylline tablet dissolved more rapidly if it was initially exposed to an acidic media. In contrast, a controlled-release theophylline beaded capsule was slightly more rapidly dissolved in the absence of an initial exposure to an acidic media. Gastric pH was increased from 0.5-2.5 to 4.5-7.0 in four dogs by using 150-mg ranitidine HCl tablets, administered every 3 h, to induce an achlorhydric condition. Gastric pH was monitored using a Heidelberg capsule. Ranitidine was shown to have no apparent effect on the absorption or clearance of theophylline administered to the dogs as an oral liquid. The mean area under the concentration-time curve to infinity (AUCinf) for the controlled-release theophylline tablet was 21% greater (p less than 0.05) when administered to the four dogs without ranitidine treatment, compared with that following dosing with ranitidine. In contrast, the controlled-release beaded capsule exhibited a 10% greater AUCinf when ranitidine was given concomitantly. In general, ranitidine-induced changes in the in vivo absorption rate parameters for both dosage forms were opposite to those predicted from the in vitro dissolution rates. The results of this study demonstrated that the extent of theophylline absorption from controlled-release dosage forms, in control dogs and dogs with ranitidine-induced achlorhydria, corresponds to the pH-dependent in vitro dissolution properties of the products.     

盐酸环丙沙星缓释胶囊家犬体内生物利用度研究

目的检测盐酸环丙沙星缓释胶囊与普通片在家犬体内的生物利用度。方法样品用乙腈沉淀蛋白 ,然后用氯仿除去杂质。采用反相高效液相色谱法测定家犬体内的盐酸环丙沙星血药浓度。结果受试制剂及参比制剂的cmax分别为 (9 2 0± 2 0 2 )mol·L-1和 (2 2 5 1± 7 2 4)mol·L-1;tmax分别为 (6 0 0± 0 0 )h和 (2 5 0± 0 5 5 )h ;平均滞留时间 (tMR)分别为 (1 2 2 3± 2 92 )h和 (5 66±1 7)h ,2种制剂的AUC无显著性差异 ,相对生物利用度为 (97 1 0± 9 61 ) %。结论经统计学检验 ,受试制剂具有明显的缓释特征 ,2种制剂具有生物等效性 ,盐酸环丙沙星缓释胶囊体内吸收百分数与体外累积释放百分数相关性分析结果表明两者具有显著的相关性 (P <0 0 1 )。     

Pharmacokinetic evaluation in dogs of theophylline in a novel zero-order release core-in-cup tablet

A new core-in-cup tablet that is manufactured from a novel adjustable punch, has been formulated and evaluated for its ability to release with subsequent absorption of theophylline via a zero-order rate of absorption. The core-in-cup tablets were compared with core only tablets and immediate release capsules. Pharmacokinetic parameters used to test the effectiveness of the formulations included, elimination rate, rate and kinetic order of absorption, relative availability as compared with an immediate release capsule of pure theophylline, and percentage area under the curve fluctuation (%AUCF) at steady state. The correlation coefficient, Akaike's information criterion (AIC) and the F -ratio probability were used to test the applicability of a zero-order, first-order, or square root of time model, for the rate of release of theophylline from the core-in-cup and core only tablets. The zero-order rate model was most applicable to the core-in-cup tablet, whereas the square root of time release model was most applicable to the core only tablet. The average %AUCF for the core-in-cup tablet was 9.26±3.15 while that for the core only tablet was 16.19±2.37 (p =0.0545). The results of this study suggest that the core-in-cup tablet is a versatile zero-order release rate dosage form that are simple to produce. © 1998 John Wiley & Sons, Ltd.     

Influence of food on the absorption of theophylline administered in the form of sustained release tablet and microgranules

Two sustained-release formulations of theophylline, tablets (T) and microgranules (MG) forms, were administered in a randomized order to 8 healthy subjects in fasting or with a high-protein test meal (50 per cent). Blood was collected for 32h post-dose. In fasting subjects, absorption of theophylline was significantly faster for T (tmax 5 h) as compared with MG (tmax 8 h, p less than 0.05), but Cmax and AUC were comparable; intersubject variability was higher with T. Administration of a high-protein test meal with T produced a significant decrease of the zero-order absorption rate constant of theophylline (K omicron 37.8 +/- 9.1 mgh-1 after meal versus 58.8 +/- 13 mgh-1 in fasting, p = 0.01), tmax was doubled to 10 h, and Cmax increased by 25 per cent (6.33 +/- 2.16 mgl-1 versus 5.04 +/- 1.28 mgl-1, p less than 0.02); with MG, tmax were the same (8 h), Cmax were not significantly increased (4.79 +/- 0.84 mgl-1 versus 4.55 +/- 0.67 mgl-1), absorption was delayed (lag-time 1.28 +/- 0.58 h) and the absorption was slightly accelerated (K omicron 50.4 +/- 10.4 mgh-1 versus 42.3 +/- 11.9 mgh-1, NS). For each form bioavailability was not significantly modified by food. This study demonstrated that food rich in protein modifies the absorption rate of theophylline in a sustained-release tablet formulation but is without influence in a pH-independent, sustained-release microgranule formulation.     

2种佐米曲普坦制剂人体生物等效性研究

目的:比较国产佐米曲普坦胶囊与进口佐米曲普坦片剂的人体生物等效性。方法:18名志愿者随机交叉单次口服佐米曲普坦胶囊或片剂10mg后,采用高效液相色谱法测定血药浓度,用3p97软件包计算二者的药动学参数和生物等效性。结果:胶囊与片剂的药-时曲线均为口服吸收一室摸型。t1/2ke分别为(3.72±1.77)、(3.81±1.44)h,tmax分别为(1.42±0.35)、(1.33±0.51)h,Cmax分别为(21.68±8.67)、(21.86±10.38)μg/L,AUC(0～T)分别为(75.94±31.34)、(78.40±28.21)(μg.h)/L。佐米曲普坦胶囊的相对生物利用度为(96.86±13.36)%,经方差分析、双单侧t检验及(1～2α)置信区间法统计分析,2种制剂药动学参数无显著性差异(P>0.05)。结论:佐米曲普坦胶囊与片剂具有生物等效性。     

尼群地平微丸家犬体内药动学研究

目的研究自制尼群地平速释、缓释微丸在家犬体内的药物动力学,并进行相对生物利用度评价。方法分别以尼群地平国产片和日本片为参比制剂,采用高效液相色谱法测定4个制剂的家犬体内血浆药物浓度并绘制平均血药浓度-时间曲线,计算药动学参数并进行方差分析,同时对自制制剂的生物利用度进行了评价。结果尼群地平速释微丸、缓释微丸、国产片和日本片的Tmax依次为0.92±0.14、5.0、1.83±0.29和1.08±0.38h;Cmax依次为187.01±21.23、85.25±13.80、88.31±8.65和160.22±24.34ng.mL-1;AUC0~t依次为665.54±109.07、606.47±130.68、472.44±89.44和659.16±100.05 ng.h.mL-1。以国产片为参比制剂时,自制速释微丸和缓释微丸的相对生物利用度分别为146.92%和135.92%;以日本片为参比制剂时,速释微丸和缓释微丸的相对生物利用度分别为101.04%和91.63%。结论自制速释微丸接近同类产品国外制剂,优于国内制剂;缓释微丸体内作用时间延长,但生物利用度偏低,需进一步改进处方或工艺。     

Bioavailability of hydrocortisone from commercial 20-mg tablets

The relative bioavailability of hydrocortisone was determined from four different 20-mg tablet formulations and one suspension in 15 healthy male volunteers; results were compared with in vitro dissolution rates. Plasma levels of hydrocortisone were determined by a liquid chromatography method developed in this laboratory. Dissolution of the tablet formulations, using the official USP test, varied from 7.8 to 93.8% in 30 min. Similar plasma profiles were obtained from all tablet products, and there were no differences among tablets in the cumulative percentage of drug absorbed. There were no clear trends in any pharmacokinetic parameter values among the tablet dosages, and the four products were considered bioequivalent. The suspension dosage yielded significantly higher plasma levels compared with some of the tablet formulations during the initial 30-min postdose, significantly higher cumulative absorption at 0.5 and 1.0 h compared with one tablet formulation, and significantly higher ka and Cmax, and shorter tmax values, compared with some of the tablets.     

Pharmacokinetic analysis of sustained-release dosage forms of theophylline in humans: comparison of single and multiple dose studies

A pharmacokinetic analysis of two sustained-release dosage forms of theophylline (Theo-Dur and Theotrim) was carried out following single and multiple dose administrations of the two formulations in five healthy subjects. Despite the prolonged absorption after administration of the two sustained-release formulations, theoretical predictions of theophylline steady-state levels following multiple dosages based upon data obtained from the single dose study, correlated with the data of the multiple dose study. This study shows that the recommended dose and dosage regimen of new sustained-release formulations of theophylline can be based upon single dose studies. In the population studied, repetitive doses of 450 mg b.i.d. of Theo-Dur and Theotrim maintain steady-state concentrations of theophylline within the drug's therapeutic window.     

Performance of a modified starch hydrophilic matrix for the sustained release of theophylline in healthy volunteers.

Two experimental formulations of theophylline with a hydrophilic starch matrix were evaluated for their sustained-release characteristics after single administration in healthy human volunteers. Theo-dur was chosen as a reference sustained-release formulation. In a first study, the extent of absorption was similar for a syrup, for Theo-dur, and for the experimental formulation of theophylline with 70% drum-dried corn starch as the sustained-release agent (DDCS-70). The maximal plasma concentration (Cmax) was significantly lower, and the time to reach Cmax as well as the time span during which the plasma concentration was at least 75% of the Cmax were significantly higher for Theo-dur than for the DDCS-70 formulation. A sustained-release profile, as for Theo-dur, was not reached for DDCS-70. In a second study the influence of the starch:drug ratio on the bioavailability was investigated. The decrease in starch content from 70 to 50% of the formulation did not improve the plasma concentration-time profile towards a sustained-release profile.     

Effect of Added Alkalizer and Surfactant on Dissolution and Absorption of the Potassium Salt of a Weakly Basic Poorly Water-Soluble Drug

Telcagepant potassium salt(MK-0974) is an oral calcitonin gene-related peptide receptor inhibitor investigated for the treatment of acute migraine. Under gastric pH conditions, the salt rapidly gels, then converts to an insoluble neutral form that creates an impervious shell on the tablet surface, resulting in a slow and variable release dissolution rate and poor bioavailability. Early attempts to develop a solid dosage form, including solid dispersion and nanosuspension formulations, resulted in low exposures in preclinical studies. Thus, a liquid-filled soft gelatin capsule (SGC) formulation (oblong 20) was used for clinical studies. However, a solid dosage form was desirable for commercialization. The slow dissolution of the tablet formulations was overcome by using a basifying agent, arginine, and inclusion of a nonionic surfactant, poloxamer 407. The combination of arginine and poloxamer in the formulation created a local transient basic microenvironment that promoted the dissolution of the salt and prevented rapid precipitation of the neutral form on the tablet surface to form the gel layer. The tablet formulation achieved fast absorption and comparable exposure to the SGC formulation. The final optimized 280 mg tablet formulation was successfully demonstrated to be bioequivalent to the 300 mg SGC formulation. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:1811–1818, 2014     

Bioavailability of pseudoephedrine from controlled release formulations in the presence of guaifenesin in human volunteers

A multiple-dose bioequivalence study with six healthy human volunteers was conducted. The bioavailability of an experimental controlled release tablet containg pseudoephedrine was compared with a marketed controlled release pseudoephedrine capsule in a three-way crossover study. Plasma samples, collected serially after oral drug administrtion, were analyzed for pseudoephedrine content using a specific HPLC method with UV detection. The bioavailability parameters, area under the concentration-time curve (AUC), maximum plasma concentraton C_max, and time to peak (T_max) were obtained from the plasma concentraton—time data. Additionally, model independent pharmacokinetic parameters were estimated. Analysis of variance of the data revealed no statistically significant differences between the test and the reference formulation. The presence of guaifenesin in the sustained release tablet did not influence pseudoephedrine bioavailability. The relative bioavailability of the tablet dosage form with respect to the capsule was found to be 100.8%. Classical and Westlake 95% confidence limits as well as the two one-sided t test, proposed by Schuirmann, and the Anderson—Hauck power analysis supported the inference that the two formulations demonstrated comparable bioavailability, even in the presence of guaifenesin. Using a non-linear regression program, it was found that the parmacokinetics of pseudoephedrine followed a simple one-compartment disposition model with no lag time. Additionally, an in vitro—in vivo correlation, based on the estimation of cumulative relative fraction absorbed, was developed between the absorption of pseudoephedrine in humans and the in vitro dissolution time.     

Bioequivalence of pyrantel pamoate dosage forms in healthy human subjects

Drugs that are largely restricted to the gastro-intestinal tract (GIT) for their therapeutic efficacy and that are not substantially absorbed into the body are usually inadequately studied in terms of systemic bioavailability. The possibility of systemic effects requires that bioavailabilities be studied to ensure against enhanced toxicity resulting from formulation differences. Pyrantel pamoate falls into this category. High-performance liquid chromatography was employed in this study to determine plasma levels of pyrantel in nine healthy human subjects after administration of tablet and suspension dosage forms. Mean peak plasma concentrations of 37.56 ± 9.37, 35.89 ± 8.94, and 36.22 ± 10.10 ng mL^?1 were obtained following administration of 750 mg pyrantel pamoate in three different formulations. The mean t_max values were 2.02 ± 0.12, 2.05 ± 0.356, and 2.05 ± 0.339 h respectively for the above dosage forms; the respective AUC_0–9 values were 81.01 ± 12.97, 94.59 ± 17.18, and 101.47 ± 19.59 h ng mL^?1. There was no statistically significant difference between the bioavailabilities of the dosage forms tested. Large inter-subject variations were observed. One subject experienced abdominal discomfort and one experienced dizziness. It was not possible to clearly correlate individual variations in absorption with the observed adverse effect because the number of incidents was low (two out of 27 treatments).     

尼群地平缓释胶囊在家犬体内的药动学与相对生物利用度

目的研究尼群地平缓释胶囊在家犬体内的药代动力学与相对生物利用度。方法用高效液相色谱法测定了 6条健康家犬口服尼群地平缓释胶囊 (受试制剂 )和尼群地平普通片 (参比制剂 )后不同时间点血浆中尼群地平的浓度 ,绘制血药浓度 -时间曲线 ,计算药代动力学参数及相对生物利用度。结果受试犬口服含尼群地平 4 0mg的受试制剂和参比制剂后 ,血浆中尼群地平的tmax分别为 (6 1 7± 1 60 )和 (1 4 6± 0 5 1 )h;cmax分别为 (3 4 3 8± 1 2 2 6)和 (45 6 5± 1 0 7 4 )nmol L ;用梯形法计算 ,AUC0～t分别为 (1 93 0 1± 1 0 0 5 1 0 6)和 (1 790 8± 94 2 8)nmol·h L。以AUC计算 ,与参比制剂相比 ,受试制剂中尼群地平的相对生物利用度平均为 (1 1 0 5 9± 2 3 60 ) %。将AUC0～t经对数转换后进行方差分析 ,结果表明 ,受试制剂与参比制剂相比 ,除个体间外 ,周期间与制剂间无显著性差异 (P >0 0 5 ) ,受试制剂AUC0～t的 90 %置信区间为参比制剂的 88 5 4 %～ 1 3 1 93 %。结论尼群地平缓释胶囊与国外普通片相比 ,在犬体内具有更长的作用时间 ,且相对生物利用度相近     

国产罗红霉素胶囊和片剂的药物动力学和生物利用度比较

目的：比较罗红霉素胶囊和片剂的生物利用度和药物动力学。方法：８ 名健康志愿者单剂量口服３００ｍ ｇ 罗红霉素胶囊和片剂,微生物法测定血药浓度。结果：罗红霉素胶囊和片剂的血药浓度－ 时间曲线符合二室模型,Ｃｍ ａｘ 分别为（１０－１４ ±１－６６） 和（１０－０２ ±１－８４）μｇ／ ｍｌ ;Ｔｍ ａｘ 分别为（１－４４ ±０－３２） 和（１－３１ ±０－２６）ｈ ;ＡＵＣ 分别为（７９－８７ ±１６－２２） 和（７３－８６ ±１３－４６）ｈ／（μｇ ·ｍｌ） 。结论：两种制剂药物动力学参数无显著性差异,罗红霉素胶囊和片剂具有生物等效性,胶囊相对于片剂的生物利用度为（１０９ ±１５） ％ 。     

萘哌地尔缓释胶囊在家犬体内的药动学

目的 :研究萘哌地尔缓释胶囊在家犬体内的药动学与生物利用度。方法 :以健康家犬5只为对象 ,采用自身对照方式 ,单剂量分别给予萘哌地尔普通胶囊和缓释胶囊200mg ,血药浓度以高效液相色谱法测定。统计比较普通胶囊与缓释胶囊的生物利用度和药动学参数的差异。结果 :给药后 ,血药浓度变化符合一室模型 ,T1/2 分别为 (3 2±1 1)h、(5 9±0 8)h。普通胶囊的AUC0～∞、Cmax和Tmax 分别为 (3728 1±573 1) (ng·h)/ml、(697 5±94 2)ng/ml和 (1 2±0 59)h ;缓释胶囊的AUC0～∞、Cmax 和Tmax 分别为 (5518 3±391 1) (ng·h)/ml、(468 6±61 3)ng/ml和 (4 0±0 7)h。以普通胶囊为参比制剂 ,缓释胶囊的生物利用度为(149 8±14 4) %。结论 :萘哌地尔缓释胶囊在家犬体内表现出较好的缓释特性 ,其生物利用度明显高于普通胶囊。     

盐酸普萘洛尔缓释片与常释片的生物利用度比较研究

目的：通过双交叉试验证明盐酸普萘洛尔缓释片有缓释作用。方法：用HPLC方法,测定血清中普萘洛尔浓度,进行盐酸普萘洛尔缓释片与常释片的生物利用度比较及峰谷浓度波动研究。结果：12位健康男性受试者一次交叉口服缓释片和常释片(均为40 mg)后的C_max分别为62.4±23.3和95.9±12.6 ng.mL^-1,AUC分别为360.2±80.6和383.5±74.2 ng.h.mL^-1,缓释片相对于常释片的相对生物利用度为95%;12位受试者连续服缓释片和常释片后平均稳态浓度分别为42.2±12.2和32.7±7.1 ng.mL^-1,波动度(DF)分别为0.90±0.35和2.09±0.34。结论：两种制剂具生物等效性,且缓释片比常释片有峰谷浓度差异小、血药浓度波动幅度小的特点。     

Pharmacokinetics of methylphenidate after oral administration of two modified-release formulations in healthy adults

OBJECTIVE: To compare the rate and extent of absorption of DL-threo-methylphenidate (MPH) from two modified-release MPH formulations at their respective recommended starting doses in healthy adult volunteers. DESIGN: Open-label, randomised, crossover, bioavailability study. PARTICIPANTS: Twenty healthy adult male and female volunteers. METHODS: Subjects received single doses of two modified-release formulations of MPH, a 20mg capsule (Ritalin) LA) and an 18 mg tablet (Concerta). A total of 19 plasma samples was collected over 24 hours, and MPH plasma concentrations were determined by liquid chromatography-mass spectrometry (LC-MS/MS). These values were used to calculate standard noncompartmental pharmacokinetic parameters describing the rate (peak concentration and time to peak concentration) and extent (area under the concentration-time curve, AUC) of absorption of the two formulations. The relative bioavailability of the two drugs was assessed using a 90% confidence interval, based on the lower and upper endpoints of the confidence interval for the ratios of the geometric means (log transformed) being within the 0.80-1.25 equivalence criterion. RESULTS: Nineteen subjects, ten male and nine female, aged 21-34 years completed both treatment phases of the study. The Ritalin LA formulation displayed a distinctly biphasic pharmacokinetic profile, with mean initial peak plasma concentration of 7 microg/L at an average of 2.1 hours after administration and a second peak of 9.3 microg/L occurring at 5.6 hours. In contrast, the profile of the Concerta formulation rapidly reached an initial plateau concentration of 3.4 microg/L at 3.3 hours after administration and a second mean plateau concentration of 5.9 microg/L approximately 6 hours after administration. Substantially more MPH was absorbed from Ritalin LA than from Concert over the first 4 hours; the respective AUC(4) values were 18.5 and 9.3 microg x h/L (p < 0.001). The overall extent of absorption of MPH was similar between the two formulations. Oral clearance was identical between the two dosage forms. CONCLUSIONS: The Ritalin LA formulation exhibited more rapid initial absorption and reached significantly higher peak plasma concentrations compared with the Concerta formulation, although the oral bioavailability of MPH was similar between the two formulations. The Ritalin LA capsule demonstrated a distinctly bimodal plasma concentration-time profile. MPH plasma concentrations resulting from Concerta reached a peak at 6 hours. These results indicate that the recommended starting dose of the Ritalin LA 20 mg capsule formulation provides more rapid absorption and higher peak plasma concentrations than the recommended 18 mg starting dose of the Concerta formulation.