Oil-water Partition Coefficient Research Articles

Dynamic Partitioning of Surfactants into Nonequilibrium Emulsion Droplets.

Characterizing the propensity of molecules to distribute between fluid phases is key to describing chemical concentrations in heterogeneous mixtures and the corresponding physiochemical properties of a system. Typically, partitioning is studied under equilibrium conditions. However, some mixtures form a single phase at equilibrium but exist in multiple phases when out-of-equilibrium, such as oil-in-water emulsion droplets stabilized by surfactants. Such droplets persist for extended times but ultimately disappear due to droplet dissolution and micellar solubilization. Consequently, equilibrium properties like oil-water partition coefficients may not accurately describe out-of-equilibrium droplets. This study investigates the partitioning of nonionic surfactants between shrinking microscale oil droplets and water under nonequilibrium conditions. Quantitative mass spectrometry is used to analyze the composition of individual microdroplets over time under conditions of varying surfactant composition, concentrations, and oil molecular structures. Within minutes, nonionic surfactants partition into oil droplets, reaching a nonequilibrium steady-state concentration that can be over an order of magnitude higher than that in the aqueous phase. As the droplets solubilize over hours, the surfactants are released back into water, leading to transiently high surfactant concentrations near the droplet-water interface and the formation of a microemulsion phase with a low interfacial tension. Introducing ionic surfactants that form mixed micelles with nonionic surfactants reduces partitioning. Based on this observation, stimuli-responsive ionic surfactants are used to modulate the nonionic surfactant partitioning and trigger reversible phase separation and mixing inside binary oil droplets. This study reveals generalizable nonequilibrium states and conditions experienced by solubilizing oil droplets that influence emulsion properties.

Construction of a physiologically based pharmacokinetic model of paclobutrazol and exposure estimation in the human body

Paclobutrazol (PBZ) is a plant growth regulator that can delay plant growth and improve plant resistance and yield. Although it has been widely used in the growth of medicinal plants, human beings may take it by taking traditional Chinese medicine. There are no published studies on PBZ exposure in humans or standardized limits for PBZ in medicinal plants. We measured the solubility, oil–water partition coefficient (logP), and pharmacokinetics of PBZ in rats and established a physiologically based pharmacokinetic (PBPK) model of PBZ in rats. This was followed by extrapolation to healthy Chinese adult males as a theoretical foundation for future risk assessment of PBZ. The results showed that PBZ had low solubility and high fat solubility. Pharmacokinetic experiments showed that PBZ was absorbed rapidly but eliminated slowly in rats. On this basis, the rat PBPK model was successfully constructed and extrapolated to healthy Chinese adult males to predict the plasma concentration–time curve and exposure of PBZ in humans. The construction of the PBPK model of PBZ in this study facilitates the determination of the standard formulation limits and risk assessment of PBZ residues in medicinal plants.

Energetics and Kinetics of Membrane Permeation of Photoresists for Bioprinting

Abstract3D bioprinting is a promising technology which typically uses bioinks to pattern cells and their scaffolds. The selection of cytocompatible inks is critical for the printing success. In laser‐based 3D bioprinting, photoresist molecules are used as bioinks. However, the interaction of photoresists with lipid membranes and their permeation into the cell remains poorly understood. Here, molecular dynamics simulations and in vitro assays address this issue, retrieving partition coefficients, free energies, and permeabilities for twelve commonly used photoresists in model lipid bilayers. Crossing the hydrophobic center of the membrane constitutes the rate limiting step during permeation. In addition, three photoresists feature a preferential localization site at the acyl chain head group interface. Photoresist permeabilities range over ten orders of magnitude, with some molecules being membrane‐permeable on bioprinting timescales. Moreover, permeation correlates well with the oil–water partition coefficients and is severely hampered by the lipid ordering imposed by the lipid saturation. Overall, the mechanism of interaction of photoresists with model lipid bilayers is provided here, helping to classify them according to their residence in the membrane and permeation through it. This is useful information which will help guide the selection of cytocompatible photoresists for 3D bioprinting.

A Combination of Magnoflorine and Spinosin Improves the Antidepressant effects on CUMS Mouse Model.

Depression is a common neuropsychiatric disease. As a famous traditional Chinese medicine with significant anti-depressive and sleep-promoting effects, Ziziphi Spinosae Semen (ZSS) has attracted the attention of many researchers. Although it is well known that Magnoflorine (MAG) and Spinosin (SPI) were the main active components isolated from ZSS, there is a lack of research on the combined treatment of depression with these two ingredients. The shaking bottle method was used to simulate the human environment for detecting the changes in oil-water partition coefficient before and after the drug combination. Cell viability was evaluated by the MTT assay. To establish a mouse model of depression and insomnia by CUMS method, and then to explore the effect of combined administration of MAG and SPI on depression in CUMS model by observing behavior and analyzing pharmacokinetics. The change in LogP values affected the lipid solubility of MAG and increased the water solubility of SPI, allowing them to penetrate more easily through the blood-brain barrier into the brain. Compared with the model group, MAG-SPI with a concentration of 60 μM significantly increased cell survival rate. In both the TST and FST experiments, the mice showed a decrease in immobilization time. Pharmacokinetic results showed that the pharmacokinetic parameters, Cmax and AUC of MAG and SPI, were increased in the case of combination, which resulted in enhancement of their relative bioavailability and improvement of in vivo effects. The present study demonstrated that a combination of MAG and SPI had a synergistic antidepressant effect in CUMS mouse model.

A comprehensive study on flavor/cyclodextrin inclusion complexes

Flavors, being highly volatile compounds used in various circumstance, often require encapsulation to facilitate their handling and processing. Among different encapsulation strategies, molecular inclusion complexation with cyclodextrins through host-guest interactions is one of the most commonly employed approach. This study focuses on the fabrication of different kinds of flavor/cyclodextrin inclusion complexes and the identification of inclusion regularities, as well as the prediction of encapsulation results based on the chemical structures and oil-water partition coefficients of flavors. Meanwhile, the property characterizations of representative inclusion complexes confirm improvements in sustained release ability and flavors stability. These inclusion complexes have potential applications in the fields of food and tobacco processing. Furthermore, we successfully prepare the inclusion products with stable loading capacities and yields in a 100 L reactor, suggesting the significant potential for industrial-scaled production using the preparation method for flavor/cyclodextrin inclusion complexes outlined in this study.

How Digestive Processes Can Affect the Bioavailability of PCBs Associated with Microplastics: A Modeling Study Supported by Empirical Data.

The transfer kinetics of plastic-associated chemicals during intestinal digestive processes is unknown. Here, we assessed whether digestive processes affect chemical exchange kinetics on microplastics, using an in vitro gut fluid digestive model mimicking the human upper intestinal tract. Chemical exchange kinetics of microplastics were measured for 10 polychlorinated biphenyls (PCBs) as proxies for the broad class of hydrophobic organic chemicals. Following earlier studies, olive oil was used as a proxy for digestible food, under high and low digestive enzyme activities. The micelle-water and oil-water partition coefficients of the 10 PCBs were also determined to evaluate the relative contribution of each gut component to sorb PCBs. A new biphasic and reversible chemical exchange model, which included the digestion process, fitted well to the empirical data. We demonstrate that the digestive processes that break down contaminated food can lead to a substantial increase in chemical concentration in microplastics by a factor of 10-20, thereby reducing the overall chemical bioavailability in the gastrointestinal tract when compared to a scenario without microplastics. Higher enzyme activities result in more chemicals being released by the digested food, thereby resulting in higher chemical concentrations in the microplastics. While the model-calibrated kinetic parameters are specific to the studied scenario, we argue that the mechanism of the reduced bioavailability of chemicals and the modeling tool developed have generic relevance. These digestive processes should be considered when assessing the risks of microplastics to humans and also biomagnification in aquatic food webs.

Design and structure optimization of novel butenolide derivatives as low bee-toxicity candidates

The discovery of new neonicotinoid alternatives with high efficiency against pests and eco-safety toward bees has become an increasingly urgent need in recent years. The relationship between the oil-water partition coefficient (logP) and the bee-toxicity of commercial nicotinic acetylcholine receptor (nAChR) competitive modulators was explored in this work. Compared compounds with a high bee-toxicity, compounds with low bee-toxicity were found to have higher logP values. Therefore, two series of novel butenolide derivatives with different hydrophobic groups were designed and synthesized by including different hydrophobic groups. The insecticidal activity study showed that compounds I-01 (LC50=112.96 μg/mL), II-05 (LC50=124.68 μg/mL), and II-11 (LC50=87.89 μg/mL) were with higher insecticidal activity against Aphis glycines and lower calculated logP values among all synthesized compounds. Molecular dynamics simulations indicated that three butenolide compounds formed some hydrogen bonding or π-π stacking interactions with insect acetylcholine binding protein (AChBP). In addition, the bee-toxicity bioassay also showed that compounds I-01, II-05 and II-11 were with much lower contact bee-toxicity than imidacloprid. The possible mechanism of the bee toxicity of the novel butenolide compounds was explored based on the nAChR function subunit AmeIα8/ratβ2. This study will provide rational guidance on novel butenolide compounds as low-bee-toxicity candidates based on their molecular hydrophobic properties.

Partitioning of caffeine and quinine in oil-in-water emulsions and effects on bitterness.

The bulk vegetable oil-water partition coefficient of caffeine and quinine was determined by a shake-flask method as log Kow =-1.32 and 2.97. These values were consistent with the effect of oil concentration on the distribution of the bitterants in an oil-in-water emulsion (0-2 and 0-20wt% oil stabilized with 0.125 and 1wt% whey protein isolate, respectively). For example, in a 20% o/w emulsion, approximately 90% of the total caffeine remained in the aqueous phase, whereas in a 2% o/w emulsion, only ∼20% of the quinine remained in the aqueous phase. The intensity of the bitter taste of caffeine and quinine in emulsions was assessed by a large cohort (n=100) of untrained participants. An increase in fat in the emulsions (from 0.5wt% to 2wt% oil emulsions stabilized with 0.125wt% whey protein isolate) caused a significant decrease inperceivedbitternessthat was accompanied by adecrease in the aqueous concentration of the hydrophobic bitterant quinine Specifically, the bitterness of quinine was reduced ∼13% in the o/w emulsion with more fat, and this drop paralleled a drop in the aqueous concentration and was generally consistent with aqueous dose-response functions published elsewhere. For the hydrophilic bitterant caffeine, there was nosignificant change in theperceivedbitterness or aqueous concentration with changing oil concentration. We conclude that the perceived bitterness of a hydrophobic bitterant like quinine in an emulsion depends on the aqueous concentration rather than the overall concentration.

Characterization of the inhibition of aldose reductase with p-coumaric acid ethyl ester.

The inhibition of aldose reductase is an effective strategy to alleviate symptoms of diabetic complications. The p-coumaric acid ethyl ester (p-CAEE) was taken as an example to investigate the inhibition of aldose reductase from p-coumaric acid derivations. The results showed p-CAEE strongly inhibited aldose reductase with the half inhibitory concentration of 1.92 μM, following the noncompetitive manner with a Ki value of 0.94 μM. After binding with p-CAEE, the enzyme showed increased β-sheet content, and the α-helix content, random coil content, and intrinsic fluorescence strength decreased. p-CAEE bonded with aldose reductase at the anionic, hydrophobic, and selective pockets of the enzyme, via hydrogen bond and hydrophobic interactions with Thr113, Cys80, Trp111, and Leu300, etc. The strong inhibition was related to the high oil-water partition coefficient and special esterify group. This study provides new information to develop aldose reductase inhibitors from p-coumaric acid derivations. PRACTICAL APPLICATIONS: Inhibition of aldose reductase is an effective strategy to alleviate and control the symptoms of diabetic complications. In this study, it has been shown that p-coumaric acid ethyl ester could strongly inhibit the aldose reductase. In addition, the inhibition of aldose reductase was been correlated with structures and oil-water partition coefficients of p-coumaric acid derivatives. It provides a theoretical basis for the development of effective aldose reductase inhibitors.

An Exploration of the Effect of the Kleier Model and Carrier-Mediated Theory to Design Phloem-Mobile Pesticides Based on Researching the N-Alkylated Derivatives of Phenazine-1-Carboxylic Acid-Glycine.

The Kleier model and Carrier-mediated theory are effective for molecularly designing pesticides with phloem mobility. However, the single Kleier model or Carrier-mediated theory cannot achieve a reliable explanation of the phloem mobility of all exogenous substances. A detailed investigation of the two models and the scope of their applications can provide a more accurate and highly efficient basis for the guidance of the design and development of phloem-mobile pesticides. In the present paper, a strategy using active ingredient-amino acid conjugates as mode compounds is developed based on Carrier-mediated theory. An N-alkylated amino acid is used to improve the pesticide’s physicochemical properties following the Kleier model, thus allowing the conjugates to fall on the predicted and more accessible transportation region of phloem. Moreover, the influence of this movement on phloem is inspected by the Kleier model and Carrier-mediated theory. To verify this strategy, a series of N-alkylated phenazine-1-carboxylic acid-glycine compounds (PCA-Gly) were designed and synthesized. The results related to the castor bean seeds (R. communis L.) indicated that all the target compounds (4a–4f) had phloem mobility. The capacity for phloem mobility shows that N-alkylated glycine containing small substituents can significantly improve PCA phloem mobility, such as 4c(i-C3H7-N) > 4a(CH3-N) ≈ 4b(C2H5-N) > 4d (t-C4H9-N) > PCA-Gly > 4e(C6H5-N) > 4f(CH2COOH-N), with an oil–water partition coefficient between 1.2~2.5. In particular, compounds 4a(CH3-N), 4b(C2H5-N), and 4c(i-C3H7-N) present better phloem mobility, with the average concentrations in phloem sap of 14.62 μΜ, 13.98 μΜ, and 17.63 μΜ in the first 5 h, which are 8 to 10 times higher than PCA-Gly (1.71 μΜ). The results reveal that the Kleier model and Carrier-mediated theory play a guiding role in the design of phloem-mobile pesticides. However, the single Kleier model or Carrier-mediated theory are not entirely accurate. Still, there is a synergism between Carrier-mediated theory and the Kleier model for promoting the phloem transport of exogenous compounds. Therefore, we suggest the introduction of endogenous plant compounds as a promoiety to improve the phloem mobility of pesticides through Carrier-mediated theory. It is necessary to consider the improvement of physicochemical properties according to the Kleier model, which can contribute to a scientific theory for developing phloem-mobile pesticides.

Design, synthesis and anti-hypoxia activity of HPN derivatives containing lipophilic long chains.

To design and synthesize long-chain substituted 2-[(4'-hydroxyethoxy) phenyl]-4,4,5,5-tetramethyl-2-imidazoline-1-oxyl 3-oxide (HPN) derivatives with enhanced anti-hypoxic activity. HPN derivatives 1, 3, 5 containing lipophilic long chains were synthesized via the alkylation of HPN with 6-bromohexan-1-ol, ethyl 6-bromohexanoate or 6-bromohexane, respectively using acetonitrile as the solvent and K 2CO 3 as the acid-binding agent at 60 ℃. Derivative 2 was synthesized via hydrolysis reactions of derivative 1 in the NaOH/CH 3OH/H 2O system. Using dichloromethane as the solvent and N, N'-diisopropylcarbodiimide as the dehydrating agent, HPN underwent esterification with hexanoic acid to obtain derivative 4. The structures of derivatives 1-5 were characterized by infrared spectroscopy, electron paramagnetic resonance and high resolution mass spectrometry. The purities of derivatives were detected by high performance liquid chromatography, and the lipid solubilities of derivatives were evaluated by calculating the oil-water partition coefficients (log P). Anti-hypoxia activities of HPN and its long-chain lipophilic derivatives 1-5 were evaluated using normobaric hypoxia test and acute decompression hypoxia test. The structures of the derivatives were confirmed by infrared spectroscopy, electron paramagnetic resonance and high resolution mass spectroscopy. The yields of target derivatives were all above 92%, and the purities were all above 96%. The log P values of derivatives 1-5 were 2.78, 2.00, 2.04, 2.88 and 3.10, which were higher than that of HPN (0.97). Derivatives 1-5 significantly prolonged the survival time of mice at the dose of 0.3 mmol/kg in normobaric hypoxic test and reduced the mortality rate of acute decompression hypoxic mice to 60%, 70%, 60%, 70% and 40%, respectively. The synthesis of derivatives 1-5 is convenient, and the yield is high. The synthesized derivatives especially derivative 5 show anti-hypoxic activity similar to or better than HPN at lower doses.

Preparation of meloxicam-salicylic acid co-crystal and its application in the treatment of rheumatoid arthritis

Meloxicam is a non-steroidal anti-inflammatory drug that can selectively inhibit cyclooxygenase 2 (COX-2), showing high anti-inflammatory activity, low gastrointestinal and renal side effects. However, the low solubility and slow dissolution rate limit its role in rapid pain relief. In this paper, using meloxicam as the active drug molecule and salicylic acid as the co-crystal former, the meloxicam-salicylic acid co-crystal (MLX-SLC CoC) was prepared by the reaction crystallization method. The co-crystal was characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The dissolution curve of the co-crystal was determined, and the result showed that the formation of drug co-crystal enhanced the solubility and dissolution rate of MLX. The oil-water partition coefficient of the MLX-SLC CoC was determined, and the results showed that the oil-water partition coefficient of the co-crystal was similar to that of pure MLX. The gel prepared by MLX-SLC CoC was used to study its in vitro release and transdermal penetration characteristics were investigated, which showed that the transdermal penetration of the drug was increased without affecting its in vitro release. Preparation of gel in the form of MLX-SLC CoC increased the drug concentration in the gel. Finally, the therapeutic effect of the gel on arthritis was preliminarily studied by establishing a rheumatoid arthritis rat model.

Enzymatic glucosylation of citrus flavonoids to enhance their bioactivity and taste as new food additives

Cyclodextrin glucosyltransferase (CGTase) is commonly used to produce cyclodextrins but its utility in flavonoids modification is rarely found. In the present study, an enzymatic transformation of citrus flavonoids by applying CGTase as the catalyst was investigated to produce a number of novel polyglucosylated derivatives from monoglucoside metabolites of citrus flavonoid diglycosides. Under the optimized conditions, the yield of glucosylated products achieved 80%. The water solubility and water partition coefficient of citrus flavonoids before and after the structural modification were compared. The results revealed that the water solubility of the flavonoids modified by glucosylation was significantly increased while the oil-water partition coefficient was just slightly reduced. Moreover, after glucosylation, the products have good anti-inflammatory and antioxidant effects. Interestingly, the taste property (bitterness and sweetness) of the glucosylated products was ameliorated. An evaluation with a Taste-Sensing System showed that the taste of the glucosylated products was strongly correlated with the attached rhamnosyl group (bitter taste) and glucosyl group (sweet taste), indicating that the amelioration of taste of flavonoids could be mainly attributed to the addition of glycosyl groups. The present study demonstrated a novel molecular engineering approach for the enhancement of water solubility and amelioration of taste for some citrus flavonoids, which may have potential applications in the functional food industry.

Displacement characteristics of CO2 flooding in extra-high water-cut reservoirs

Carbon dioxide (CO2) flooding is a widely applied recovery method during the tertiary recovery of oil and gas. A high water saturation condition in reservoirs could induce a ‘water shielding’ phenomenon after the injection of CO2. This would prevent contact between the injected gas and the residual oil, restricting the development of the miscible zone. A micro-visual experiment of dead-end models, used to observe the effect of a film of water on the miscibility process, indicates that CO2 can penetrate the water film and come into contact with the residual oil, although the mixing is significantly delayed. However, the dissolution loss of CO2 at high water-cut conditions is not negligible. The oil-water partition coefficient, defined as the ratio of CO2 solubility in an oil-brine/two-phase system, keeps constant for specific reservoir conditions and changes little with an injection gas. The NMR device shows that when CO2 flooding follows water flooding, the residual oil decreases—not only in medium and large pores but also in small and micro pores. At levels of higher water saturation, CO2 displacement is characterized initially by a low oil production rate and high water-cut. After the CO2 breakthrough, the water-cut decreases sharply and the oil production rate increases gradually. The response time of CO2 flooding at high water-cut reservoirs is typically delayed and prolonged. These results were confirmed in a pilot test for CO2 flooding at the P1-1 well group of the Pucheng Oilfield. Observations from this pilot study also suggest that a larger injection gas pore volume available for CO2 injection is required to offset the dissolution loss in high water saturation conditions.

Oil–water partition coefficient preparation and detection in the dihydroartemisinin self-emulsifying drug delivery system

BackgroundThe aim of the present study is to increase the solubility of dihydroartemisinin (DHA) using the self-emulsifying drug delivery system (SEDDS).MethodsWe first conducted solubility test and ternary phase diagram, then, in order to optimize the formulation of the DHA self-emulsifying agent, the design mixture method was selected in the design expert software. Next, optimal prescription validation and preliminary formulation evaluation were conducted. By comparing the oil–water partition coefficient in vitro, the improvement of the in vivo osmotic absorption of DHA via self-emulsification was evaluated.ResultsThe optimal prescription ratio of oleic acid polyethylene glycol glyceride, polyoxyethylene hydrogenated castor oil, and diethylene glycol monoethyl ether in the DHA self-emulsifying preparation = 0.511:0.2:0.289 (w/w/w), with a drug-loading capacity of 26.3634 mg/g, solubility of 2.5448 mg/ml, and self-emulsification time of 230 s. The solubility self-emulsification was approximately 20.52 × higher in DHA than in the crude drug. The self-emulsification could improve DHA permeability and promoting in vivo DHA absorption.ConclusionThe DHA SEDDS could significantly improve DHA solubility and in vivo absorption.

Accurate Physical Property Predictions via Deep Learning.

Neural networks and deep learning have been successfully applied to tackle problems in drug discovery with increasing accuracy over time. There are still many challenges and opportunities to improve molecular property predictions with satisfactory accuracy even further. Here, we proposed a deep-learning architecture model, namely Bidirectional long short-term memory with Channel and Spatial Attention network (BCSA), of which the training process is fully data-driven and end to end. It is based on data augmentation and SMILES tokenization technology without relying on auxiliary knowledge, such as complex spatial structure. In addition, our model takes the advantages of the long- and short-term memory network (LSTM) in sequence processing. The embedded channel and spatial attention modules in turn specifically identify the prime factors in the SMILES sequence for predicting properties. The model was further improved by Bayesian optimization. In this work, we demonstrate that the trained BSCA model is capable of predicting aqueous solubility. Furthermore, our proposed method shows noticeable superiorities and competitiveness in predicting oil–water partition coefficient, when compared with state-of-the-art graphs models, including graph convoluted network (GCN), message-passing neural network (MPNN), and AttentiveFP.

Efficient demulsification of cationic polyacrylate for oil-in-water emulsion: Synergistic effect of adsorption bridging and interfacial film breaking

The development of reverse demulsifier is an urgent need for the increasing amount of produced liquid in oilfield. Synthesis of reverse demulsifier containing multiple characteristics is an effective method. In view of this, this study reports a series of cationic polyacrylates as the reverse demulsifiers, which were prepared by using 3-chloro-1-propanol to modify the copolymer of acrylate and N-[3-(dimethylamino) propyl] methacryamide (DMAPMA). The properties and performance tests showed that the PMD1 prepared by using methyl acrylate (MA) as monomer (mass ratio of MA to DMAPMA was 2:1) has well water solubility, high interfacial activity, and the best demulsification efficiency. For treating the produced liquid from an offshore oilfield, demulsification efficiency of PMD1 was 94.7% with 50 mg/L dosage, which was much higher than that of the reagent in use (15.7%). Furthermore, the demulsification mechanism of PMD1 was studied by oil-water partition coefficient experiment, zeta potential measurement, optical tweezers method, elastic modulus measurement, and coalescence kinetics experiment. Prominent demulsification ability of PMD1 was attributed to the synergistic effect of adsorption bridging via cationic group and oil/water interfacial film breaking by acrylate group. The cationic polyacrylate combines the advantages of polyacrylate and polycation reverse demulsifiers, which display a great application prospect in the petroleum industry.

Self-assembly of Fmoc-amino acids in capillary confined space forming a parallel ordered fiber network for application in vascularization.

Matrices formed by self-assembly of amino acids and their derivatives are suitable for cell spreading, migration and proliferation, and widely used in tissue engineering and organ regeneration, due to the biological endogenous molecules and weak intermolecular forces. The self-assembly process is not only affected by dynamic and thermodynamic factors, but also the assembled space. In this work, capillary tubes with different diameters are chosen to mimic a confined environment and the effect of capillary space on the self-assembly behavior of Fmoc-amino acids with different oil-water partition coefficients (log P) was investigated. The amino acids can form special morphologies and structures through the limitation of the Brownian motion and the template effect exerted by a confined environment. Meanwhile, the obtained parallel ordered fiber network was applied to mimic the extracellular matrix (ECM) and support the adhesion and proliferation of monolayer flat epithelial cells (HUVECs). We believe that the exploration of the self-assembly of amino acids in confined space can promote the understanding of the supramolecular self-assembly mechanism and offer a great opportunity in building the specific structures of vessels or tissues in vitro.

An analysis of the biopharmaceutical behaviour of proton pump inhibitors with different physicochemical properties

At present, little information on the biopharmaceutical behaviour of proton pump inhibitors (PPIs) describing their absorption and biodistribution in vivo has been reported because the extreme instability of PPIs in the gastrointestinal environment makes it difficult to analyze such behaviour. In this work, a modified rat in situ intestinal perfusion model was employed to investigate absorption in the gastrointestinal tract and subsequent biodistribution of several PPIs (ilaprazole, esomeprazole and rabeprazole), which have different physicochemical properties. Our data indicated that PPIs exhibited significantly enhanced absorption rates in the whole intestine, including the duodenum, jejunum, ileum and colon, corresponding to the increase in the oil-water partition coefficient (LogP). PPIs and corresponding salt types showed no obvious differences in absorption, implying that solubility changes in the PPI have little effect on its absorption in the gastrointestinal tract. Among these PPIs, ilaprazole presented a more stable intestinal absorption behaviour, as well as more distribution and longer residence time in the stomach by HPLC-MS/MS analysis and radioactivity counts after 14C radiolabelling. These results may be useful information for PPI optimization and oral formulation design.

The Mechanism Action of German Chamomile (Matricaria recutita L.) in the Treatment of Eczema: Based on Dose–Effect Weight Coefficient Network Pharmacology

To determine the active ingredients in German chamomile volatile oil and the mechanism of action in the treatment of eczema, this study used two parameters (ingredient content and oil–water partition coefficient) and established a new network pharmacology method based on the dose–effect weight coefficient. Through the new network pharmacology method, we found that German chamomile volatile oil regulated T-cell lymphatic subpopulations to inhibit the Th17 cell differentiation signaling pathway. This resulted in a reduction of interleukin 17 (IL-17), thereby inhibiting the activation of the nuclear factor kappa beta (NF-κB) and MAPK pathways, decreasing the secretion of the pro-inflammatory factors (tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6)), and reducing inflammation. In this study, a new dose–effect relationship synergistic network pharmacology method was established to provide a new method for the screening of effective ingredients and pathways of drugs, and to provide a basis for the follow-up studies of German chamomile volatile oil in the treatment of eczema.