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Aim: Proteolysis targeting chimeras (PROTACs) exhibit a unique and promising pharmacology. However, this comes with molecular properties exceeding the 'drug-like' rule of five chemical space, which often limits gastrointestinal absorption. This in vivo study aimed to investigate the contribution of luminal and plasma stability, intestinal effective permeability, P-glycoprotein (P-gp) efflux, and bile excretion, on the rat intestinal absorption and systemic exposure of two PROTACs, ARV-110 (812 Da, LogD_7.4 4.8) and ARV-471 (724 Da, LogD_7.4 4.6).

Methods: Luminal stability and effective intestinal permeability were determined directly from luminal disappearance using single-pass intestinal perfusion, with and without a protease inhibitor, or a P-gp/Cytochrome P450 CYP3A inhibitor (ketoconazole) in rats. Plasma stability was tested by in vitro incubations. Intestinal absorption, systemic exposure, and biliary excretion were examined after intraduodenal and intravenous dosing with ketoconazole or the P-gp selective inhibitor (encequidar).

Results and discussion: Both PROTACs were degraded in the intestinal lumen and in plasma by peptidases. The intestinal effective permeability in rats was moderate for ARV-110 (0.62 x 10^-4 cm/s) and low for ARV-471 (0.23 x 10^-4 cm/s). P-gp inhibition increased the permeability 1.6-and 2.3-fold for ARV-110 and ARV-471, respectively. After intraduodenal dosing with the P-gp inhibitors a corresponding increase in systemic exposure was observed for both PROTACs. There was only a minor difference in the increased systemic exposure induced by the two inhibitors, suggesting that the mechanisms were primarily P-gp inhibition, rather than gut-wall and hepatic extraction. Biliary excretion was a minor pathway and did not affect the absorption and systemic exposure of the PROTACs to a large extent.

Conclusion: In the rat, ARV-110 and ARV-471 were enzymatically degraded in the intestinal lumen and in plasma, and their intestinal permeability and systemic exposure seem to be reduced due to P-gp efflux.

Sodium-glucose co-transporter 2 inhibitors like canagliflozin (CFZ) have shown promise in preventing hyperinsulinemia-associated laminitis in horses, but data on pharmacokinetics, tolerability, and controlled studies are limited. This randomized, open-label, placebo-controlled, crossover study evaluated these aspects of CFZ treatment in eight healthy Standardbred mares. Each horse received single supratherapeutic oral doses of CFZ (1.8 mg/kg or 3.6 mg/kg) and placebo, with a two-week washout between treatments. A graded glucose infusion (GGI) was administered post-treatment to evaluate glucose and insulin responses. Plasma CFZ, glucose, insulin, urinary glucose, serum biochemistry, and urinalysis samples were collected over 72 h post-treatment. For CFZ 1.8 mg/kg, median C_max was 2623 ng/mL, T_max 2.2 h, and T_1/2Z 21.8 h; for 3.6 mg/kg, C_max was 4975 ng/mL, T_max 2.8 h, and T_1/2Z 23.0 h. The pharmacokinetics of CFZ displayed dose-proportionality across the two tested doses. Insulin and glucose responses to a GGI, measured by the area under the concentration-time curve (AUC), were similar between CFZ doses but significantly reduced compared to placebo (p < 0.001). Specifically, mean glucose AUC for CFZ treatments was approximately 14–15 % lower, and mean insulin AUC 22–29 % lower, than for placebo. For CFZ-treated horses, mean urinary glucose concentrations ranged from 277 to 347 mmol/L at 24, 48, and 72 h post-administration, with no significant differences between dose levels. No clinical signs of adverse effects were observed, although a significant increase in GLDH levels compared to placebo (p < 0.05) was observed with the CFZ 3.6 mg/kg dose.

Hepatocellular carcinoma is an aggressive cancer characterized by metabolic reprogramming in lipid-, nucleotide and amino acid metabolism/catabolism and oxidative stress management. This in vitro study investigates the potential cytotoxic and metabolic effects of the novel combination of doxorubicin and atorvastatin, a cholesterol-lowering drug, in the well-characterized Huh-7 cell line. The cytotoxicity of statins and fibrates was assessed through dose-response curves and the half-maximal inhibitory concentration (IC50) for each treatment, both individually and in combination. Synergism was determined using the Chou-Talalay method. Among the tested agents, atorvastatin exhibited the most potent cytotoxicity, with an IC50 of 70.45 µM. When combined with doxorubicin, the IC50 of doxorubicin decreased significantly from 165.25 µM to 26.85 µM, indicating a synergistic effect. Metabolic profiling revealed distinct changes in lipid metabolism, fatty acid oxidation and the carnitine shuttle system, specifically within the combination treatment. The combination treatment also seems to affect oxidative stress management via the urea cycle, polyamine biosynthesis, and catabolism of nucleotides and amino acids. By limiting energy production, while simultaneously disrupting oxidative stress management, this therapy creates a plausible metabolic bottleneck, which may impair cancer cell adaptation to stress and growth. These findings suggest that combining atorvastatin with doxorubicin might enhance treatment efficacy and/or reduce resistance.

Canagliflozin (CFZ) is a sodium-glucose cotransporter-2 inhibitor that has shown promising results as a drug for the treatment of insulin dysregulation in horses. Even though CFZ is used clinically, no pharmacokinetic data has previously been published. In this study, the pharmacokinetics of CFZ after administration of a single oral dose of 1.8 mg/kg in eight healthy Icelandic horses was examined. Additionally, the effect of treatment on glucose and insulin levels in response to a graded glucose infusion was investigated. Plasma samples for CFZ quantification were taken at 0, 0.33, 0.66, 1, 1.33, 1.66, 2, 2.33, 2.66, 3, 3.5, 4, 5, 6, 8, 12, 24, 32, and 48 h post administration. CFZ was quantified using UHPLC coupled to tandem quadrupole mass spectrometry (UHPLC-MS/MS). A non-compartmental analysis revealed key pharmacokinetic parameters, including a median T_max of 7 h, a C_max of 2350 ng/mL, and a t_1/2Z of 28.5 h. CFZ treatment reduced glucose (AUC_GLU, p = 0.001) and insulin (AUC_INS, p = 0.04) response to a graded glucose infusion administered 5 h after treatment. This indicates a rapid onset of action following a single dose in healthy Icelandic horses. No obvious adverse effects related to the treatment were observed.

Background: Lipids such as phosphatidic acids (PAs) and cardiolipins (CLs) present strongly tailing peaks in reversed phase liquid chromatography, which entails low detectability. They are usually analyzed by hydrophilic interaction liquid chromatography (HILIC), which hampers high-throughput lipidomics. Thus, there is a great need for improved analytical methods in order to obtain a broader coverage of the lipidome in a single chromatographic method. We investigated the effect of ammonium bicarbonate (ABC) on peak asymmetry and detectability, in comparison with ammonium formate (AFO) on both a conventional BEH C18 column and an HST-CSH C18 column.

Results: The combination of 2.5 mM ABC buffer pH 8 with an HST-CSH C18 column produced significantly improved results, reducing the asymmetry factor at 10 % peak height of PA 16:0/18:1 from 8.4 to 1.6. Furthermore, on average, there was up to a 54-fold enhancement in the peak height of its [M - H]- ion compared to AFO and the BEH C18 column. We confirmed this beneficial effect on other strongly tailing lipids, with accessible phosphate moieties e.g., cardiolipins, phosphatidylinositol phosphate, phosphatidylinositol bisphosphate, phosphorylated ceramide and phosphorylated sphingosine. Furthermore, we found an increased detectability of phospho- and sphingolipids up to 28 times in negative mode when using an HST-CSH C18 column. The method was successfully applied to mouse liver samples, where previously undetected endogenous phospholipids could be analyzed with improved chromatographic separation.

Significance: In conclusion, the use of 2.5 mM ABC substantially improved the peak shape of PAs and enhanced the detectability of the lipidome in negative mode on an RPLC-ESI-Q-TOF-MS system on both BEH C18 and HSTCSH C18 columns. This method provides a wider coverage of the lipidome with one single injection for future lipidomic applications in negative mode.

Chemically induced, targeted protein degradation with proteolysis targeting chimeras (PROTACs) has shown to be a promising pharmacological strategy to circumvent the poor "druggability" of intracellular targets. However, the favorable pharmacology comes with complex molecular properties limiting the oral bioavailability of these drugs. To foster the translation of PROTACs into the clinics it is of high importance to establish sensitive bioanalytical methods that enable the assessment of absorption, bioavailability, and disposition of PROTACs after oral dosing. In this study, two highly sensitive LC-MS/MS methods (LLOQ = 0.5 ng/mL) were developed and validated for the quantification of bavdeglutamide (ARV-110) and vepdegestrant (ARV-471) in rat plasma. Plasma samples were processed by protein precipitation and separated on a C18 column over a gradient of acetonitrile and water with 0.1 % formic acid. Selected reaction monitoring in positive ESI mode was applied to quantify ARV-110 and ARV-471. Both methods showed linearity, accuracy, and precision as well as matrix effects and carry-over within the predefined acceptance criteria. High stability of the compounds in plasma was demonstrated at long-term storage for seven weeks at-20°C, three freeze-thaw cycles, up to 20 min at room temperature, and as extracts in the autosampler. The plasma concentration-time curves after intravenous and intraduodenal bolus single-dose administrations in rats could be successfully quantified at clinically relevant doses per body weight. The highly sensitive bioanalytical assays presented in this work enable the application of a broad spectrum of in vivo studies to elucidate the oral absorption, bioavailability, and disposition of PROTACs.

BACKGROUND: Preeclampsia complicates 3-5% of all pregnancies and is associated with higher levels of asymmetric (ADMA) and symmetric (SDMA) dimethylarginines. Dimethylarginines are inhibitors of nitric oxide, which is a uterine smooth muscles relaxant. Women with hypertensive disorders experience a shorter labor duration compared to normotensive women. However, very little is known about the possible biochemical mechanisms behind differences in labor duration. In this study we aimed to investigate if women with preeclampsia had higher levels of arginines (ADMA, SDMA and L-arginine) at labor than controls, and also investigate the association between arginines and labor duration.

METHODS: The study was based on data from the Swedish, Uppsala County population-based, prospective cohort BASIC, between 2009 and 2018. Arginines were analyzed by Ultra-High Performance Liquid Chromatography using plasma samples taken at labor from women with preeclampsia (n=47) and normotensive pregnancy (n=90). We also analyzed inflammation markers CRP, TNF-R1, TNF-R2 and GDF-15.

RESULTS: Women with preeclampsia had higher levels of ADMA (p<0.001), SDMA (p<0.001), L-arginine (p<0.001), TNF-R1 (p<0.001), TNF-R2 (p=0.03) and GDF-15 (p<0.01) compared to controls. Further, ADMA and SDMA, not inflammation markers, were negatively correlated to labor duration in preeclampsia. No correlations were observed when comparing arginines and inflammation markers.

CONCLUSIONS: Among women with preeclampsia, our novel findings of higher level of arigines, negative correlation of arginines to duration of labor and absence of correlation of arginines to inflammation markers might support the theory that it is not inflammation but arginines which could be associated with shorter duration of labor in preeclampsia.

Problem: Preterm birth (PTB) is a leading cause of infant mortality and morbidity. The pathogenesis of PTB is complex and involves many factors, including socioeconomy, inflammation and infection. Asymmetric dimethylarginine, ADMA and symmetric dimethylarginine, SDMA are involved in labor as inhibitors of nitric oxide, a known relaxant of the uterine smooth muscles. Arginines are scarcely studied in relation to PTB and we aimed to investigate arginines (ADMA, SDMA and L-arginine) in women with spontaneous PTB and term birth.

Methods of the Study: The study was based on data from the population-based, prospective cohort BASIC study conducted in Uppsala County, Sweden, between September 2009 and November 2018. Arginines were analyzed by Ultra-High Performance Liquid Chromatography using plasma samples taken at the onset of labor from women with spontaneous PTB (n = 34) and term birth (n = 45). We also analyzed the inflammation markers CRP, TNF-R1 and TNF-R2 and GDF-15.

Results: Women with spontaneous PTB had higher plasma levels of ADMA (p < 0.001), and L-Arginine (p = 0.03). In addition, inflammation marker, TNF-R1 (p = 0.01) was higher in spontaneous PTB compared to term birth. Further, in spontaneous PTB, no significant correlations could be observed when comparing levels of arginines with inflammation markers, except ADMA versus CRP.

Conclusions: These findings provide novel evidence for the potential involvement of arginines in the pathogenesis of spontaneous PTB and it seems that arginine levels at labor vary independently of several inflammatory markers. Further research is warranted to investigate the potential of arginines as therapeutic targets in the prevention and management of spontaneous PTB.

Hepatocellular carcinoma (HCC) is characterized by a low and variable response to chemotherapeutic treatments. One contributing factor to the overall pharmacodynamics is the activation of endoplasmic reticulum (ER) stress pathways. This is a cellular stress mechanism that becomes activated when the cell's need for protein synthesis surpasses the ER's capacity to maintain accurate protein folding, and has been implicated in creating drug-resistance in several solid tumors. Objective: To identify the role of ER-stress and lipid metabolism in mediating drug response in HCC. Methods: By using a chemically-induced mouse model for HCC, we administered the ER-stress inhibitor 4m8C and/or doxorubicin (DOX) twice weekly for three weeks post-tumor initiation. Histological analyses were performed alongside comprehensive molecular biology and lipidomics assessments of isolated liver samples. In vitro models, including HCC cells, spheroids, and patient-derived liver organoids were subjected to 4m8C and/or DOX, enabling us to assess their synergistic effects on cellular viability, lipid metabolism, and oxygen consumption rate. Results: We reveal a pivotal synergy between ER-stress modulation and drug response in HCC. The inhibition of ER-stress using 4m8C not only enhances the cytotoxic effect of DOX, but also significantly reduces cellular lipid metabolism. This intricate interplay culminates in the deprivation of energy reserves essential for the sustenance of tumor cells. Conclusions: This study elucidates the interplay between lipid metabolism and ER-stress modulation in enhancing doxorubicin efficacy in HCC. This novel approach not only deepens our understanding of the disease, but also uncovers a promising avenue for therapeutic innovation. The long-term impact of our study could open the possibility of ER-stress inhibitors and/or lipase inhibitors as adjuvant treatments for HCC-patients. (c) 2023 The Author(s). Published by Elsevier GmbH. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Continued development of laser desorption/ionization (LDI) since its inception in the 1960s has produced an explosion of soft ionization techniques, where ionization is assisted by the physical or chemical properties of a structure or matrix. While many of these techniques have primarily been used to ionize large biomolecules, including proteins, some have recently seen increasing applications to small molecules such as pharmaceuticals. Small molecules pose particular challenges for LDI techniques, including interference from the matrix or support in the low mass range. To investigate trends in the application of soft LDI techniques to small molecules, we combined text mining and computational chemistry, looking specifically at matrix substances, analyte properties, and the research domain. In addition to making visible the history of LDI techniques, the results may inform the choice of method and suggest new avenues of method development. All software and collected data are freely available on GitHub (https://github.com/ReinV/SCOPE), VOSviewer (https://www.vosviewer.com), and OSF (https://osf.io/zkmua/).