Carolina L. Bellera

Prediction of drug intestinal absorption by new linear and non-linear QSPR

In order to minimize the high attrition rate that usually characterizes drug research and development projects, current medicinal chemists aim to characterize both pharmacological and ADME profiles at the beginning of drug R&D initiatives. Thus, the development of ADME High-Throughput Screening in vitro and in silico ADME models has become an important growing research area. Here we present new linear and non-linear predictive QSPR models to predict the human intestinal absorption rate, which are derived from a medium sized, balanced and diverse training set of organic compounds. The structure-property relationships so obtained involve only 4 molecular descriptors, and display an excellent ratio of number of cases to number of descriptors. Their adjustment of the training set data together with the performance achieved during the internal and external validation procedures are comparable to previously reported modeling efforts.

An Integrated Drug Development Approach Applying Topological Descriptors

We describe the opportunities posed by computer-assisted drug design in the light of two aspects of the current drug discovery scenario: the decline of innovation due to high attrition rates at clinical stage of development and the combinatorial explosion emerging from exponential growth of feasible small molecules and genome and proteome exploration. We present an overview of recent reports from our group in the field of rational drug development, by using topological descriptors (either alone, or in combination with different 3D approaches) and a diversity of modeling techniques such as Linear Discriminant Analysis and the Replacement Method. Modeling efforts aimed at the integrated prediction of several significant molecular properties in the field of drug discovery, such as pharmacological activity, aqueous solubility, human intestinal permeability and affinity to P-glycoprotein (ABCB1, MDR1) are reviewed. The suitability of conformation-independent descriptors to explore large chemical repositories is highlighted, as well as the opportunities posed by in silico guided drug repurposing.

Synthesis of 2-Hydrazolyl-4-Thiazolidinones Based on Multicomponent Reactions and Biological Evaluation Against Trypanosoma Cruzi

A series of 18 novel 2‐hydrazolyl‐4‐thiazolidinones‐5‐carboxylic acids, amides and 5,6‐α,β‐unsaturated esters were synthesized, and their in vitro activity on cruzipain and T. cruzi epimastigotes was determined. Some agents show activity at 37 μm concentration in the enzyme assay. Computational tools and docking were used to correlate the biological response with the physicochemical parameters of the compounds and their cruzipain inhibitory effects.

Computer-guided drug repurposing: Identification of trypanocidal activity of clofazimine, benidipine and saquinavir

In spite of remarkable advances in the knowledge on Trypanosoma cruzi biology, no medications to treat Chagas disease have been approved in the last 40 years and almost 8 million people remain infected. Since the public sector and non-profit organizations play a significant role in the research efforts on Chagas disease, it is important to implement research strategies that promote translation of basic research into the clinical practice. Recent international public-private initiatives address the potential of drug repositioning (i.e. finding second or further medical uses for known-medications) which can substantially improve the success at clinical trials and the innovation in the pharmaceutical field. In this work, we present the computer-aided identification of approved drugs clofazimine, benidipine and saquinavir as potential trypanocidal compounds and test their effects at biochemical as much as cellular level on different parasite stages. According to the obtained results, we discuss biopharmaceutical, toxicological and physiopathological criteria applied to decide to move clofazimine and benidipine into preclinical phase, in an acute model of infection. The article illustrates the potential of computer-guided drug repositioning to integrate and optimize drug discovery and preclinical development; it also proposes rational rules to select which among repositioned candidates should advance to investigational drug status and offers a new insight on clofazimine and benidipine as candidate treatments for Chagas disease. One Sentence Summary: We present the computer-guided drug repositioning of three approved drugs as potential new treatments for Chagas disease, integrating computer-aided drug screening and biochemical, cellular and preclinical tests.

Application of Computer-Aided Drug Repurposing in the Search of New Cruzipain Inhibitors: Discovery of Amiodarone and Bromocriptine Inhibitory Effects

Cruzipain (Cz) is the major cystein protease of the protozoan Trypanosoma cruzi , etiological agent of Chagas disease. From a 163 compound data set, a 2D-classifier capable of identifying Cz inhibitors was obtained and applied in a virtual screening campaign on the DrugBank database, which compiles FDA-approved and investigational drugs. Fifty-four approved drugs were selected as candidates, four of which were acquired and tested on Cz and T. cruzi epimastigotes. Among them, the antiparkinsonian and antidiabetic drug bromocriptine and the antiarrhythmic amiodarone showed dose-dependent inhibition of Cz and antiproliferative activity on the parasite.

High-throughput Drug Repositioning for the Discovery of New Treatments for Chagas Disease

Despite affecting around 8 million people worldwide and representing an economic burden above

Identification of Levothyroxine Antichagasic Activity through Computer-Aided Drug Repurposing

7 billion/ year, currently approved medications to treat Chagas disease are still limited to two drugs, nifurtimox and benznidazole, which were developed more than 40 years ago and present important efficacy and safety limitations. Drug repositioning (i.e. finding second or further therapeutic indications for known drugs) has raised considerable interest within the international drug development community. There are many explanations to the current interest on drug repositioning including the possibility to partially circumvent clinical trials and the consequent saving in time and resources. It has been suggested as a particular attractive approach for the development of novel therapeutics for neglected diseases, which are usually driven by public or non-profit organizations. Here we review current computer-guided approaches to drug repositioning and reports on drug repositioning stories oriented to Chagas disease, with a focus on computer-guided drug repositioning campaigns.

Neglected Tropical Protozoan Diseases: Drug Repositioning as a Rational Option.

Cruzipain (Cz) is the major cysteine protease of the protozoan Trypanosoma cruzi, etiological agent of Chagas disease. A conformation-independent classifier capable of identifying Cz inhibitors was derived from a 163-compound dataset and later applied in a virtual screening campaign on the DrugBank database, which compiles FDA-approved and investigational drugs. 54 approved drugs were selected as candidates, 3 of which were acquired and tested on Cz and T. cruzi epimastigotes proliferation. Among them, levothyroxine, traditionally used in hormone replacement therapy in patients with hypothyroidism, showed dose-dependent inhibition of Cz and antiproliferative activity on the parasite.

Recent Advances on Nanotechnology Applications to Cancer Drug Therapy

Neglected tropical diseases represent a major sanitary problem and a huge economic burden to endemic countries, and are currently expanding to non-endemic countries owing to migration currents. Though long abandoned in the past, recent research on novel therapeutics has already started to show results. Drug repositioning is one of the prominent, more successful strategies to approach the development of new treatments for these diseases. Here we present an overview on the limitations of the current available medications to treat African trypanosomiasis, Chagas disease and Leishmaniasis, along with a review on drug candidates presently undergoing clinical trials and drug candidates identified through drug repositioning initiatives.

The application of molecular topology for ulcerative colitis drug discovery

One of the greatest challenges in cancer drug therapy is to maximize the effectiveness of the active ingredient while reducing its systemic adverse effects. Conventional (non-targeted) systemic drug therapy is characterized by unspecific distribution of the anticancer drugs: both healthy and affected tissues are thus exposed to the chemotherapeutic agent, giving raise to off-target side-effects. Besides, a number of widely-used chemoterapeutic agents present unfavorable physicochemical properties, such as low solubility or low stability issues, limiting their available routes of administration and therapeutic applications. Nano-delivery systems seem as promising solutions to these issues. They can be used for targeted-drug release, diagnostic imaging and therapy monitoring. Nanosystems allow the formulation of drug delivery systems with tailored properties ( e.g. solubility, biodegradability, release kinetics and distribution) that provide means to improve cancer patients’ quality of life by lowering the administered dose and, incidentally, the cost of clinical treatments. This article overviews the main features of different nanovehicles (linear and non-linear polymeric nanosystems, lipid-based systems, inorganic nanoparticles) and presents a selection of reports on applications of such systems to cancer therapy published between 2010 and 2013.