Fentanyl and other New Psychoactive Synthetic Opioids. Challenges to Prevention and Treatment

ABSTRACT Synthetic opioids have played a significant role in the current opioid crisis in the United States (U.S.) and Canada and are a matter of concern worldwide. New psychoactive opioids (NPOs) are classified in the internationally recognized new psychoactive substances (NPSs) category. This group comprises compounds that may have been synthesized decades ago but appeared only recently in the illicit drug market. Such is the case of fentanyl, fentanyl analogs, and non-fentanyl opioids. Most NPOs have effects similar to morphine, including euphoria and analgesia, and can produce fatal respiratory depression. Here, we present an overview of the systemic and molecular effects of main NPOs, their classification, and their pharmacological properties. We first review the fentanyl group of NPOs, including the four compounds of clinical use (fentanyl, alfentanil, sufentanil, and remifentanil) and the veterinary drug carfentanil. We also provide essential information on non-medical fentanyl analogs and other synthetic opioids such as brorphine, etonitazene, and MT-45, used as adulterants in commonly misused drugs. This paper also summarizes the scarce literature on the use of NPOs in Mexico. It concludes with a brief review of the challenges to prevention and treatment posed by NPOs and some recommendations to face them.

Benzimidazole and its derivatives as cancer therapeutics: The potential role from traditional to precision medicine

Cancer is the second leading cause of mortality globally which remains a continuing threat to human health today. Drug insensitivity and resistance are critical hurdles in cancer treatment; therefore, the development of new entities targeting malignant cells is considered a high priority. Targeted therapy is the cornerstone of precision medicine. The synthesis of benzimidazole has garnered the attention of medicinal chemists and biologists due to its remarkable medicinal and pharmacological properties. Benzimidazole has a heterocyclic pharmacophore, which is an essential scaffold in drug and pharmaceutical development. Multiple studies have demonstrated the bioactivities of benzimidazole and its derivatives as potential anticancer therapeutics, either through targeting specific molecules or non-gene-specific strategies. This review provides an update on the mechanism of actions of various benzimidazole derivatives and the structure‒activity relationship from conventional anticancer to precision healthcare and from bench to clinics.

New benzimidazole derivatives as inhibitors of Pteridine reductase 1: Design, molecular docking study and ADMET prediction

Pteridine reductase 1 (PTR1) is a unique enzyme required for survival of Leishmania species, a causative organism forthe disease leishmaniasis. We herein report the design, docking, and Absorption, Distribution, Metabolism, Excretion,Toxicity (ADMET) prediction studies of 2-substituted-5-[(6-substituted-1H-benzimidazol-2yl)methyl]azole derivatives(B1–B14) as PTR1 inhibitors. Molecular docking studies showed good binding interaction of the compounds withthe active site of pteridine reductase from Leishmania Major, with compounds B5 and B12 showing docking scoresof −61.5232 and −62.5897, respectively, which were comparable with the original ligand, dihydrobiopterin. Largesubstituents on the azole ring, as well as substitutions on sixth position of the benzimidazole ring, were found to befavorable for interaction with PTR1 active site. Physicochemical properties, bioactivity prediction, and toxicity profilesof the compounds were studied using the Molinspiration and admetSAR web servers. All compounds followed Lipinski’srule of five and can be considered as good oral candidates. Bioactivity prediction indicated that the compounds wereenzyme inhibitor, thus the rationale for designing PTR1 inhibitors was met. Most of the compounds were predicted tohave good ADMET properties in terms of Gastrointestinal (GI) absorption, absence of P-glycoprotein interaction, andLD50 values in rats. The designed molecules can be further explored for their antileishmanial activity

Discovery of highly selective and orally available benzimidazole-based phosphodiesterase 10 inhibitors with improved solubility and pharmacokinetic properties for treatment of pulmonary arterial hypertension

Optimization efforts were devoted to discover novel PDE10A inhibitors in order to improve solubility and pharmacokinetics properties for a long-term therapy against pulmonary arterial hypertension (PAH) starting from the previously synthesized inhibitor