The effect of molecular weight/lipophilicity on clearance of organic compounds from lungs

Uncovering the toxicity mechanisms of a series of carboxylic acids in liver cells through computational and experimental approaches

Hepatotoxicity poses a significant concern in drug design due to the potential liver damage that can be caused by new drugs. Among common manifestations of hepatotoxic damage is lipid accumulation in hepatic tissue, resulting in liver steatosis or phospholipidosis. Carboxylic derivatives are prone to interfere with fatty acid metabolism and cause lipid accumulation in hepatocytes. This study investigates the toxic behaviour of 24 structurally related carboxylic acids in hepatocytes, specifically their ability to cause accumulation of fatty acids and phospholipids. Using high-content screening (HCS) assays, we identified two distinct lipid accumulation patterns. Subsequently, we developed structure-activity relationship (SAR) and quantitative structure-activity relationship (QSAR) models to determine relevant molecular substructures and descriptors contributing to these adverse effects. Additionally, we calculated physicochemical properties associated with lipid accumulation in hepatocytes and examined their correlation with our chemical structure characteristics. To assess the applicability of our findings to a wide range of chemical compounds, we employed two external datasets to evaluate the distribution of our QSAR descriptors. Our study highlights the significance of subtle molecular structural variations in triggering hepatotoxicity, such as the presence of nitrogen or the specific arrangement of substitutions within the carbon chain. By employing our comprehensive approach, we pinpointed specific molecules and elucidated their mechanisms of toxicity, thus offering valuable insights to guide future toxicology investigations.

Green synthesis, radioiodination and in vivo biodistribution of 5-(2-hydroxyphenyl)-2,4-dihydro-3H-pyrazol-3-one derivatives as potential candidates for lung imaging

Lung targeting was developed by synthesising pyrazolone derivatives 6a-f under solvent-free and thermal conditions by reacting azo coumarins 4a-c with hydrazines 5a and b using maltose as a biodegradable catalyst. Different spectral data characterized the synthesized agents as proton-NMR, FT-IR, and mass spectra. Direct radioiodination with iodine-131 was performed and optimized to reach the highest radiochemical purities (92 ± 0.47 to 98 ± 0.21%) using chloramine-T, a moderate oxidizing agent. The 131I-pyrazolone derivatives were confirmed based on HRMS. Furthermore, radioiodinated nitro-derivatives accumulated well in the lung of normal mice during in vivo evaluation, and the better uptake was for nitrophenyl-derivative 7f, about 30.06 ± 0.04% at 30 min after injection. Consequently, synthesized radioiodinated derivatives may be employed as prospective tracers for lung perfusion scans.

Transforming the Chemical Structure and Bio-Nano Activity of Doxorubicin by Ultrasound for Selective Killing of Cancer Cells

Reconfiguring the structure and selectivity of existing chemotherapeutics represents an opportunity for developing novel tumor-selective drugs. Here, as a proof-of-concept, the use of high-frequency sound waves is demonstrated to transform the nonselective anthracycline doxorubicin into a tumor selective drug molecule. The transformed drug self-aggregates in water to form ≈200 nm nanodrugs without requiring organic solvents, chemical agents, or surfactants. The nanodrugs preferentially interact with lipid rafts in the mitochondria of cancer cells. The mitochondrial localization of the nanodrugs plays a key role in inducing reactive oxygen species mediated selective death of breast cancer, colorectal carcinoma, ovarian carcinoma, and drug-resistant cell lines. Only marginal cytotoxicity (80-100% cell viability) toward fibroblasts and cardiomyocytes is observed, even after administration of high doses of the nanodrug (25-40 µg mL^-1 ). Penetration, cytotoxicity, and selectivity of the nanodrugs in tumor-mimicking tissues are validated by using a 3D coculture of cancer and healthy cells and 3D cell-collagen constructs in a perfusion bioreactor. The nanodrugs exhibit tropism for lung and limited accumulation in the liver and spleen, as suggested by in vivo biodistribution studies. The results highlight the potential of this approach to transform the structure and bioactivity of anticancer drugs and antibiotics bearing sono-active moieties.

Development of a Novel Quantitative Structure-Activity Relationship Model to Accurately Predict Pulmonary Absorption and Replace Routine Use of the Isolated Perfused Respiring Rat Lung Model

Purpose

We developed and tested a novel Quantitative Structure-Activity Relationship (QSAR) model to better understand the physicochemical drivers of pulmonary absorption, and to facilitate compound design through improved prediction of absorption. The model was tested using a large array of both existing and newly designed compounds.

Methods

Pulmonary absorption data was generated using the isolated perfused respiring rat lung (IPRLu) model for 82 drug discovery compounds and 17 marketed drugs. This dataset was used to build a novel QSAR model based on calculated physicochemical properties. A further 9 compounds were used to test the model’s predictive capability.

Results

The QSAR model performed well on the 9 compounds in the “Test set” with a predicted versus observed correlation of R² = 0.85, and >65% of compounds correctly categorised. Calculated descriptors associated with permeability and hydrophobicity positively correlated with pulmonary absorption, whereas those associated with charge, ionisation and size negatively correlated.

Conclusions

The novel QSAR model described here can replace routine generation of IPRLu model data for ranking and classifying compounds prior to synthesis. It will also provide scientists working in the field of inhaled drug discovery with a deeper understanding of the physicochemical drivers of pulmonary absorption based on a relevant respiratory compound dataset.

Synthesis and anti-microbial activity of isothiosemicarbazones and cyclic analogues

It is known that some derivatives of both thiourea and thiosemicarbazide exhibit potent anti-microbial activity. In order to investigate the effects on the biological properties of structural modifications of such structures, we have synthesised and studied some arylidenisothiosemicarbazones. In this paper we report on the synthesis and structure-activity relationships of some isothiosemicarbazones, where the arylidene group has been replaced with a cycloalkyl group and the sulfur atom has been either differently substituted or enclosed in a thiazole ring.

Cytokine profile of human bronchoalveolar macrophages and bronchial epithelial cells in response to inhalation particles of the cyclosporine derivative IMM 125

Administration of antiasthmatic drugs in the form of inhalation particles may alter the cytokine network in the airways, independently of their pharmacological actions. Changes induced by drugs not well tolerated may potentially contribute to the immunopathology of the disease, a strongly undesirable effect. In this study, cell viability assays and characterization of the cellular profile of cytokines and chemokines were performed in order to investigate the response of human bronchoalveolar macrophages and bronchial epithelial cells in culture to inhalation particles of the cyclosporine derivative IMM 125. Interleukin 1beta (IL-1beta), tumor necrosis factor alpha (TNFalpha), and IL-8 were assayed by enzyme-linked immunosorbent assay (ELISA) in the supernatants of bronchoalveolar macrophages, and RANTES, granulocyte--macrophage colony-stimulating factor (GM-CSF), and IL-8 in those of bronchial epithelial cells. Cells were studied both under basal and stimulated conditions (lipopolysaccharide and TNFalpha were used for activating macrophages and epithelial cells, respectively). The immunosuppressant FK 506 and the glucocorticoid Budesonide served as comparison. IMM 125 did not affect cell viability (except at high concentrations and long time periods). Moreover, IMM 125 did not induce an increase in the secretion of any of the cytokines and chemokines measured with respect to nontreated cells, except for a slight increase in IL-8, an effect that was also observed for FK 506, Budesonide, and inert latex particles, and was therefore regarded as nonspecific. Furthermore, IMM 125 significantly decreased the secretion of TNFalpha, IL-1beta by macrophages, and GM-CSF by epithelial cells, suggesting an antiinflammatory potential. In conclusion, the present in vitro results point to a good tolerance of human airways to IMM 125 inhalation particles.

The retention of polycyclic aromatic hydrocarbons in the bronchial airways and in the alveolar region--a theoretical comparison

Several experiments indicate that physical transport phenomena such as molecular diffusion and partitioning between aqueous and lipid phases have a profound influence on the pulmonary retention of polycyclic aromatic hydrocarbons (PAHs). Because the average distance of diffusion between the air interface and the capillary blood is only about 0.5 microm in the alveoli, whereas in the bronchi it probably exceeds 50 microm, there should be a fundamental difference between the bronchial airways and the alveolar region in the retention of PAHs. A theoretical model was developed to simulate the retention of lipophilic substances in the two regions of the lung. Results show that a substance like benzo[a]pyrene, a PAH, may be retained for hours in the bronchi, compared to less than 1 min in the alveoli. This predicted dramatic difference in retention could explain the characteristic, biphasic pattern in the pulmonary clearance of PAHs observed in many animal experiments, but more importantly, it could also explain the fact that human lung cancers occur predominantly in the bronchi, although only a small fraction of inhaled particles carrying PAHs are deposited there.