Attenuation of Intestinal Absorption by Major Efflux Transporters: Quantitative tools and strategies using Caco-2 model

Efflux transporters expressed in the apical membrane of intestinal enterocytes have been implicated in drug oral absorption. The current study presents a strategy and tools to quantitatively predict efflux impact on oral absorption for new chemical entities (NCEs) in early drug discovery. Sixty-two marketed drugs with human absorption data were evaluated in the Caco-2 bidirectional permeability assay and subjected to specific transporter inhibition. A four-zone graphical model was developed from apparent permeability and efflux ratio to quickly identify compounds whose efflux activity may distinctly influence human absorption. NCEs in “zone 4” will likely have efflux as a barrier for oral absorption and further mechanistic studies are required. The previously described absorption quotient (AQ) was integrated into our data analysis towards a model to project the impact of physicochemical properties on drug absorption. In this way chemistry strategy may be focused on passive permeability or efflux activity or both. We introduced a new substrate classification parameter, transporter substrate index (TSI). More quantitative than efflux ratio and more widely applicable than AQ, TSI considered both in vitro and in vivo outcomes. Its application ranged from addressing the challenge of overlapping substrate specificity to projecting the role of transporter(s) on exposure or potential DDI risk

Characterization and Application of Magnetic Biochars from Corn Stalk by Pyrolysis and Hydrothermal Treatment

Two novel magnetic biochar composites (FeC-H and FeC-P) were synthesized using corn stalks and ferrous sulfate through hydrothermal method and traditional pyrolysis, respectively. The samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), vibrating sample magnetometer, and particle size analyzer. Batch experiments were conducted to investigate the ability of those samples to absorb aqueous phosphate. FeC-H had lower surface area than FeC-P, but more hydrophilic functional groups were detected on the rough surface of FeC-H. The impregnated iron was present as Fe3O4 in the prepared magnetic biochar composites. The introduced Fe3O4 resulted in high performance of magnetic separation and also played the role as adsorption sites for phosphate. FeC-H and FeC-P demonstrated higher sorption capacity than bare Fe3O4 due to the highly dispersed and smaller crystalline sizes of Fe3O4 particles loaded in corn stalk derived-biochar support. FeC-H had the best performance, with Langmuir adsorption capacity as high as 5.04 mg/g for phosphate. These results indicate that the magnetic biochar composites prepared from corn stalks by hydrothermal method (FeC-H) have potential as a high-efficiency and cost-effective adsorbent for phosphorus removal from wastewater

Towards prediction of in vivo exposure from a permeability perspective using a 96-well Caco-2 assay

In this study we systematically validated a reproducible 96-well Caco-2 assay via an extended test set of 93 marketed drugs consisting of diverse transport mechanisms and quantified by LC/MS/MS. We sought to investigate the predictive utility of the widely-accepted Caco-2 permeability assay while dealing with the impact of solubility and recovery on challenging discovery compounds. We observed that paracellular compounds could be flagged by absorptive permeability (logPapp(A-B) <-5.5 cm/s) and physicochemical property space (clogP <1). An examination of 8000 Novartis discovery compounds revealed 14% were rejected for testing based on low aqueous solubility, while 13% were subject to low recovery (<30%). Compound loss in the assay was examined using a comparison between cell monolayer and artificial membrane (PAMPA), while bovine serum albumin (0.5% BSA in both donor and acceptor compartments) was utilized to improve recovery in the assay. The caveat to using Vitamin E TPGS to reduce solubility drop-offs was evaluated. The second focus of this study was to investigate the advantages and limitations of the current 96-well Caco-2 screening assay for predicting in vivo exposure from the permeability perspective in the drug discovery stage. Caco-2 measurements for compounds with high aqueous solubility and low in vitro metabolic clearance were compared to 88 in vivo rat bioavailability studies. Despite the challenges posed by discovery compounds with sub-optimal physicochemical properties, Caco-2 data successfully projected low exposure. This platform set the stage for mechanistically evaluating subsets of compounds towards improving in vitro-in vivo correlations

Survey on Fertility of Tea Garden Soil in Meizhou Region

Survey on fertility of tea garden soil in Meizhou region indicates that tea garden soil has strong acidity; organic matter content remains at medium level; there is a severe lack oof available content of nitrogen (N), phosphorus (P) and potassium (K); available calcium (Ca) and magnesium (Mg) content is also insufficient; available sulfur (S) is abundant. In the management of tea cultivation, it is recommended to supplement organic fertilizer, balance the application of NPK fertilizer, and adequately alleviate shortage of Ca and Mg element, to guarantee high and stable yield of tea

A CpG-Oligodeoxynucleotide Suppresses Th2/Th17 Inflammation by Inhibiting IL-33/ST2 Signaling in Mice from a Model of Adoptive Dendritic Cell Transfer of Smoke-Induced Asthma

Tobacco smoke exposure is a major environmental risk factor that facilitates the development and progression of asthma. Our previous study showed that CpG oligodeoxynucleotide (CpG-ODN) inhibits thymic stromal lymphopoietin (TSLP)-dendritic cells (DCs) to reduce Th2/Th17-related inflammatory response in smoke-related asthma. However, the mechanism underlying CpG-ODN -downregulated TSLP remains unclear. A combined house dust mite (HDM)/cigarette smoke extract (CSE) model was used to assess the effects of CpG-ODN on airway inflammation, Th2/Th17 immune response, and amount of IL-33/ST2 and TSLP in mice with smoke-related asthma induced by adoptive transfer of bone-marrow-derived dendritic cells (BMDCs) and in the cultured human bronchial epithelium (HBE) cells administered anti-ST2, HDM, and/or CSE. In vivo, compared to the HDM alone model, the combined HDM/CSE model had aggravated inflammatory responses, while CpG-ODN attenuated airway inflammation, airway collagen deposition, and goblet cell hyperplasia and reduced the levels of IL-33/ST2, TSLP, and Th2/Th17-cytokines in the combined model. In vitro, IL-33/ST2 pathway activation promoted TSLP production in HBE cells, which could be inhibited by CpG-ODN. CpG-ODN administration alleviated Th2/Th17 inflammatory response, decreased the infiltration of inflammatory cells into the airway, and improved the remodeling of smoke-related asthma. The underlying mechanism may be that CpG-ODN inhibits the TSLP-DCs pathway by downregulating the IL-33/ST2 axis

A CpG-Oligodeoxynucleotide Suppresses Th2/Th17 Inflammation by Inhibiting IL-33/ST2 Signaling in Mice from a Model of Adoptive Dendritic Cell Transfer of Smoke-Induced Asthma

Tobacco smoke exposure is a major environmental risk factor that facilitates the development and progression of asthma. Our previous study showed that CpG oligodeoxynucleotide (CpG-ODN) inhibits thymic stromal lymphopoietin (TSLP)-dendritic cells (DCs) to reduce Th2/Th17-related inflammatory response in smoke-related asthma. However, the mechanism underlying CpG-ODN -downregulated TSLP remains unclear. A combined house dust mite (HDM)/cigarette smoke extract (CSE) model was used to assess the effects of CpG-ODN on airway inflammation, Th2/Th17 immune response, and amount of IL-33/ST2 and TSLP in mice with smoke-related asthma induced by adoptive transfer of bone-marrow-derived dendritic cells (BMDCs) and in the cultured human bronchial epithelium (HBE) cells administered anti-ST2, HDM, and/or CSE. In vivo, compared to the HDM alone model, the combined HDM/CSE model had aggravated inflammatory responses, while CpG-ODN attenuated airway inflammation, airway collagen deposition, and goblet cell hyperplasia and reduced the levels of IL-33/ST2, TSLP, and Th2/Th17-cytokines in the combined model. In vitro, IL-33/ST2 pathway activation promoted TSLP production in HBE cells, which could be inhibited by CpG-ODN. CpG-ODN administration alleviated Th2/Th17 inflammatory response, decreased the infiltration of inflammatory cells into the airway, and improved the remodeling of smoke-related asthma. The underlying mechanism may be that CpG-ODN inhibits the TSLP-DCs pathway by downregulating the IL-33/ST2 axis