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Approximately 6-7 million people around the world are estimated to be infected with Trypanosoma cruzi, the causative agent of Chagas disease. The current treatments are inadequate and therefore new medical interventions are urgently needed. In this paper we describe the identification of a series of disubstituted piperazines which shows good potency against the target parasite but is hampered by poor metabolic stability. We outline the strategies used to mitigate this issue such as lowering logD, bioisosteric replacements of the metabolically labile piperazine ring and use of plate-based arrays for quick diversity scoping. We discuss the success of these strategies within the context of this series and highlight the challenges faced in phenotypic programs when attempting to improve the pharmacokinetic profile of compounds whilst maintaining potency against the desired target.

Phenotypic screening of a 900 compound library of antitubercular nitroimidazole derivatives related to pretomanid against the protozoan parasite Trypanosoma cruzi (the causative agent for Chagas disease) identified several structurally diverse hits with an unknown mode of action. Following initial profiling, a first proof-of-concept in vivo study was undertaken, in which once daily oral dosing of a 7-substituted 2-nitroimidazooxazine analogue suppressed blood parasitemia to low or undetectable levels, although sterile cure was not achieved. Limited hit expansion studies alongside counter-screening of new compounds targeted at visceral leishmaniasis laid the foundation for a more in-depth assessment of the best leads, focusing on both drug-like attributes (solubility, metabolic stability and safety) and maximal killing of the parasite in a shorter timeframe. Comparative appraisal of one preferred lead (58) in a chronic infection mouse model, monitored by highly sensitive bioluminescence imaging, provided the first definitive evidence of (partial) curative efficacy with this promising nitroimidazooxazine class.

Chagas’ disease, caused by the protozoan parasite Trypanosoma cruzi, affects 8–10 million people across the Latin American population and is responsible for around 12,500 deaths per annum. The current frontline treatments, benznidazole and nifurtimox, are associated with side effects and lack efficacy in the chronic stage of the disease, leading to an urgent need for new treatments. A high throughput screening campaign against the physiologically relevant intracellular form of the parasite identified a series of 2,4-diamino-6-methylpyrimidines. Demonstrating the series did not work through the anti-target TcCYP51, and was generally cytocidal, confirmed its suitability for further development. This study reports the optimisation of selectivity and metabolic stability of the series and identification of a suitable lead for further optimisation.

Twenty eight new N2,N4-diphenylpyrimidine-2,4-diamines have been prepared in order to expand our understanding of the anti-malarial SAR of the scaffold. The aim of the study was to make structural modifications to improve the overall potency, selectivity and solubility of the series by varying the anilino groups attached to the 2- and 4-position. We evaluated the activity of the compounds against Plasmodium falciparum (Pf) 3D7, cytotoxicity against HepG2, % inhibition at a panel of 10 human kinases, solubility, permeability and lipophilicity, and human and rat in vitro clearance. 11 was identified as a potent anti-malarial with an IC50 of 0.66 µM at the 3D7 strain and a selectivity (SI) of ~ 40 in terms of cytotoxicity against the HepG2 cell line. It also displayed low experimental logD7.4 (2.27), reasonable solubility (124 µg/ml), good metabolic stability, but low permeability. A proteo-chemometric workflow was employed to identify putative Pf targets of the most promising compounds. Ligand-based similarity searching of the ChEMBL database led to the identification of most probable human targets. These were then used as input for sequence-based searching of the Pf proteome. Homology modelling and molecular docking were used to evaluate whether compounds could indeed bind to these targets with valid binding modes. In vitro biological testing against close human analogs of these targets was subsequently undertaken. This allowed us to identify potential Pf targets and human anti-targets that could be exploited in future development.

Wildlife patients often present as emergencies. For veterinarians who do not typically treat wildlife, it is important to be able to stabilize and determine the underlying cause of the animal's signs. This article discusses initial assessment, stabilization, and treatment of common emergency presentations in wild birds, reptiles, and mammals.

Proponents tout plain English as a solution for improving communication of complex information to users in various areas of business, medicine, and law. The SEC’s mandate to public companies to use Plain English in their Item 1a risk factor disclosures to make them more readable is one example. Using 365 responses from an experimental survey of nonprofessional US investors, we find that readability significantly influences investors’ perceptions of probability and size of loss, economic worry, and overall risk. Further, these effects interact with type of risk factor. Readability does not appear to influence investment decisions or perception of management credibility. Finally, we find that investors report that they do not use item 1a risk factors in their investment analyses in practice. Results suggest that this area needs further research before future mandates for plain English and risk factor disclosures are enacted.