Evaluation of Intestinal Drug Absorption and Interaction Using Quadruple Single-Pass Intestinal Perfusion Coupled with Mass Spectrometry Imaging

Visualization and characterization of the intestinal membrane transporter-mediated drug absorption and interaction are challenging due to the complex physical and chemical environment. In this work, an integrated strategy was developed for in situ visualization and assessment of the drug absorption and interaction in rat intestines using quadruple single-pass intestinal perfusion (Q-SPIP) technique coupled with matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI). Compared with the traditional SPIP only available for perfusion of one single intestinal segment, the Q-SPIP model can simultaneously perfuse four individual segments of each rat intestine (duodenum, jejunum, ileum, and colon), enabling to obtain rich data from one rat. Subsequently, the drug distribution and absorption in rat intestinal tissue were accurately visualized by using an optimized MALDI MSI approach. The utility and versatility of this strategy were demonstrated via the examination of P-glycoprotein (P-gp)-mediated intestinal absorption of berberine (BBR) and its combination with natural products possessing inhibitory potency against P-gp. The change in the spatial distribution of BBR was resolved, and MALDI results showed that the signal intensity of BBR in defined regions was enhanced following coperfusion with P-gp inhibitors. However, enhanced absorption of BBR after coperfusion with the P-gp inhibitor was not observed in the ulcerative colitis rat model, which may be due to the damage to the intestinal barrier. This study exemplifies the availability and utility of Q-SPIP coupled with MALDI MSI in the examination of transporter-mediated intestinal drug absorption and interaction for fundamental inquiries into the preclinical prediction of oral absorption and drug interaction potential

Selective Crystallization of Racemic Polymorph <i>via</i> Native Enantiomer Inhibition: dl-Methionine

Crystallization of chiral compounds is dictated by chiral recognition and molecular self-assembly in solution. However, their interplay remains elusive. The reason for the considerably reduced polymorphism in chiral molecules than that of nonchiral molecules remains unclear. Herein, we use a combination of experimental and computational techniques to show that excessive enantiomer functioning, as a native crystallization inhibitor, selectively suppresses the crystallization of racemic polymorphs, affording preferential crystallization of the metastable α polymorph of dl-methionine. Bulk crystallization assays show concomitant crystallization of the α and β polymorphs of racemic dl-methionine in the solution with no enantiomeric excess. However, when the solution contains excessive d-/l-methionine enantiomer, only the metastable α form can be crystallized. Crystal growth experiments, fluoresce confocal microscopy, and atomic force microscope surface topology measurements reveal the growth inhibition of both polymorphs with preferential suppression of the β form by excess native enantiomer. Binding energy calculations and molecular dynamic simulations further demonstrate the preferential adsorption of excessive enantiomers on the (0 0 2) facet of the β form over the α form. Overall, our results uncover a unique chiral self-positioning mechanism where the excess enantiomer solutes serve as a native growth inhibitor to disrupt the kinetics of racemic polymorphic crystallization, affording selective crystallization of only one polymorph of dl-methionine. Our results highlight the important effect of excess enantiomer in a solution on the polymorph occurrence of chiral molecules

Higher-Order Self-Assembly of Benzoic Acid in Solution

Benzoic acid forms hydrogen-bonded dimers in solution that further stack into tetramers by aromatic interactions. Both dimers and higher-order packing motifs are preserved in the resultant crystal structure. The finding hints at the significance in the hierarchy of intermolecular interactions in driving the self-association process in solution

Glycine’s pH-Dependent Polymorphism: A Perspective from Self-Association in Solution

As a simple amino acid, glycine (Gly)’s polymorphism is pH-dependent. The α form is typically obtained from aqueous solution between pH of 4 and 9, while the γ is produced at either lower or higher pH. Formation of cyclic, hydrogen-bonded dimer in water is debated as a possible cause for the formation of the α form. To further understand the pH-dependent polymorphism, our current study examined the self-association of Gly in aqueous solutions under a wide range of pH, utilizing NMR, FTIR, and electronic calculation. The results indicate that glycine molecules form open, not cyclic, hydrogen-bonded dimers in water. It is revealed that the dimerization becomes significant between pH of 4 and 8 but remains trivial at the two pH extremes. The apparent connection between the pH-dependent polymorphism and self-association in solution implies that formation of the α form is driven by the dimerization, and moreover, charged molecular species at the extreme pH facilitate stabilization of γ nuclei

Novel Strategy to Control Polymorph Nucleation of Gamma Pyrazinamide by Preferred Intermolecular Interactions during Heterogeneous Nucleation

Pyrazinamide is usually nucleated from solution as a dimeric form; it has rarely been reported in the γ form (chain structure) crystallized from solution, especially from aqueous solution. Here, we designed a novel way to obtain the γ form of pyrazinamide from aqueous solution. Specific templates were applied to disturb the intrinsic self-association of pyrazinamide molecules and prevent the formation of the dimer structure. In this paper, the heterosynthon design method was applied in pyrazinamide heterogeneous nucleation, in which sulfonamides were chosen as the templates. In the presence of sulfonamide templates, hydrogen bonds between the carbonyl moiety of the amide group in pyrazinamide molecules and the sulfonamide moiety of sulfonamide template molecules were formed; these preferred intermolecular interactions protected the carbonyl groups of PZA, facilitating assembly of PZA molecules in a chain via N–H···N′ and nucleating as the γ form of PZA. This is the first time that the heterosynthon design method was applied to screen effective templates, which can control and select the desired polymorph in heterogeneous nucleation

Persistent Self-Association of Solute Molecules in Solution

The structural evolvement of a solute determines the crystallization outcome. The self-association mechanism leading to nucleation, however, remains poorly understood. Our current study explored the solution chemistry of a model compound, tolfenamic acid (TFA), in three different solvents mainly by solution NMR. It was found that hydrogen-bonded pairs of solute–solute or solute–solvent stack with each through forming a much weaker π–π interaction as the concentration increases. Depending on the solvent, configurations of the solution species may be retained in the resultant crystal structure or undergo rearrangement. Yet, the π–π stacking is always retained in the crystal regardless of the solvent used for the crystallization. The finding suggests that nucleation not only involves the primary intermolecular interaction (hydrogen bonding) but also engages the secondary forces in the self-assembly process

Experimental Determination and Computational Prediction of Androstenedione Solubility in Alcohol + Water Mixtures

This article evaluates the accuracy and applicability of three of the most common solubility models (i.e., Jouyban–Acree, NRTL-SAC, and COSMO-RS) in prediction of androstenedione (AD) solubility in binary mixtures of methanol + water and ethanol + water. The solubilities were measured from (275 to 325) K using medium-throughput experiments and then well represented mathematically by modified Apelblat and CNIBS/Redlich–Kister equations. The computational results show that AD solubility decreases monotonically with increasing water concentration in methanol + water mixtures, but it has a maximum at 0.15–0.30 mole fraction of water in the ethanol aqueous solution. Moreover, the performance of three solubility prediction models in this particular case was compared to identify the advantages and disadvantages of each model. The overall average relative deviation (ARD) for solubility prediction is 4.4% using Jouyban–Acree model, while it is 18.3% with NRTL-SAC model. Surprisingly, COSMO-RS model in combination with reference solubility achieves a good performance for solubility prediction in mixed solvents, including the prediction of synergistic effect of solvents, with overall ARD of only 4.9%

Additional file 1 of Conserved methylation signatures associate with the tumor immune microenvironment and immunotherapy response

Additional file 1: Fig S1. Distribution of DMPs’ median-∆β values between tumor and normal tissues at the pan-cancer level. Fig S2. Top 10 significant Hyper-DMPs across 9 cancer types. Fig S3. Top 10 significant Hypo-DMPs across 9 cancer types. Fig S4. Identification of conserved differentially methylated probes at the pan-cancer level. Fig S5. NMF identifies three hypermethylation signatures and seven hypomethylation signatures. Fig S6. Comparison of Hypo-MSs using β or 1-β values as input. Fig S7. Characterization of DNA methylation signatures. Fig S8. Methylation signature activities’ association with age. Fig S9. Analysis of the correlations between overall survival, cancer stages and methylation signature activities. Fig S10. The relationship between methylation signature activities and tumor immune microenvironment in cancers. Fig S11. The relationship between Tumor mutation burden, neoantigen load, tumor progression and Hypo-MS4 activity. Fig S12. Analysis of the correlations between deterministic genes and Hypo-MS4 activity. Fig S13. Analysis of the intersection of deterministic genes and Hypo-MS4 activity. Fig S14. Analysis of overall survival and ICI response of Hypo-MS4 with deterministic genes status

Solubility of Benzoin in Six Monosolvents and in Some Binary Solvent Mixtures at Various Temperatures

The solubility of benzoin in monosolvents (acetone, ethyl acetate, methanol, ethanol, 1-propanol, and 1-butanol) and binary solvent mixtures (ethyl acetate + methanol, ethyl acetate + ethanol) was measured using UV–vis spectroscopy at temperatures ranging from 283.15 K to 323.15 K. It can be seen from the data that the solubility of benzoin increases expectedly as temperature increases in a given solvent or solvent mixture, the solubility in acetone is maximum among six monosolvents which could be well explained by the existence of strong H-bonds, rather than the “like dissolves like” rule. In binary solvent mixtures, the solubility reaches maximum when the mole fraction of methanol is 0.1 in ethyl acetate + methanol mixed solvents, while the maximum exhibits at 0.2 of mole fraction of ethanol in ethyl acetate + ethanol. The solubility parameter was interpreted as the cosolvency of benzoin solubility in binary solvent mixtures. The solubility data were correlated by modified Apelbalt equation, CNIBS/R-K equation, λ<i>h</i> equation, Jouyban–Acree model, and Van’t–JA equation. Mixing thermodynamic properties were further calculated and discussed regarding their roles in dissolution and solubility

Additional file 1 of Fe-curcumin nanozyme-mediated immunosuppression and anti-inflammation in experimental autoimmune uveitis

Additional file 1: Figure S1. The stability of Fe-curcumin in different condition. (a) Fe-curcumin nanozyme dispersed in water. (b) Fe-curcumin nanozyme dispersed in ethanol. (c) The first day of Fe-curcumin nanozyme dispersed in solution with different pH. (d) The third day of Fe-curcumin nanozyme dispersed in solution with different pH. Figure S2. Like-bioenzyme activity of Nanozymes. (a-b) SOD enzyme activity of Fe-curcumin nanozyme. (c-d) SOD enzyme activity of four common NPs. (e) GPX enzyme activity of four common NPs. Figure S3. Cell differentiation in patients with EAU treated with or without Fe-curcumin nanozyme. Figure S4. Chemical reaction equations for the radical scavenging process. Figure S5. Effective of several NPs in reducing RO