Ivermectin: Potential Repurposing of a Versatile Antiparasitic as a Novel Anticancer

Drug repositioning is a alternative strategy to discover and develop anticancer drugs based on identification of new mechanisms of actions and indications for existing compounds. Ivermectin belongs to the avermectin group of compounds, a series of 16-membered macrocyclic lactone moieties discovered in 1967 and FDA-approved for human use since 1987. Ivermectin has since been used by millions of people worldwide, and have demonstrated a wide margin of clinical safety. Here we summarize the in vitro and in vivo evidence demonstrating ivermectin\'s potential as a multitargeting anticancer drug that exerts antitumor effects against different tumor types. Notably, the in vitro and in vivo antitumor activities of ivermectin are achieved at concentrations that can be clinically achieved based on human pharmacokinetic studies done in the clinical studies. Moreover, repurposed ivermectin safety has been well established recently in clinical studies against COVID-19. Consequently, we believe that ivermectin is an excellent potential candidate drug that can be repurposed for cancer and deserves rigorous evaluation against a variety of cancers in well-designed clinical trials.

Antimicrobial Activity of Non-steroidal Anti-inflammatory Drugs on Biofilm: Current Evidence and Potential for Drug Repurposing

It has been demonstrated that some non-steroidal anti-inflammatory drugs (NSAIDs), like acetylsalicylic acid, diclofenac, and ibuprofen, have anti-biofilm activity in concentrations found in human pharmacokinetic studies, which could fuel an interest in repurposing these well tolerated drugs as adjunctive therapies for biofilm-related infections. Here we sought to review the currently available data on the anti-biofilm activity of NSAIDs and its relevance in a clinical context. We performed a systematic literature review to identify the most commonly tested NSAIDs drugs in the last 5 years, the bacterial species that have demonstrated to be responsive to their actions, and the emergence of resistance to these molecules. We found that most studies investigating NSAIDs’ activity against biofilms were in vitro, and frequently tested non-clinical bacterial isolates, which may not adequately represent the bacterial populations that cause clinically-relevant biofilm-related infections. Furthermore, studies concerning NSAIDs and antibiotic resistance are scarce, with divergent outcomes. Although the potential to use NSAIDs to control biofilm-related infections seems to be an exciting avenue, there is a paucity of studies that tested these drugs using appropriate in vivo models of biofilm infections or in controlled human clinical trials to support their repurposing as anti-biofilm agents.

Prediction of Human Pharmacokinetic Profiles of the Anti-tuberculosis Drug Delamanid from Nonclinical Data: Potential Therapeutic Value Against Extrapulmonary Tuberculosis

Delamanid has been studied extensively and approved for the treatment of pulmonary multidrug-resistant tuberculosis; however, its potential in the treatment of extrapulmonary tuberculosis remains unknown. We previously reported that in rats, delamanid was broadly distributed to various tissues in addition to the lungs. In this study, we simulated human plasma concentration–time courses (pharmacokinetic profile) of delamanid, which has a unique property of metabolism by albumin, using two different approaches (steady-state concentration of plasma-mean residence time [C ss -MRT] and physiologically based pharmacokinetic [PBPK] modeling). In C ss -MRT, allometric scaling predicted the distribution volume at steady state based on data from mice, rats, and dogs. Total clearance was predicted by in vitro – in vivo extrapolation using a scaled albumin amount. A simulated human pharmacokinetic profile using a combination of human predicted C ss and MRT was almost identical to the observed profile after single oral administration, which suggests that the pharmacokinetic profile of delamanid could be predicted by allometric scaling from these animals and metabolic capacity in vitro . The PBPK model was constructed on the assumption that delamanid was metabolized by albumin in circulating plasma and tissues; to which, the simulated pharmacokinetic profile was consistent. Moreover, the PBPK modeling approach demonstrated that the simulated concentrations of delamanid at steady state in the lung, brain, liver, and heart were higher than the in vivo effective concentration for Mycobacterium tuberculosis . These results indicate that delamanid may achieve similar concentrations in various organs to that of the lung and may have the potential to treat extrapulmonary tuberculosis.

Critical Analysis of Human Exposure to Bisphenol a and its Novel Implications on Renal, Cardiovascular and Hypertensive Diseases

Bisphenol A (BPA), an endocrine disruptor involved in synthesizing numerous types of plastics, is detected in almost the entire population’s urine. The present work aims to estimate daily exposure to BPA by systematically reviewing all articles with original data related to urinary BPA concentration. This approach is based on human pharmacokinetic models, which have shown that 100% of BPA (free and metabolized form) is eliminated only in a few hours through urine. Several extensive population studies and experimental data have recently proven a significant association between urinary excretion of BPA and albuminuria, associated with renal damage. Our team’s previous work has shown that low-dose BPA can promote a cytotoxic effect on renal mouse podocytes. Moreover, BPA administration in mice promotes kidney damage and hypertension. Furthermore, preliminary studies in human renal cells in culture (podocytes) strongly suggest that BPA might also promote kidney damage. Overall, the present review analyzed BPA exposure data from mammalian cell studies, experimental animal models, and several human populations. Studying principal cohorts calculated the exposures to BPA globally, showing a high BPA exposure suggesting the need to decrease BPA exposure more effectively, emphasizing groups with higher sensitivity as kidney disease patients.

New Insights into the Metabolism of the Flavanones Eriocitrin and Hesperidin: A Comparative Human Pharmacokinetic Study

The intake of hesperidin-rich sources, mostly found in orange juice, can decrease cardiometabolic risk, potentially linked to the gut microbial phase-II hesperetin derivatives. However, the low hesperidin solubility hampers its bioavailability and microbial metabolism, yielding a high inter-individual variability (high vs. low-producers) that prevents consistent health-related evidence. Contrarily, the human metabolism of (lemon) eriocitrin is hardly known. We hypothesize that the higher solubility of (lemon) eriocitrin vs. (orange) hesperidin might yield more bioavailable metabolites than hesperidin. A randomized-crossover human pharmacokinetic study (n = 16) compared the bioavailability and metabolism of flavanones from lemon and orange extracts and postprandial changes in oxidative, inflammatory, and metabolic markers after a high-fat-high-sugars meal. A total of 17 phase-II flavanone-derived metabolites were identified. No significant biomarker changes were observed. Plasma and urinary concentrations of all metabolites, including hesperetin metabolites, were higher after lemon extract intake. Total plasma metabolites showed significantly mean lower Tmax (6.0 ± 0.4 vs. 8.0 ± 0.5 h) and higher Cmax and AUC values after lemon extract intake. We provide new insights on hesperetin-eriodictyol interconversion and naringenin formation from hesperidin in humans. Our results suggest that regular consumption of a soluble and eco-friendly eriocitrin-rich lemon extract could provide a circulating concentration metabolites threshold to exert health benefits, even in the so-called low-producers.

Shared IVIVR for Five Commercial Enabling Formulations Using the BiPHa+ Biphasic Dissolution Assay

The present study intended to confirm the in vivo relevance of the BiPHa+ biphasic dissolution assay using a single set of assay parameters. Herein, we evaluated five commercial drug products formulated by various enabling formulation principles under fasted conditions using the BiPHa+ assay. The in vitro partitioning profiles in the organic phase were compared with human pharmacokinetic data obtained from literature. In the first part, a meaningful in vitro dose of the formulations was assessed by determining the maximum drug concentration in the artificial absorption sink during dissolution (organic 1-decanol layer, Cdec,max). Then, the maximum concentration of the partitioned drug in the organic layer was correlated with the in vivo fraction absorbed, which was derived from published human pharmacokinetic data. Fraction absorbed represents the percentage, which is absorbed from the intestine without considering first pass. It was found that the maximum drug concentration in the organic phase obtained from an in vitro dose of ten milligrams, which is equivalent to 15–25 µmol of the respective drug, led to the highest congruency with the fraction absorbed in vivo. In the second part, the in vivo relevance of the BiPHa+ dissolution data was verified by establishing a shared in vitro/in vivo relationship including all formulations. Based on the in vitro kinetics of the BiPHa+ experiments human in vivo plasma profiles were predicted using convolutional modelling approach. Subsequently, the calculated pharmacokinetic profiles were compared with in vivo performance of the studied drug products to assess the predictive power of the BiPHa+ assay. The BiPHa+ assay demonstrated biorelevance for the investigated in vitro partitioning profiles using a single set of assay parameters, which was verified based on human pharmacokinetic data of the five drug products.