Pinoresinol rescues developmental phenotypes of Arabidopsis phenylpropanoid mutants overexpressing FERULATE 5-HYDROXYLASE.

Most phenylpropanoid pathway flux is directed toward the production of monolignols, but this pathway also generates multiple bioactive metabolites. The monolignols coniferyl and sinapyl alcohol polymerize to form guaiacyl (G) and syringyl (S) units in lignin, components that are characteristic of plant secondary cell walls. Lignin negatively impacts the saccharification potential of lignocellulosic biomass. Although manipulation of its content and composition through genetic engineering has reduced biomass recalcitrance, in some cases, these genetic manipulations lead to impaired growth. The reduced-growth phenotype is often attributed to poor water transport due to xylem collapse in low-lignin mutants, but alternative models suggest that it could be caused by the hyper- or hypoaccumulation of phenylpropanoid intermediates. In Arabidopsis thaliana, overexpression of FERULATE 5-HYDROXYLASE (F5H) shifts the normal G/S lignin ratio to nearly pure S lignin and does not result in substantial changes to plant growth. In contrast, when we overexpressed F5H in the low-lignin mutants cinnamyl dehydrogenase c and d (cadc cadd), cinnamoyl-CoA reductase 1, and reduced epidermal fluorescence 3, plant growth was severely compromised. In addition, cadc cadd plants overexpressing F5H exhibited defects in lateral root development. Exogenous coniferyl alcohol (CA) and its dimeric coupling product, pinoresinol, rescue these phenotypes. These data suggest that mutations in the phenylpropanoid pathway limit the biosynthesis of pinoresinol, and this effect is exacerbated by overexpression of F5H, which further draws down cellular pools of its precursor, CA. Overall, these genetic manipulations appear to restrict the synthesis of pinoresinol or a downstream metabolite that is necessary for plant growth.

The influence of pre-existing hypertension on coronavirus disease 2019 patients.

Hypertension represents one of the most common pre-existing conditions and comorbidities in Coronavirus disease 2019 (COVID-19) patients. To explore whether hypertension serves as a risk factor for disease severity, a multi-centre, retrospective study was conducted in COVID-19 patients. A total of 498 consecutively hospitalised patients with lab-confirmed COVID-19 in China were enrolled in this cohort. Using logistic regression, we assessed the association between hypertension and the likelihood of severe illness with adjustment for confounders. We observed that more than 16% of the enrolled patients exhibited pre-existing hypertension on admission. More severe COVID-19 cases occurred in individuals with hypertension than those without hypertension (21% vs. 10%, P = 0.007). Hypertension associated with the increased risk of severe illness, which was not modified by other demographic factors, such as age, sex, hospital geological location and blood pressure levels on admission. More attention and treatment should be offered to patients with underlying hypertension, who usually are older, have more comorbidities and more susceptible to cardiac complications.

Dissolution of concentrated surfactant solutions: from microscopy imaging to rheological measurements through numerical simulations.

Concentrated aqueous solutions of surfactants, often referred to as pastes, experience complex phase and rheology changes upon dissolution in water, which is a typical step in the production of liquid detergents. During the dilution process, depending on water content, surfactant molecules can arrange in different morphologies, such as lamellar or cubic and hexagonal structures. These phases are characterized by different physico-chemical properties, such as viscosity or diffusivity, which lead to non-simple transport mechanisms during the dissolution process. In this work, we investigate the dissolution of concentrated Sodium Lauryl Ether Sulfate (SLES) pastes in water under quiescent conditions by coupling different experimental techniques. A thorough rheological characterization of the system showed non-monotonic changes of several orders of magnitude in its viscosity and viscoelastic moduli as a function of water content. Time-lapse microscopy allowed us to image the dynamic evolution of the phase changes as water penetrated in a disk-shaped sample (with the same geometry used in rheological tests). Numerical simulation, based on a simple diffusion-based multi-parameter model is shown to describe satisfactorily SLES dissolution data.

Comparison of biorelevant simulated media mimicking the intestinal environment to assess the solubility profiles of poorly soluble drugs.

During the discovery stage in lead identification/optimization, compounds are characterized for their solubilities in biorelevant media and these data are often used to model the in vivo behavior of the compounds and predict the fraction absorbed. These media are selected to closely approximate the composition of human intestinal fluid. Owing to the complexity and variability in human intestinal fluid composition, it is essential that the chosen simulated media mimic the in vivo condition as closely as possible. Several recipes have been developed and are routinely used in assessing the solubilities of compounds. It is necessary to revisit these recipes and modify them as the understanding of the human GI tract increases. In the present work, we have evaluated the solubilities of six model compounds in several media and have proposed slight modifications to the currently used recipes based on our own data and that reported in the literature.

Correlation of inhibitory effects of polymers on indomethacin precipitation in solution and amorphous solid crystallization based on molecular interaction.

PURPOSE: To correlate the polymer's degree of precipitation inhibition of indomethacin in solution to the amorphous stabilization in solid state. METHODS: Precipitation of indomethacin (IMC) in presence of polymers was continuously monitored by a UV spectrophotometer. Precipitates were characterized by PXRD, IR and SEM. Solid dispersions with different polymer to drug ratios were prepared using solvent evaporation. Crystallization of the solid dispersion was monitored using PXRD. Modulated differential scanning calorimetry (MDSC), IR, Raman and solid state NMR were used to explore the possible interactions between IMC and polymers. RESULTS: PVP K90, HPMC and Eudragit E100 showed precipitation inhibitory effects in solution whereas Eudragit L100, Eudragit S100 and PEG 8000 showed no effect on IMC precipitation. The rank order of precipitation inhibitory effect on IMC was found to be PVP K90 > Eudragit E100 > HPMC. In the solid state, polymers showing precipitation inhibitory effect also exhibited amorphous stabilization of IMC with the same rank order of effectiveness. IR, Raman and solid state NMR studies showed that rank order of crystallization inhibition correlates with strength of molecular interaction between IMC and polymers. CONCLUSIONS: Correlation is observed in the polymers ability to inhibit precipitation in solution and amorphous stabilization in the solid state for IMC and can be explained by the strength of drug polymer interactions.

[Reliability of estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 expression in breast cancer evaluated by immunohistochemistry].

OBJECTIVE: To evaluate the reliability of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER-2) expression in breast cancer by immunohistochemistry and discuss their influencing factors. METHODS: The pretreatment biopsy specimens were collected from 148 patients (from Beijing Cancer Hospital between 2004 to 2010) with invasive breast cancer. After reslicing and staining (ER:SP1, PR: 1E2, HER-2: 4B5), the status of ER, PR and HER-2 was analyzed by a pathological expert with automated imaging system Ariol MB-8. And their results were compared with the original reports. RESULTS: The concordance rates between original reports and automated image system were ER:76.35%, PR:49.32%, HER-2:63.51% while Kappa values 0.12 (P = 0.020) , 0.18 (P = 0.002) and 0.08 (P = 0.200) respectively. And the concordance rates between expert reports and automated image system were ER:93.92%, PR:81.08% and HER-2:76.35% while Kappa values 0.77 (P < 0.001) , 0.67 (P < 0.001) and 0.32 (P < 0.001) respectively. CONCLUSION: For the expressions of ER, PR and HER-2, the disaccording results of original reports and automated image system may be mainly due to the differences of antibodies, staining methods and interpretations.

Predictors of contrast-induced acute kidney injury in patients with coronary artery disease receiving contrast agents twice within 30 days.

BACKGROUND: None of study mentioned about contrast-induced acute kidney injury (CI-AKI) in people who have received contrast agents twice within in a short period of time. This study is trying to identify the predictors. METHODS: We enrolled 607 patients between Oct. 2010 and Jul. 2015 who received contrast agents twice within 30 days in the Department of Cardiology of the General Hospital of Shenyang Military Region. The primary outcome was CI-AKI within 72 h after contrast agent exposure. Patients were divided into groups A (n = 559) and group B (n = 48) according to whether CI-AKI occurred after the second agent. RESULTS: Patients in group B (CI-AKI occurred after the second agent) had a more rapid heart rate and more usage of diuretics and digitalis. In group B, CI-AKI occurred more frequently after the first agent. Multivariate logistic regression showed that diuretic (P = 0.006) and intra-aortic balloon pump (IABP) usage (P = 0.012) were independent predictors of CI-AKI after the first agent. Angiotensin-converting enzyme inhibitor/Angiotensin II receptor antagonist (ACEI/ARB) usage (P = 0.039), IABP usage (P = 0.040) and CI-AKI occurring after administration of the first agent (P = 0.015) were independent predictors of CI-AKI after the second. Furthermore, dividing the patients into tertiles of the time interval between the two agents showed that CI-AKI occurred more frequently when the second agent was administered within 1-3 days after the first exposure than within 4-6 days (12.4% vs. 5.0%, P = 0.008) or ≥ 7 days (12.4% vs. 6.4%, P = 0.039). CONCLUSIONS: Diuretic and IABP usage are independent predictors of CI-AKI following exposure to a first contrast agent. The major predictors of CI-AKI after exposure to a second agent are time since the first contrast exposure, ACEI/ARB usage, and IABP usage. More importantly, a three-day interval between the two agents is associated with a higher incidence of CI-AKI following the second administration.

Pre-existing Health Conditions and Epicardial Adipose Tissue Volume: Potential Risk Factors for Myocardial Injury in COVID-19 Patients.

Background: Myocardial injury is a life-threatening complication of coronavirus disease 2019 (COVID-19). Pre-existing health conditions and early morphological alterations may precipitate cardiac injury and dysfunction after contracting the virus. The current study aimed at assessing potential risk factors for COVID-19 cardiac complications in patients with pre-existing conditions and imaging predictors. Methods and Results: The multi-center, retrospective cohort study consecutively enrolled 400 patients with lab-confirmed COVID-19 in six Chinese hospitals remote to the Wuhan epicenter. Patients were diagnosed with or without the complication of myocardial injury by history and cardiac biomarker Troponin I/T (TnI/T) elevation above the 99th percentile upper reference limit. The majority of COVID-19 patients with myocardial injury exhibited pre-existing health conditions, such as hypertension, diabetes, hypercholesterolemia, and coronary disease. They had increased levels of the inflammatory cytokine interleukin-6 and more in-hospital adverse events (admission to an intensive care unit, invasive mechanical ventilation, or death). Chest CT scan on admission demonstrated that COVID-19 patients with myocardial injury had higher epicardial adipose tissue volume ([EATV] 139.1 (83.8-195.9) vs. 92.6 (76.2-134.4) cm2; P = 0.036). The optimal EATV cut-off value (137.1 cm2) served as a useful factor for assessing myocardial injury, which yielded sensitivity and specificity of 55.0% (95%CI, 32.0-76.2%) and 77.4% (95%CI, 71.6-82.3%) in adverse cardiac events, respectively. Multivariate logistic regression analysis showed that EATV over 137.1 cm2 was a strong independent predictor for myocardial injury in patients with COVID-19 [OR 3.058, (95%CI, 1.032-9.063); P = 0.044]. Conclusions: Augmented EATV on admission chest CT scan, together with the pre-existing health conditions (hypertension, diabetes, and hyperlipidemia) and inflammatory cytokine production, is associated with increased myocardial injury and mortality in COVID-19 patients. Assessment of pre-existing conditions and chest CT scan EATV on admission may provide a threshold point potentially useful for predicting cardiovascular complications of COVID-19.

Genome-wide analysis of single nucleotide polymorphisms in Bordetella pertussis using comparative genomic sequencing.

Bordetella pertussis is known to be a genotypically homogeneous pathogen but the extent of homogeneity at the genomic level is unknown. A currently circulating B. pertussis isolate from Australia was compared with the genome-sequenced Tohama I strain isolated in Japan in the 1950s from a distantly related lineage. Microarray-based comparative genome sequencing (CGS) was used to detect single nucleotide polymorphisms (SNPs) in a total of 1.4 Mb of the 4.09 Mb genome, including 1012 coding-regions, 217 pseudogenes and 268 intergenic regions. The CGS analysis, followed by validation using real-time PCR and DNA sequencing, identified 70 SNPs and five 1-3 bp indels, giving an overall frequency of base changes of 1 per 20 kb. Thirty-two of the 56 SNPs in coding regions were non-synonymous, including five located in virulence-associated genes. The data also allowed us to compare genomic diversity with other "clonal" human pathogens such as Mycobacterium tuberculosis and Yersinia pestis, showing that B. pertussis may be one of the least variable pathogenic bacterial species.

Design of surface active soluble peptide molecules at the air/water interface.

Surface active molecules collect at interfaces and have the potential to be used for water evaporation reduction. The objective of this work is to design surface active soluble peptides that collect at the air/water interface using molecular simulations. Rotational isomeric state Monte Carlo (RISMC) sampling together with a solvation model that we recently invented, the AAD solvation model [Gu, C.; Lustig, S.; Trout, B. J. Phys. Chem. B 2006, 110 (3), 1476-1484] was applied to calculate the adsorption free energy of the peptide molecule at the air/water interface. The results were validated by both molecular dynamics simulations with an explicit solvent model and surface tension measurements on synthesized peptides. It was demonstrated that this approach is able to give a reasonable prediction of surface activity with an approximately 50% hit rate in terms of designed surface active molecules actually being surface active. The relationship between the chemical composition and the surface morphology is also discussed.

Risk Analysis of Earth-Rock Dam Failures Based on Fuzzy Event Tree Method.

Earth-rock dams make up a large proportion of the dams in China, and their failures can induce great risks. In this paper, the risks associated with earth-rock dam failure are analyzed from two aspects: the probability of a dam failure and the resulting life loss. An event tree analysis method based on fuzzy set theory is proposed to calculate the dam failure probability. The life loss associated with dam failure is summarized and refined to be suitable for Chinese dams from previous studies. The proposed method and model are applied to one reservoir dam in Jiangxi province. Both engineering and non-engineering measures are proposed to reduce the risk. The risk analysis of the dam failure has essential significance for reducing dam failure probability and improving dam risk management level.

Solvation model based on order parameters and a fast sampling method for the calculation of the solvation free energies of peptides.

An analytical solvation model is proposed as a function of an order parameter, which represents the local arrangement of water molecules in the first solvation shell of peptide atoms. The model is combined with a fast sampling method, rotational isomeric state Monte Carlo, to sample efficiently the torsional degrees of freedom on a peptide backbone. This order parameter solvation model is shown to reproduce without ad hoc fitting parameters the solvation free energies of single amino acids and tripeptides with slightly better accuracy than the generalized Born model but with several orders of magnitude improvement in efficiency. This method is a potential candidate for efficiently and accurately tackling some important issues in biophysical chemistry that are related to solvation, for example, protein folding, ligand binding, etc. Our results also present fundamental new insights into solvation. Specifically, the local water geometry, represented in this work by a properly defined order parameter, carries the majority, if not all, of the energetic information of solvation, including solute-solvent interactions and solvent reorganization in the presence of the solute.

Efficacy and safety of fondaparinux versus enoxaparin in patients undergoing percutaneous coronary intervention treated with the glycoprotein IIb/IIIa inhibitor tirofiban.

BACKGROUND: In worldwide, the mortality rate of acute myocardial infarction (AMI) raises year by year. Although the applications of percutaneous coronary intervention (PCI) and anticoagulants effectively reduce the mortality of patients with acute coronary syndrome (ACS), but also increase the incidence of bleeding. Therefore, drugs with stable anticoagulant effects are urgently required. METHODS: We enrolled 894 patients with acute coronary syndrome who underwent percutaneous coronary intervention in Shenyang Northern Hospital from February 2010 to May 2012; 430 patients were included in the fondaparinux group (2.5 mg/d), and 464 were included in the enoxaparin group (1 mg/kg twice daily). Fondaparinux and enoxaparin were applied for 3-7 days. All patients were treated with tirofiban (10 µg/kg for 3 min initially and 0.15 µg/(kg · min) for 1 to 3 days thereafter). The primary efficacy endpoint was the incidence of a major adverse cerebrovascular or cardiovascular event. The primary safety endpoint was bleeding within 30 days and 1 year after percutaneous coronary intervention. RESULTS: One-year data were available for 422 patients in the fondaparinux group and for 453 in the enoxaparin group. The incidence of a major adverse cerebrovascular or cardiovascular event (10.9 % vs 12.6 %, P = 0.433) and cardiac mortality (0.5 % vs 1.5 %, P = 0.116) were generally lower in the fondaparinux group than in the enoxaparin group, although the differences were not significant. Compared with the enoxaparin group, the fondaparinux group had a significantly decreased rate of bleeding at 30 days (0.9 % vs 2.8 %) and 1 year (2.4 % vs 5.4 %). In addition, the rate of major bleeding events was lower in the fondaparinux group, but this difference was not significant (0.2 % vs 0.9 %, 0.2 % vs 1.1 %). CONCLUSIONS: In tirofiban-treated patients with acute coronary syndrome undergoing percutaneous coronary intervention, fondaparinux presented similar efficacy for ischemia events as enoxaparin. However, fondaparinux significantly decreased the incidence of bleeding, thus providing safer anticoagulation therapy.

Using a novel multicompartment dissolution system to predict the effect of gastric pH on the oral absorption of weak bases with poor intrinsic solubility.

A novel multicompartment dissolution system was developed by modifying a conventional six-vessel United States Pharmacopoeia dissolution system to study the dissolution and possible precipitation of poorly soluble weak bases after oral administration. The modified system includes a "gastric" compartment, an "intestinal" compartment, an "absorption" compartment, and a reservoir to simulate the dissolution and absorption in the gastrointestinal tract. Dissolution profiles of 50-mg dipyridamole (pK(a) 6.0, 12.5) tablet (2 * 25 mg Persantine tablets), 25- and 50-mg cinnarizine (pK(a) 1.95, 7.5) powders, which are poorly soluble weak bases, were generated in the system using dissolution medium with different pHs in the "gastric" compartment. The in vitro dissolution results were compared with the in vivo oral exposure data in humans. For both dipyridamole and cinnarizine, the in vitro dissolution using the multicompartment system was able to predict the pH effect on oral exposure. The results from the multicompartment system are more closely correlated with the in vivo data, compared with that from the conventional dissolution test. The system showed that although both dipyridamole and cinnarizine completely dissolved in the gastric compartment at lower pH, approximately 36% (at 25-mg dose) and 40% (at 50-mg dose) of cinnarizine precipitated in the "intestinal" compartment whereas the precipitation of dipyridamole was <10% of the initial dose. The difference in the amount "absorbed" between these two compounds in vitro is therefore primarily attributed to the precipitation potential, although no in vivo data are available to confirm this result. The difference in the amount precipitated may be explained by the lower solubility and consequently higher degree of supersaturation of cinnarizine in the "intestinal" compartment.

A Mechanistic Assessment of the Discordance between Normal Serum Alanine Aminotransferase Levels and Altered Liver Histology in Chronic Hepatitis B.

To understand the mechanisms underlying the discordance between normal serum alanine aminotransferase (ALT) levels and significant alterations in liver histology of chronic hepatitis B virus (HBV) infection with persistent normal ALT (PNALT) or minimally elevated ALT. A total of 300 treatment-naive chronic HBV-infected patients with PNALT (ALT ≤ upper limit of normal [ULN, 40 U/ml]) or minimally elevated ALT (1-2×ULN) were retrospectively enrolled. All patients underwent liver biopsy and histological changes were analyzed along with biochemical and HBV markers. Among 300 participants, 177 were HBeAg-positive and 123 HBeAg-negative. Significant histologic abnormalities were found in 42.9% (76/177) and 52.8% (65/123) of HBeAg-positive and HBeAg-negative patients, respectively. Significant fibrosis, which is a marker of prior injury, was more frequently detected than significant necroinflammation (suggesting active liver injury) in both HBeAg-positive and -negative groups, suggesting that liver injury occurred intermittently in our cohort. No significant differences were noticed in the percentage of patients with severe fibrosis between HBeAg-positive and negative phases or between ages 30 and 40 and over 40, suggesting that the fibrosis was possibly carried over from an early phase. Finally, lowering ALT ULN (30 U/L for men, 19 U/L for women) alone was not adequate to increase the sensitivity of ALT detection of liver injury. However, the study was limited to a small sample size of 13 HBeAg-positive patients with ALT in the revised normal range. We detected significant liver pathology in almost 50% of chronic HBV infected patients with PNALT (ALT ≤ 40 U/ml) or minimally elevated ALT. We postulated that small-scale intermittent liver injury was possibly responsible for the discordance between normal serum ALT and significant liver changes in our cohort.

Grouping solvents by statistical analysis of solvent property parameters: implication to polymorph screening.

The success rate of discovering new polymorphs by crystallization from solution may be increased if solvents with diverse properties are used during initial polymorph screening. In this study, eight solvent parameters, including hydrogen bond acceptor propensity, hydrogen bond donor propensity, polarity/dipolarity, dipole moment, dielectric constant, viscosity, surface tension and cohesive energy density (equal to square of solubility parameter), of 96 solvents were collected. Using the cluster statistical analysis of the parameters, these 96 solvents were separated into 15 solvent groups. Such solvent groups may provide guidelines for the judicious choice of solvents with diverse properties for polymorph screening.

Importance of using physiologically relevant volume of dissolution medium to correlate the oral exposure of formulations of BMS-480188 mesylate.

BMS-480188 is a weak base. The aqueous solubility of BMS-480188 is 0.036 mg/ml at pH 6.5 at 37 degrees C. The mesylate salt of BMS-480188 was prepared to improve its solubility. Capsules containing mesylate salt alone (Formulation A) or mesylate salt with excipients, including lactose, croscarmellose sodium, sodium lauryl sulfate, syloid and magnesium stearate (Formulation B), were prepared. Both formulations show similar dissolution profiles in 1l 0.01N HCl at 37 degrees C. However, the bioavailability of Formulations A and B is 5.7 and 24%, respectively, in monkeys. Since very small amount of fluid is available in the stomach of monkeys in fasted state, 30 ml of 0.01N HCl was used as the dissolution medium to simulate the ratio of the drug to dissolution medium in vivo. The dissolution studies in 30 ml of 0.01N HCl show that the amount of drug dissolved from the Formulation B is 80% greater than the Formulation A after 2h. These results are consistent with the higher bioavailability of the formulated capsules. The pK(a) of the free base is 3.0 and the apparent solubility of the mesylate salt (>20mg/ml) is much greater than the equilibrium solubility of BMS-480188 (1.08 mg/ml) in 0.01N HCl at 37 degrees C. Therefore, the mesylate salt of BMS-480188 converts to the free base in 0.01N HCl. The presence of excipients delays the conversion of the mesylate salt to the free base in the dissolution test using 30 ml medium, leading to a greater percentage of the dissolved drugs. This inhibitory effect of excipients is masked during the dissolution using 1l medium because the concentration of the dissolved drug is below the solubility limit of BMS-480188. This study demonstrates the importance of the volume of the dissolution medium for the in vitro dissolution test to qualitatively predict the bioavailability of a salt of weak base with low intrinsic aqueous solubility.

Correlating the behavior of polymers in solution as precipitation inhibitor to its amorphous stabilization ability in solid dispersions.

Our major goals were to understand the mechanism of dipyridamole (DPD) precipitation inhibition in the presence of polymers and to correlate the polymers-mediated precipitation inhibition in solution to the amorphous stabilization in the solid state. A continuous UV spectrophotometer was used to monitor the DPD concentration with time in the absence and presence of different polymers. Six polymers: PVP K90, hydroxypropylmethylcellulose (HPMC), Eudragit E100, Eudragit S100, Eudragit L100, and PEG 8000 were screened at different drug-to-monomer ratios. Solid dispersions were characterized by X-ray powder diffraction and modulated differential scanning calorimetry, whereas infrared (IR) and Raman were used to investigate the possible drug-polymer interactions. Eudragit E100 and HPMC were found to delay both DPD precipitation initiation time and precipitation rates. Eudragit S100 delayed only the precipitation initiation time and PVP K90 decreased only the precipitation rates. In solid state, Eudragit S100, PVP K90, HPMC, and Eudragit L100 were effective stabilizers of the DPD solid dispersion. Eudragit S100 was found to be most effective DPD-stabilizing polymer. The IR and Raman spectra of the solid dispersion of Eudragit S100 and HPMC showed peak shift, indicating drug-polymer molecular interactions. It is concluded that the drug-polymer interaction plays a significant role in precipitation inhibition and amorphous stabilization.

Predicting effect of food on extent of drug absorption based on physicochemical properties.

PURPOSE: To develop a statistical model for predicting effect of food on the extent of absorption (area under the curve of time-plasma concentration profile, AUC) of drugs based on physicochemical properties. MATERIALS AND METHODS: Logistic regression was applied to establish the relationship between the effect of food (positive, negative or no effect) on AUC of 92 entries and physicochemical parameters, including clinical doses used in the food effect study, solubility (pH 7), dose number (dose/solubility at pH 7), calculated Log D (pH 7), polar surface area, total surface area, percent polar surface area, number of hydrogen bond donor, number of hydrogen bond acceptors, and maximum absorbable dose (MAD). RESULTS: For compounds with MAD >or= clinical dose, the food effect can be predicted from the dose number category and Log D category, while for compounds with MAD < clinical dose, the food effect can be predicted from the dose number category alone. With cross validation, 74 out of 92 entries (80%) were predicted into the correct category. The correct predictions were 97, 79 and 68% for compounds with positive, negative and no food effect, respectively. CONCLUSIONS: A logistic regression model based on dose, solubility, and permeability of compounds is developed to predict the food effect on AUC. Statistically, solubilization effect of food primarily accounted for the positive food effect on absorption while interference of food with absorption caused negative effect on absorption of compounds that are highly hydrophilic and probably with narrow window of absorption.