In Vitro System to Evaluate Oral Absorption of Poorly Water-Soluble Drugs: Simultaneous Analysis on Dissolution and Permeation of Drugs

Purpose. The aim of the present work was to develop a new in vitro system to evaluate oral absorption of poorly water-soluble drugs by utilizing Caco-2 monolayers. Methods. Caco-2 monolayer was mounted between side-by-side chambers, which enabled the simultaneous assay of dissolution and permeation of drugs (dissolution/permeation system; D/P system). Apical and basal sides of the chamber were filled with buffer solutions. Drugs were applied to the apical side as powder, suspension, or solution, and then, the permeated amounts into the basal side were monitored for 2 h. At the same time, dissolved amounts of drugs at the apical side were detected. The amount of drug applied to the D/P system was based on its in vivo clinical dose. Results. Sodium taurocholate (5 mM, apical side) and bovine serum albumin (4.5% w/v, basal side) increased the permeated amount of poorly water-soluble drugs. Both additives were considered to be effective at mimicking in vivo conditions of intestinal drug absorption. From the correlation between the permeated amount of 13 drugs (% dose/2 h) in the D/P system and their percentage dose absorbed in humans in vivo, this system was found to be useful in evaluating oral absorption of poorly water-soluble drugs. Conclusions. With attempts made to mimic the physiologic conditions of the human GI tract, in vivo oral absorption of drugs was quantitatively assessed in the D/P system in vitro. This system is quite useful to predict the oral absorption of poorly water-soluble drugs after administration as solid dosage forms.     

Enhanced Permeation of an Antiemetic Drug from Buccoadhesive Tablets by Using Bile Salts as Permeation Enhancers: Formulation Characterization,In Vitro,and Ex Vivo Studies

Buccal bioadhesive bilayer tablets of prochlorperazine maleate were designed and formulated by using buccoadhesive polymers such as hydroxypropylmethyl cellulose, Carbopol 934P, and sodium alginate. Physicochemical characteristics like the uniformity of weight, hardness, thickness, surface pH, drug content, swelling index, microenvironment pH, in vitro drug release, and in vivo buccoadhesion time of the prepared tablets were found to be dependent on the type and composition of the buccoadhesive materials used. The effect of bile salts on the permeation was studied through porcine buccal mucosa and it was found that out of three bile salts incorporated (sodium glycholate, sodium taurocholate, and sodium deoxycholate), sodium glycholate enhanced the permeation rate of prochlorperazine maleate by an enhancement factor of 1.37.     

A Mechanistic Bayesian Inferential Workflow for Estimation of In Vivo Skin Permeation from In Vitro Measurements

Computational models can play an integral role in the chemical risk assessment of dermatological products. However, a limitation on the ability of mathematical models to extrapolate from in vitro measurements to in human predictions arises from context-dependence: modeling assumptions made in one setting may not carry over to another scenario. Mechanistic models of dermal absorption relate the skin penetration kinetics of permeants to their partitioning and diffusion across elementary sub-compartments of the skin. This endows them with a flexibility through which specific model components can be adjusted to better reflect dermal absorption in contexts that differ from the in vitro setting, while keeping fixed any context-invariant parameters that remain unchanged in the two scenarios. This paper presents a workflow for predicting in vivo dermal absorption by integrating a mechanistic model of skin penetration with in vitro permeation test (IVPT) measurements. A Bayesian approach is adopted to infer a joint posterior distribution of context-invariant model parameters. By populating the model with samples of context-invariant parameters from this distribution and adjusting context-dependent parameters to suit the in vivo setting, simulations of the model yield estimates of the likely range of in vivo dermal absorption given the IVPT data. This workflow is applied to five compounds previously tested in vivo. In each case, the range of in vivo predictions encompassed the range observed experimentally. These studies demonstrate that the proposed workflow enables the derivation of mechanistically derived upper bounds on dermal absorption for the purposes of chemical risk assessment.     

大豆磷脂脂质载体与胆酸盐表面活性剂的体外相互作用

采用旋转薄膜蒸发法结合挤压过滤工艺制备大豆磷脂脂质体,所制得脂质体的平均粒径为217nm,跨距0．838,负染色脂质体经透射电镜观察,呈明显的双层膜圆球型结构。以胆酸钠盐和脱氧胆酸钠盐研究其与脂质体之间的相互作用,将500nm波长处的可见光吸收值评价胆盐-脂质体混悬液的浊度,测定脂质体的粒径变化情况。在胆酸盐加入的初期,由于胆酸盐和脂质体形成混合胶团,致使脂质体的粒径和浊度值稍有增加,进一步加入的胆酸盐使脂质体的粒径和浊度值下降。胆盐和脂质体问的相互作用经历了数个重排现象,使脂质体的粒径发生规律性的变化,这与脂质体的体内稳定性密切相关,也可反映脂质体的载药和释药特性。     

头孢氨苄片的体外释放与人体吸收程度相关性研究

目的：探讨头孢氨苄片体外释放与体内吸收的相关性。方法：以TEVA头孢氨苄片为参比制剂,清远华能头孢氨苄片为受试制剂,用相似因子法比较两种制剂体外溶出曲线相似性,用双周期自身对照交叉试验比较两种制剂人体生物等效性。结果：两种头孢氨苄片的体外溶出曲线相似,体内具有生物等效性。结论：本实验的头孢氨苄片体外释放与人体吸收存在相关。     

In Vitro Dissolution Profile of Water-Insoluble Drug Dosage Forms in the Presence of Surfactants

The determination of the in vitro release profile of water-insoluble drug products requires dissolution media different from those used for water-soluble drug products. Since the relevance of drug dissolution in organic solvents is questionable, we investigated the use of surfactants to determine the dissolution profiles of water-insoluble drug products. In most cases, the drug dissolution rate and extent increased as the surfactant concentration in the aqueous dissolution medium increased. Suitable dissolution profiles were obtained in the presence of sodium lauryl sulfate (SLS) for water-insoluble drug products, such as griseofulvin, carbamazepine, clofibrate, medroxyprogesterone, and cortisone acetate. These findings recommend the use of surfactants for determining the aqueous dissolution of water-insoluble drug products rather than adding organic solvents to the dissolution medium.     

Solubilization and Wetting Effects of Bile Salts on the Dissolution of Steroids

The ability of sodium taurocholate to increase the initial dissolution rate of five steroids was studied in terms of effects on solubility, wetting, and diffusion coefficient. For all compounds, wetting effects predominated over solubilization effects at bile salt concentrations representative of the fasted state. For hydrocortisone, triamcinolone, betamethasone, and dexamethasone, this trend also continued at the higher bile salt concentrations typical of the fed state. Bile salts solubilized these compounds by a factor of two or less, and diffusivity changes were negligible at bile salt concentrations up to 30 mM. For the more lipophilic danazol, the wetting effects were small and of importance only at premicellar levels of bile salt. At higher concentrations, the increase in solubility was the predominant factor. Incorporation into micelles appeared to decrease the diffusivity slightly, but this was important only at bile salts concentrations of 15 mM or higher. In conclusion, it appears that even within a series of structurally related compounds the mechanism by which bile salts mediate increases in dissolution rate can differ considerably.     

Identification of Formulation and Manufacturing Variables That Influence In Vitro Dissolution and In Vivo Bioavailability of Propranolol Hydrochloride Tablets

ABSTRACT

The purpose of this study was to evaluate the effect of formulation and processing changes on the dissolution and bioavailability of propranolol hydrochloride tablets. Directly compressed blends of 6 kg (20,000 units) were prepared by mixing in a 16-qt V blender and tablets were compressed on an instrumented Manesty D3B tablet press. A half-factorial (2^5–1, Resolution V) design was used to study the following variables: filler ratio (lactose/dicalcium phosphate), sodium starch glycolate level, magnesium stearate level, lubricant blend time, and compression force. The levels and ranges of the excipients and processing changes studied represented level 2 or greater changes as indicated by the Scale-up and Post Approval Changes (SUPAC-IR) Guidance. Changes in filler ratio, disintegrant level, and compression force were significant in affecting percent drug released (Q) in 5 min (Q₅) and Q₁₀. However, changes in magnesium stearate level and lubricant blend time did not influence Q₅ and Q₁₀. Hardness was found to be affected by changes in all of the variables studied. Some interaction effects between the variables studied were also found to be significant. To examine the impact of formulation and processing variables on in vivo absorption, three batches were selected for a bioavailability study based on their dissolution profiles. Thirteen subjects received four propranolol treatments (slow-, medium-, and fast-dissolving formulations and Inderal® 80 mg) separated by 1 week washout according to a randomized crossover design. The formulations were found to be bioequivalent with respect to the log C_max and log A UC_0-oo. The results of this study suggest that (i) bioavailability/ bioequivalency studies may not be necessary for propranolol and perhaps other class 1 drugs afer level     

基于渗透速率及溶出曲线初步预测国产氯唑沙宗片的生物等效性

目的：从氯唑沙宗原料药的生物药剂学分类系统(BCS)分类出发,结合氯唑沙宗片的渗透速率及溶出曲线,对国产氯唑沙宗片仿制药与参比制剂的生物等效性进行初步预测。方法：采用人工仿生膜测定氯唑沙宗原料药渗透性,结合其在不同介质中的溶解度,对氯唑沙宗进行BCS分类判断。 选择水、pH 1.2盐酸溶液、pH 4.0磷酸盐缓冲液、pH 6.8磷酸盐缓冲液作为溶出介质,分别采用相似因子(f ² )法、AV值法及非模型依赖多变量置信区间法,对参比制剂与4家企业的国产氯唑沙宗片在不同介质中的溶出曲线进行相似性评价。计算仿制制剂与参比制剂在空腹肠及饱腹肠模拟液溶出介质中的渗透速率及总渗透量的90%置信区间,进行生物等效性预测。结果：氯唑沙宗为BCS Ⅱ类,低溶解度高渗透性药物。体外溶出试验显示国产氯唑沙宗片与参比制剂的相似性较低。渗透速率试验显示,在空腹肠模拟液溶出介质中,与参比制剂渗透速率的90%置信区间分别为101.05%~107.12%、 116.57%~120.13%、99.36%~105.72%、130.17%~139.62%之间,其中3家在80%~125%的生物等效接受标准范围内,1家不在范围内。在饱腹肠模拟液溶出介质中,与参比制剂渗透速率的90%置信区间分别为103.62%~115.49%、116.99%~134.85%、131.70%~141.93%、122.37%~127.23%,其中1家在 80%~125%的生物等效接受标准范围内,3家不在范围内。结论：基于溶出曲线结合渗透速率可在一定程度上较好地模拟药物在人体内的吸收转运过程,该联合应用方法可用于国产氯唑沙宗片与参比制剂生物等效性的初步预测。     

Enhanced Oral Bioavailability of Paclitaxel Formulated in Vitamin E-TPGS Emulsified Nanoparticles of Biodegradable Polymers: In Vitro and In Vivo Studies

This work evaluates the effects of paclitaxel loaded polymeric nanoparticles (NPs) composed of poly(D,L-lactic-co-glycolic acid) (PLGA) with vitamin E TPGS as emulsifier for oral chemotherapy. NPs prepared by a modified solvent extraction/evaporation technique were observed in spherical shape of 200-300 nm diameter with a high drug encapsulation efficiency (EE) of 80.9%. The TPGS-emulsified PLGA NPs formulation of paclitaxel was found of great advantages over that of Taxol®. The in vitro viability experiment showed that the NP formulation could be 1.28,1.38,1.12 times more effective than Taxol® after 24, 48, 72 h incubation with MCF-7 human breast cancer cell line at 2.5 μg/mL paclitaxel concentration. In vivo evaluation confirmed the advantages of the TPGS-emulsified PLGA NP formulation versus Taxol® in promoting oral bioavailability of paclitaxel. Such a NP formulation achieved more than 10 times higher oral bioavailability than Taxol®, which resulted 9.74-fold higher therapeutic effect and 12.56-fold longer sustainable therapeutic time than Taxol®. The present proof-of-concept experimental data proved that the formulation of vitamin E TPGS emulsified PLGA NPs is a promising approach for paclitaxel oral administration. Oral chemotherapy by NPs formulation is feasible. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:3552-3560, 2010     

Topical Formulations Containing Finasteride. Part I: In Vitro Permeation/Penetration Study and In Vivo Pharmacokinetics in Hairless Rat

In hair follicle (Hf) cells, the type-2 5-α-reductase enzyme, implicated in androgenetic alopecia, is selectively inhibited by finasteride (FNS). Because an effective topical formulation to deliver FNS to Hf is currently unavailable, this investigation aimed at evaluating in vitro FNS skin permeation and retention through and into hairless rat and human abdominal skin. Four hydroxypropyl chitosan (HPCH)-based formulations (P-08–012, P-08–016, P-08–063, and P-08–064) and one anhydrous formulation without HPCH (P-10–008) were tested. The pharmacokinetics in plasma and skin after application of P-08–016 or P-10–008 on dorsal rat skin with single and repeated doses was investigated. P-08–016 performed the best in driving FNS to the reticular dermis without producing a high transdermal flux. Neither the in vivo single nor the repeated dose experiments produced plasma levels of FNS and no differences were found between formulations concerning skin retention. No increase in the amount of drug retained in the skin was obtained with the repeated dose experiment. In conclusion, the HPCH-based formulation P-08–016 might represent an alternative to systemic therapy for its ability to promote a cutaneous depot of FNS in the region of hair bulbs, minimizing systemic absorption even after repeated treatments. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:2307–2314, 2014     

Assessing Topical Bioavailability and Bioequivalence: A Comparison of the In vitro Permeation Test and the Vasoconstrictor Assay

Purpose

To compare the sensitivity of a pharmacokinetic assay, the in vitro permeation test (IVPT), with that of a pharmacodynamic assay, the human skin blanching or vasoconstrictor (VC) assay, in assessing the relative bioavailability of topical clobetasol propionate products.

Methods

The percutaneous absorption of clobetasol propionate from five commercial products was measured in vitro using cryopreserved human skin. The pharmacodynamic potency of the same five products was also assessed in vivo using the VC assay, the surrogate method by which regulatory authorities in the United States establish the bioequivalence of generic topical glucocorticoid products.

Results

IVPT found total clobetasol absorption varying ten-fold from highest to lowest product, whereas the VC assay found this same difference was less than two-fold. The coefficient of variation ranged from 78 to 126% in the VC assay, but only 30–43% for IVPT. Statistically, IVPT could separate the 5 products into three groups: 1) ointment, 2) cream and gel, 3) emollient cream and solution). Due to its greater variability as well as saturation of the pharmacodynamic response at higher flux levels, the VC assay found all products except the solution to be equipotent.

Conclusions

IVPT was found to be substantially more sensitive and less variable than the VC assay for assessing clobetasol bioavailability.     

Influence of Tablet Dissolution on Furosemide Bioavailability: A Bioequivalence Study

In order to evaluate the in vitro dissolution and in vivo bioavailability relationship for furosemide, a bioequivalence study was carried out. Furosemide (40 mg) was administered orally to 12 normal volunteers in a 6 × 6 crossover design using six products (five tablets and one solution) obtained from three pharmaceutical companies. Plasma and urine concentrations of furosemide were quantitated by high-performance liquid chromatography (HPLC). Plasma furosemide profiles were analyzed by non-compartmental methods. Compared to the oral solution, all of the formulations exhibited lower peak furosemide concentrations, longer mean residence times, and, in some cases, diminished bioavailability (range, 66–96%). Similar results were obtained when the reference product (a rapidly dissolving tablet) was used as the standard. All of the products failed the 75/75 rule when compared to either reference standard, apparently because of large intersubject variability. The total amount of furosemide excreted in urine could be associated with the percentage drug dissolved (in vitro) at 30 min. The pH 5.6 dissolution medium (compared to pH 4.6) appears to be an appropriate test medium for assuring batch uniformity and bioequivalence of furosemide products.     

甲磺酸培氟沙星分散片的处方研究和体外溶出度考察

目的:优选甲磺酸培氟沙星分散片处方并考察其体外溶出度。方法:对处方中选用的微晶纤维素、交联聚乙烯吡咯烷酮、羧甲基淀粉钠和聚乙烯吡咯烷酮用量进行正交试验;采用紫外分光光度法考察甲磺酸培氟沙星分散片与普通片的溶出度。结果:优选的最佳处方为微晶纤维素20%、交联聚乙烯吡咯烷酮6%、羧甲基淀粉钠5.5%和聚乙烯吡咯烷酮8%。所制分散片在30s内完全崩解,15min时溶出度明显高于普通片。结论:采用本处方及工艺制得的甲磺酸培氟沙星分散片质量可靠,崩解时限短,体外释放度优于普通片。     

Bioavailability of Soil-Bound TCDD: Oral Bioavailability in the Rat

Bioavailability of Soil-Bound TCDD: Oral Bioavailability inthe Rat. SHU, H., PAUSTENBACH, D., MURRAY, F. J., MARPLE, L.,BRUNCK, B., DEI ROSSI, D., TEITELBAUM, P. (1988). Fundam ApplToxicol. 10, 648–654. The implications to the public healthof trace amounts of 2,3,7,8-TCDD in the environment are underevaluation by regulatory agencies in the United States and WesternEurope. One major consideration in such evaluations is the contributionto human exposure via ingestion of TCDD-contaminated soil. An80% figure is under consideration by some regulators for estimatedhuman exposure. A contractor for one agency has, in fact, useda value of 1007% bioavailability for estimating human bioavailability.Several studies have investigated the oral bioavailability ofTCDD from contaminated soil in animals. Most have reported estimatesof 25–50%, although one has reported <0.5 and 85%,depending on the source of the contaminated soil. This paperreports an oral bioavailability of approximately 43% in therat dosed with three environmentally contaminated soil samplesfrom Times Beach, Missouri. This figure did not change significantlyover a 500-fold dose range of 2 to 1450 ng TCDD/kg of body weightfor soil contaminated with approximately 2, 30, or 600 ppb ofTCDD. The relevance of animal oral bioavailability data forthe human remains to be evaluated. However, since regulatoryagencies use animal data for extrapolating to humans, the 43%or 25–50% figure would be more accurate than the 80 or100% estimates.     

Formulation,in Vitro Dissolution,and Ocular Bioavailability of High- and Low-Melting Phenylephrine Oxazolidines

The in vitro dissolution and the relative ocular bioavailability of high- and low-melting phenylephrine oxazolidines (HMP and LMP) from a nonaqueous suspension (silicone fluid) were compared. Stability-indicating HPLC assays were developed for evaluation of the prototype formulations, in which a normal-phase HPLC method was necessary for analysis of PO, while a reverse-phase HPLC method was required for analysis of the primary degradation product, phenylephrine (PE), following its separation from the formulation using a short silica gel column. PO was formulated as an ophthalmic suspension in silicone fluid (20 cs) because of its property of undergoing rapid hydrolysis in aqueous media. An experimental test system for measuring the dissolution characteristics of a water-immiscible multiparticulate suspension was designed to obtain the dissolution profiles of suspensions of HMP and LMP. The dissolution rates, which were nearly identical for LMP and HMP, were obtained assuming a quasi-infinite reservoir. A reverse-phase HPLC assay with fluorescence detection was used for measuring the concentrations of PE in aqueous humor and corneal samples. Statistical analysis of the bioavailability data showed that suspensions containing HMP and LMP were equal in extent of absorption following a single topical application to the rabbit eye. The results correlated well with the in vitro dissolution rates of the suspensions of HMP and LMP.     

A Theoretical Basis for a Biopharmaceutic Drug Classification: The Correlation of in Vitro Drug Product Dissolution and in Vivo Bioavailability

A biopharmaceutics drug classification scheme for correlating in vitro drug product dissolution and in vivo bioavailability is proposed based on recognizing that drug dissolution and gastrointestinal permeability are the fundamental parameters controlling rate and extent of drug absorption. This analysis uses a transport model and human permeability results for estimating in vivo drug absorption to illustrate the primary importance of solubility and permeability on drug absorption. The fundamental parameters which define oral drug absorption in humans resulting from this analysis are discussed and used as a basis for this classification scheme. These Biopharmaceutic Drug Classes are defined as: Case 1. High solubility-high permeability drugs, Case 2. Low solubility-high permeability drugs, Case 3. High solubility-low permeability drugs, and Case 4. Low solubility-low permeability drugs. Based on this classification scheme, suggestions are made for setting standards for in vitro drug dissolution testing methodology which will correlate with the in vivo process. This methodology must be based on the physiological and physical chemical properties controlling drug absorption. This analysis points out conditions under which no in vitro-in vivo correlation may be expected e.g. rapidly dissolving low permeability drugs. Furthermore, it is suggested for example that for very rapidly dissolving high solubility drugs, e.g. 85% dissolution in less than 15 minutes, a simple one point dissolution test, is all that may be needed to insure bioavailability. For slowly dissolving drugs a dissolution profile is required with multiple time points in systems which would include low pH, physiological pH, and surfactants and the in vitro conditions should mimic the in vivo processes. This classification scheme provides a basis for establishing in vitro-in vivo correlations and for estimating the absorption of drugs based on the fundamental dissolution and permeability properties of physiologic importance.     

Food Effect in Humans: Predicting the Risk Through In Vitro Dissolution and In Vivo Pharmacokinetic Models

In vitro and in vivo experimental models are frequently used to assess a new chemical entity’s (NCE) biopharmaceutical performance risk for food effect (FE) in humans. Their ability to predict human FE hinges on replicating key features of clinical FE studies and building an in vitro-in vivo relationship (IVIVR). In this study, 22 compounds that span a wide range of physicochemical properties, Biopharmaceutics Classification System (BCS) classes, and food sensitivity were evaluated for biorelevant dissolution in fasted- and fed-state intestinal media and the dog fed/fasted-state pharmacokinetic model. Using the area under the curve (AUC) as a performance measure, the ratio of the fed-to-fasted AUC (FE ratio) was used to correlate each experimental model to FE ratio in humans. A linear correlation was observed for the in vitro dissolution-human IVIVR (R² = 0.66, % mean square error 20.7%). Similarly, the dog FE ratio correlated linearly with the FE ratio in humans (R² = 0.74, % mean square error 16.25%) for 15 compounds. Data points near the correlation line indicate dissolution-driven mechanism for food effect, while deviations from the correlation line shed light on unique mechanisms that can come into play such as GI physiology or unusual physicochemical properties. In summary, fed/fasted dissolution studies and dog PK studies show a reasonable correlation to human FE, hence are useful tools to flag high-risk NCEs entering clinical development. Combining kinetic dissolution, dog FE model and in silico modeling one can study FE mechanism and formulation strategies to mitigate the FE risk.KEY WORDS: biorelevant dissolution, dog food effect model, food effect, in vitro-in vivo relationship     

枸橼酸西地那非凝胶剂基质考察及体外溶出度测定

目的:考察枸橼酸西地那非凝胶剂的基质,并对其体外溶出度进行测定.方法:建立枸橼酸西地那非含量测定高效液相色谱法,筛选了该凝胶剂的处方工艺.结果:HPLC法以pH 3.0三乙胺-甲醇-乙腈(58:25:17,V:V:V)作为流动相;采用ZORBAX SB-C18色谱柱(4.6 mm×250 mm,5μm),在5～100μg·mL-1的浓度范围内枸橼酸西地那非线性关系良好,线性方程为Y=25.58X-2.9823,r2=0.9997;通过单因素实验考察,以10％明胶-3％蔗糖作为凝胶基质的处方;通过药物含量及溶出度测定,在1～3 mg·mL-1药物浓度范围内,药物回收与投药量存在线性关系,Y=0.823X+0.053(r2=0.9989),可作为凝胶剂药物含量设定的参考;且在pH 1.0盐酸介质中,3种药物浓度的凝胶剂均有较好的溶出行为.结论:筛选出枸橼酸西地那非凝胶剂优化处方,有利于小儿服用.     

Simultaneous Analysis of Dissolution and Permeation Profiles of Nanosized and Microsized Formulations of Indomethacin Using the In Vitro Dissolution Absorption System 2

The in vitro dissolution absorption system 2 (IDAS2), a recent invention comprised a conventional dissolution vessel containing 2 permeation chambers with Caco-2 cell monolayers mounted with their apical side facing the dissolution media, permits simultaneous measurement of dissolution and permeation of drugs from intact clinical dosage forms. The objectives of this study were (1) to assess the utility of IDAS2 in the determination of the effect of particle size on in vitro performance of indomethacin and (2) to find out whether the behavior in IDAS2 of 2 indomethacin products differing in particle size is correlated with their in vivo behavior. Indomethacin dissolution and permeation across Caco-2 cell monolayers were simultaneously measured in IDAS2; the dissolution and permeation profiles were simultaneously modeled using a simple two-compartment model. Compared to microsized indomethacin, the nanosized formulation increased the dissolution rate constant by fivefold, whereas moderately increasing the permeation rate constant and the kinetic solubility. As a result, the drug amount permeated across the Caco-2 cell monolayers doubled in the nanosized versus microsized formulation. The in vitro results showed a good correlation with in vivo human oral pharmacokinetic parameters, thus emphasizing the physiological relevance of IDAS2 data in predicting in vivo absorption.