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Highlights: What are the main findings? The validated method was robust, reliable, and sensitive for quantifying ABZ, ABZ-OX, ABZ-ON, and PR simultaneously from the plasma and dried blood spots. The method is well suited for therapeutic drug monitoring due to its high sensitivity, minimal sample volume requirement, and the ability for remote collection. What is the implication of the main finding? Dried blood spot (DBS) analysis represents an alternative sampling technique over conventional blood-sampling methods, particularly for sample collection, enabling a non-clinical setup without requiring special equipment or trained healthcare personnel. Additionally, it minimizes the solvent volume and analysis time and reduces transportation and storage needs. Millions of individuals throughout the world suffer from lymphatic filariasis (LF), which is a morbid disease caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori. These infections belong to tissue-invading nematodes and are one of the major neglected tropical diseases that often result in permanent and enduring disability among individuals in endemic regions. Due to combination therapy, LF eradication has drastically decreased infections globally. The development of blood micro-sampling techniques allowing precise quantitation of drugs in blood would facilitate pharmacokinetic (PK) studies in remote populations. Therefore, an LC-MS/MS bioanalytical method was utilized to analyze albendazole (ABZ), albendazole sulfone (ABZ-ON), albendazole sulfoxide (ABZ-OX), and probenecid (PR) in plasma and dried blood spots. Solid-phase extraction was utilized to extract the analyte from both plasma and blood-spiked DBS. Analytes of interest were eluted with a gradient mobile system using 0.05% formic acid in water (A) and 0.05% formic acid in methanol (B) and separated using a reversed-phase Acquity ®BEH C18 UPLC column (100 × 2.1 mm, 1.7 µm). Precision and accuracy at each QC level were within the acceptable limit, i.e., ±15% for all analytes in both the matrices. Tests for stability under laboratory and storage conditions indicated that no notable changes were observed for plasma and DBS. The LC-MS/MS method demonstrated its capability to consistently identify all target analytes (ABZ, ABZ-ON, ABZ-OX, and PR) at low concentrations, even at the small specimen volumes obtained from DBS cards. This confirms the efficacy and durability of DBS cards as a micro-sampling technique. Moreover, it enhances collection efforts for therapeutic drug monitoring in remote locations for patients infected with lymphatic filariasis. [ABSTRACT FROM AUTHOR]

The differences among individual eicosanoids in eliciting different physiological and pathological responses are largely unknown because of the lack of valid and simple analytical methods for the quantification of individual eicosanoids and their metabolites in serum, sputum and bronchial alveolar lavage fluid (BALF). Therefore, a simple and sensitive LC-MS/MS method for the simultaneous quantification of 34 eicosanoids in human serum, sputum and BALF was developed and validated. This method is valid and sensitive with a limit of quantification ranging from 0.2 to 3 ng/mL for the various analytes, and has a large dynamic range (500 ng/mL) and a short run time (25 min). The intra- and inter-day accuracy and precision values met the acceptance criteria according to US Food and Drug Administration guidelines. Using this method, detailed eicosanoid profiles were quantified in serum, sputum and BALF from a pilot human study. In summary, a reliable and simple LC-MS/MS method to quantify major eicosanoids and their metabolites was developed and applied to quantify eicosanoids in human various fluids, demonstrating its suitability to assess eicosanoid biomarkers in human clinical trials.

Osteosarcoma (OS) is a primary malignant bone tumor characterized by frequent metastasis, rapid disease progression, and a high rate of mortality. Treatment options for OS have remained largely unchanged for decades, consisting primarily of cytotoxic chemotherapy and surgery, thus necessitating the urgent need for novel therapies. Tropolones are naturally occurring seven‐membered non‐benzenoid aromatic compounds that possess antiproliferative effects in a wide array of cancer cell types. MO‐OH‐Nap is an α‐substituted tropolone that has activity as an iron chelator. Here, we demonstrate that MO‐OH‐Nap activates all three arms of the unfolded protein response (UPR) pathway and induces apoptosis in a panel of human OS cell lines. Co‐incubation with ferric chloride or ammonium ferrous sulfate completely prevents the induction of apoptotic and UPR markers in MO‐OH‐Nap‐treated OS cells. MO‐OH‐Nap upregulates transferrin receptor 1 (TFR1) protein levels, as well as TFR1, divalent metal transporter 1 (DMT1), iron‐regulatory proteins (IRP1, IRP2), ferroportin (FPN), and zinc transporter 14 (ZIP14) transcript levels, demonstrating the impact of MO‐OH‐Nap on iron‐homeostasis pathways in OS cells. Furthermore, MO‐OH‐Nap treatment restricts the migration and invasion of OS cells in vitro. Lastly, metabolomic profiling of MO‐OH‐Nap‐treated OS cells revealed distinct changes in purine and pyrimidine metabolism. Collectively, we demonstrate that MO‐OH‐Nap‐induced cytotoxic effects in OS cells are dependent on the tropolone's ability to alter cellular iron availability and that this agent exploits key metabolic pathways. These studies support further evaluation of MO‐OH‐Nap as a novel treatment for OS. [ABSTRACT FROM AUTHOR]

The outer mycomembrane of Mycobacterium tuberculosis and related pathogens is a robust permeability barrier that protects against antibiotic treatment. Here, we demonstrate that synthetic analogues of the mycomembrane biosynthetic precursor trehalose monomycolate bearing truncated lipid chains increase permeability of Mycobacterium smegmatis cells and sensitize them to treatment with the first-line anti-tubercular drug rifampicin. The reported strategy may be useful for enhancing entry of drugs and other molecules to mycobacterial cells, and represents a new way to study mycomembrane structure and function. [ABSTRACT FROM AUTHOR]

Background: Ivermectin (IVM) is a broad–spectrum anthelmintic drug used to treat diseases caused by filarial worms, such as onchocerciasis and lymphatic filariasis (LF). IVM is part of a triple–drug therapy used by the Mass Drug Administration (MDA) as a preventive strategy to eradicate LF in sub–Saharan Africa. The drug shows high variability in drug exposure in previous pharmacokinetic studies. This study aims to build a population pharmacokinetic (PopPK) model to identify and quantify the possible sources of the variability of IVM exposure after a single–oral dose in LF–infected subjects and healthy individuals. Methodology / Principal findings: In this analysis, 724 samples were collected from treatment–naïve Wuchereria bancrofti–infected (n = 32) and uninfected (n = 24) adults living in Côte d'Ivoire who had received one dose of IVM as a part of triple–drug therapy. PopPK analysis was conducted using Phoenix NLME 8.3 software. The Monte Carlo simulation based on the final model was performed to simulate drug exposure among different dosing groups (200 μg/kg, 18 mg, and 36 mg). A two–compartment model with zero–order dose input into the absorption compartment with a lag time function followed by first–order absorption and linear elimination best described the IVM's pharmacokinetic (PK) parameters. The final model identifies that the PK parameters of IVM are not affected by LF infection. Sex was a significant covariate on the peripheral volume of distribution (Vp/F, 53% lower in men than in women). IVM drug exposure shows linear pharmacokinetic behavior among the simulated dosing groups with similar drug exposure based on sex. Conclusion/Significance: We have developed a PopPk model to describe and identify possible sources of the variability of IVM exposure. To our knowledge, this is the first PopPK study of IVM in patients with LF. Trial registration: NCT02845713; NCT03664063 Author summary: Ivermectin has been shown to be a valuable tool in mass drug administration campaigns against lymphatic filariasis. The drug shows high variability in drug exposure in previous pharmacokinetic studies. Variability in drug exposure can lead to either a higher exposure with the potential for toxic effects or a lower exposure that may result in treatment failure. Identifying and quantifying the source of high variability using non–linear mixed effects modeling is crucial for future dosing recommendations that seek to maximize therapeutic benefit while minimizing toxicity risks. In this study, the variability of IVM exposure after a single oral dose was investigated with a population pharmacokinetic model using data from Lymphatic filariasis infected subjects and healthy individuals. [ABSTRACT FROM AUTHOR]

Rab GTPases are critical regulators of protein trafficking in the cell. To ensure proper cellular localization and function, Rab proteins must undergo a posttranslational modification, termed geranylgeranylation. In the isoprenoid biosynthesis pathway, the enzyme geranylgeranyl diphosphate synthase (GGDPS) generates the 20‐carbon isoprenoid donor (geranylgeranyl pyrophosphate [GGPP]), which is utilized in the prenylation of Rab proteins. We have pursued the development of GGDPS inhibitors (GGSI) as a novel means to target Rab activity in cancer cells. Osteosarcoma (OS) and Ewing sarcoma (ES) are aggressive childhood bone cancers with stagnant survival statistics and limited treatment options. Here we show that GGSI treatment induces markers of the unfolded protein response (UPR) and triggers apoptotic cell death in a variety of OS and ES cell lines. Confirmation that these effects were secondary to cellular depletion of GGPP and disruption of Rab geranylgeranylation was confirmed via experiments using exogenous GGPP or specific geranylgeranyl transferase inhibitors. Furthermore, GGSI treatment disrupts cellular migration and invasion in vitro. Metabolomic profiles of OS and ES cell lines identify distinct changes in purine metabolism in GGSI‐treated cells. Lastly, we demonstrate that GGSI treatment slows tumor growth in a mouse model of ES. Collectively, these studies support further development of GGSIs as a novel treatment for OS and ES. [ABSTRACT FROM AUTHOR]