ABSTRACT
We report an automated flow chemistry platform that can efficiently perform a wide range of chemistries, including single/multi-phase and single/multi-step, with a reaction volume of just 14 µL. The breadth of compatible chemistries is successfully demonstrated and the desired products are characterized, isolated, and collected online by preparative HPLC/MS/ELSD.
Subject(s)
Chemistry, Pharmaceutical/instrumentation , Chemistry, Pharmaceutical/methods , Drug Discovery , Automation , Chromatography, High Pressure Liquid , Combinatorial Chemistry Techniques , Dynamic Light Scattering , Mass SpectrometryABSTRACT
A novel 2,6-naphthyridine was identified by high throughput screen (HTS) as a dual protein kinase C/D (PKC/PKD) inhibitor. PKD inhibition in the heart was proposed as a potential antihypertrophic mechanism with application as a heart failure therapy. As PKC was previously identified as the immediate upstream activator of PKD, PKD vs PKC selectivity was essential to understand the effect of PKD inhibition in models of cardiac hypertrophy and heart failure. The present study describes the modification of the HTS hit to a series of prototype pan-PKD inhibitors with routine 1000-fold PKD vs PKC selectivity. Example compounds inhibited PKD activity in vitro, in cells, and in vivo following oral administration. Their effects on heart morphology and function are discussed herein.
Subject(s)
Aminopyridines/chemical synthesis , Naphthyridines/chemical synthesis , Protein Kinase C/antagonists & inhibitors , Active Transport, Cell Nucleus , Administration, Oral , Aminopyridines/pharmacokinetics , Aminopyridines/pharmacology , Animals , Antihypertensive Agents/chemical synthesis , Antihypertensive Agents/chemistry , Antihypertensive Agents/pharmacology , Blood Pressure/drug effects , Cardiomegaly/drug therapy , Cardiomegaly/pathology , Cell Nucleus/metabolism , Histone Deacetylases/metabolism , Isoenzymes/antagonists & inhibitors , Male , Models, Molecular , Muscle Cells/drug effects , Muscle Cells/metabolism , Muscle Cells/pathology , Myocardium/metabolism , Myocardium/pathology , Naphthyridines/pharmacokinetics , Naphthyridines/pharmacology , Phosphorylation , Protein Binding , Rats , Rats, Inbred Dahl , Rats, Sprague-Dawley , Structure-Activity RelationshipABSTRACT
Parathyroid hormone (PTH) is an effective bone anabolic agent. However, only when administered by daily sc injections exposure of short duration is achieved, a prerequisite for an anabolic response. Instead of applying exogenous PTH, mobilization of endogenous stores of the hormone can be envisaged. The secretion of PTH stored in the parathyroid glands is mediated by a calcium sensing receptor (CaSR) a GPCR localized at the cell surface. Antagonists of CaSR (calcilytics) mimic a state of hypocalcaemia and stimulate PTH release to the bloodstream. Screening of the internal compound collection for inhibition of CaSR signaling function afforded 2a. In vitro potency could be improved >1000 fold by optimization of its chemical structure. The binding mode of our compounds was predicted based on molecular modeling and confirmed by testing with mutated receptors. While the compounds readily induced PTH release after iv application a special formulation was needed for oral activity. The required profile was achieved by using microemulsions. Excellent PK/PD correlation was found in rats and dogs. High levels of PTH were reached in plasma within minutes which reverted to baseline in about 1-2 h in both species.
