1. Investigación

The development of new molecules for the treatment of leishmaniasis is, a neglected parasitic disease, is urgent as current anti-leishmanial therapeutics are hampered by drug toxicity and resistance. The pyrrolo[ 1,2-b]isoquinoline core was selected as starting point, and palladium-catalyzed Heck-initiated cascade reactions were developed for the synthesis of a series of C-10 substituted derivatives. Their in vitro leishmanicidal activity against visceral (L. donovani) and cutaneous (L. amazonensis) leishmaniasis was evaluated. The best activity was found, in general, for the 10-arylmethyl substituted pyrroloisoquinolines. In particular, 2ad (IC50 ¼ 3.30 mM, SI > 77.01) and 2bb (IC50 ¼ 3.93 mM, SI > 58.77) were approximately 10-fold more potent and selective than the drug of reference (miltefosine), against L. amazonensis on in vitro promastigote assays, while 2ae was the more active compound in the in vitro amastigote assays (IC50 ¼ 33.59 mM, SI > 8.93). Notably, almost all compounds showed low cytotoxicity, CC50 > 100 mg/mL in J774 cells, highest tested dose. In addition, we have developed the first Perturbation Theory Machine Learning (PTML) algorithm able to predict simultaneously multiple biological activity parameters (IC50, Ki, etc.) vs. any Leishmania species and target protein, with high values of specificity (>98%) and sensitivity (>90%) in both training and validation series. Therefore, this model may be useful to reduce time and assay costs (material and human resources) in the drug discovery process.

Nano-enabled lipid based drug delivery systems offer a platform to overcome challenges encountered with current failed leads in the treatment of parasitic and infectious diseases. When prepared with FDA or EMA approved excipients, they can be readily translated without the need for further toxicological studies, while they remain affordable and amenable to scale-up. Buparvaquone (BPQ), a hydroxynapthoquinone with in vitro activity in the nanomolar range, failed to clinically translate as a viable treatment for visceral leishmaniasis due to its poor oral bioavailability limited by its poor aqueous solubility (BCS Class II drug). Here we describe a self-nanoemulsifying system (SNEDDS) with high loading and thermal stability up to 6 months in tropical conditions able to enhance the solubilisation capacity of BPQ in gastrointestinal media as demonstrated by flow-through cell and dynamic in vitro lipolysis studies. BPQ SNEDDS demonstrated an enhanced oral bioavailbility compared to aqueous BPQ dispersions (probe – sonicated) resulting in an increased plasma AUC0-24 by 55% that is four fold higher than any previous reported values for BPQ formulations. BPQ SNEDDS can be adsorbed on low molecular glycol chitosan polymers forming solid dispersions that when compressed into tablets allow the complete dissolution of BPQ in gastrointestinal media. BPQ SNEDDS and BPQ solid SNEDDS demonstrated potent in vitro efficacy in the nanomolar range (<37 nM) and were able to near completely inhibit parasite replication in the spleen and 48 ± 48 and 56 ± 23% inhibition of the parasite replication in the liver respectively compared to oral miltefosine after daily administration over 10 days. The proposed platform technology can be used to elicit a range of cost-effective and orally bioavailable non-invasive formulations for a range of antiparasitic and infectious disease drugs that are needed for closing the global health innovation gap.

Leishmaniasis is a neglected tropical disease that currently affects 12 million people, and over 1 billion people are at risk of infection. Current chemotherapeutic approaches used to treat this disease are unsatisfactory, and the limitations of these drugs highlight the necessity to develop treatments with improved efficacy and safety. To inform the rational design and development of more efficient therapies, the present study reports a chemoinformatic approach using the ChEMBL database to retrieve benzimidazole as a target scaffold. Our analysis revealed that a limited number of studies had investigated the antileishmanial effects of benzimidazoles. Among this limited number, L. major was the species most commonly used to evaluate the antileishmanial effects of these compounds, whereas L. amazonensis and L. braziliensis were used least often in the reported studies. The antileishmanial activities of benzimidazole derivatives were notably variable, a fact that may depend on the substitution pattern of the scaffold. In addition, we investigated the effects of a benzimidazole derivative on promastigotes and amastigotes of L. infantum and L. amazonensis using a novel fluorometric method. Significant antileishmanial effects were observed on both species, with L. amazonensis being the most sensitive. To the best of our knowledge, this chemoinformatic analysis represents the first attempt to determine the relevance of benzimidazole scaffolds for antileishmanial drug discovery using the ChEMBL database. The present findings will provide relevant information for future structure–activity relationship studies and for the investigation of benzimidazole-derived drugs as potential treatments for leishmaniasis.