Identification and characterization of related substances in EVT-401 by hyphenated LC-MS techniques

Synthetic molecules as P2X7 receptor antagonists: A medicinal chemistry update focusing the therapy of inflammatory diseases

Stimulation of the P2X7 receptor by extracellular adenosine 5'-triphosphate induces a series of responses in the organism, exceptionally protein cascades related to the proinflammatory process. This has made P2X7 a target for research on inflammatory diseases such as rheumatoid arthritis. Thus, the incessant search for new prototypes that aim to antagonize the action of P2X7 has been remarkable in recent decades, a factor that has already led to numerous clinical studies in humans. In this review, we present the key molecules developed over the years with potential inhibition of P2X7 and inflammation. In addition, an update with newly developed chemical classes with promising activity and results in clinical studies for human pathologies focusing on P2X7 inhibition.

LC-HRMS and NMR studies for characterization of forced degradation impurities of ponatinib, a tyrosine kinase inhibitor, insights into in-silico degradation and toxicity profiles

The degradation profile of ponatinib was established during the present study by exposing it to various stress conditions. In-silico degradation pattern of ponatinib was outlined by using Zeneth software. Five degradation impurities were formed during the stress testing of ponatinib. High performance liquid chromatographic method was developed to separate these degradation impurities which includes ammonium acetate of pH 4.75 (A) and methanol (B) as mobile phase in gradient elution mode and Waters Reliant C18 (4.6 × 250 mm, 5 µm) column as stationary phase. Optimised flow rate, injection volume and detection wavelength of the HPLC method were 1.0 mL/min, 10 µL and 254 nm, respectively. Chemical structures of degradation impurities were proposed by high resolution mass spectrometry further, major degradation products were isolated, enriched and investigated thoroughly with the aid of nuclear magnetic resonance spectroscopy studies. The degradation impurities were identified as 4-aminophthalaldehyde (DP 1), 4-((4-methylpiperazin-1-yl)methyl)- 3-(trifluoromethyl) benzenamine (DP 2), 3-(2-(imidazo[1,2-b]pyridazin-3-yl)acetyl)- 4-methylbenzoic acid (DP 3), 3-(2-(imidazo[1,2-b]pyridazin-3-yl)ethynyl)- 4-methylbenzoic acid (DP 4) and N-oxide impurity (DP 5) which are new and were not reported in the literature till date. Additionally, toxicity and mutagenicity profiles of ponatinib and its degradation impurities were predicted in-silico by using DEREK and SARAH software. This whole study gives meaningful insights about chemical stability of ponatinib which is useful in its drug development lifecycle.

Purinergic receptors modulators: An emerging pharmacological tool for disease management

Purinergic signaling is mediated through extracellular nucleotides (adenosine 5'-triphosphate, uridine-5'-triphosphate, adenosine diphosphate, uridine-5'-diphosphate, and adenosine) that serve as signaling molecules. In the early 1990s, purines and pyrimidine receptors were cloned and characterized drawing the attention of scientists toward this aspect of cellular signaling. This signaling pathway is comprised of four subtypes of adenosine receptors (P1), eight subtypes of G-coupled protein receptors (P2YRs), and seven subtypes of ligand-gated ionotropic receptors (P2XRs). In current studies, the pathophysiology and therapeutic potentials of these receptors have been focused on. Various ligands, modulating the functions of purinergic receptors, are in current clinical practices for the treatment of various neurodegenerative disorders and cardiovascular diseases. Moreover, several purinergic receptors ligands are in advanced phases of clinical trials as a remedy for depression, epilepsy, autism, osteoporosis, atherosclerosis, myocardial infarction, diabetes, irritable bowel syndrome, and cancers. In the present study, agonists and antagonists of purinergic receptors have been summarized that may serve as pharmacological tools for drug design and development.

P2X7 Receptors in Neurodegeneration: Potential Therapeutic Applications From Basic to Clinical Approaches

Purinergic receptors play important roles in central nervous system (CNS), where the bulk of these receptors are implicated in neuroinflammatory responses and regulation of cellular function of neurons, microglial and astrocytes. Within the P2X receptor family, P2X₇ receptor is generally known for its inactivity in normal conditions and activation by moderately high concentrations (>100 μM) of extracellular adenosine 5′-triphosphate (ATP) released from injured cells as a result of brain injury or pathological conditions. Activation of P2X₇R contributes to the activation and proliferation of microglia and directly contribute to neurodegeneration by provoking microglia-mediated neuronal death, glutamate-mediated excitotoxicity, and NLRP3 inflammasome activation that results in initiation, maturity and release of the pro-inflammatory cytokines and generation of reactive oxygen and nitrogen species. These components of the inflammatory response play important roles in many neural pathologies and neurodegeneration disorders. In CNS, expression of P2X₇R on microglia, astrocytes, and oligodendrocytes are upregulated under neuroinflammatory conditions. Several in vivo studies have demonstrated beneficial effects of the P2X₇ receptor antagonists in animal model systems of neurodegenerative diseases. A number of specific and selective P2X₇ receptor antagonists have been developed, but only few of them have shown efficient brain permeability. Finding potent and selective P2X₇ receptor inhibitors which are also CNS penetrable and display acceptable pharmacokinetics (PK) has presented challenges for both academic researchers and pharmaceutical companies. In this review, we discuss the role of P2X₇ receptor function in neurodegenerative diseases, the pharmacological inhibition of the receptor, and PET radiopharmaceuticals which permit non-invasive monitoring of the P2X₇ receptor contribution to neuroinflammation associated with neurodegeneration.