Insilico design of an allosteric modulator targeting the protein-protein interaction site of 3 Phosphoinositide dependent Kinase-1: design, synthesis and biological activity.

The signalling pathways in human cells mostly rely on protein-protein interactions (PPI) for their function. Such a PPI site in 3 Phosphoinositide dependent Kinase-1 (PDK1) is targeted to design the small molecule modulators. Based on the hotspot residues in its PPI site, a pharmacophore with seven different features was developed and screened against 2.9 million lead like compounds in Zinc database. A phthalazine derivative was identified as a potent allosteric inhibitor through virtual screening, molecular docking and 100 ns dynamics simulations. The modified hit possessed hydrogen bonds with Lys115, Arg131, Thr148, Glu150 as well as pi-pi stacking interactions with Phe157 which are the key residues in the PIF pocket of PDK1. Comparison between the free energy profiles by metadynamics simulation with the presence and absence of the modified ligand (MH) in the binding pocket indicates that the binding of MH enhances the hinge motion making PDK1 to adopt open conformation also and stabilizes the fluctuation of the end-to-end distance in αB helix of PDK1. The modified hit compound was synthesized, characterized and found to be cytotoxic to cancerous cells that are rich in PDK1 expression. These results propose that MH can serve as a new scaffold template for the design of novel drugs targeting PDK1 as well as promising allosteric regulator of PDK1 targeting its protein-protein interface. Supplementary Information: The online version contains supplementary material available at 10.1007/s40203-023-00160-6.

Scalable Asymmetric Syntheses of Foslevodopa and Foscarbidopa Drug Substances for the Treatment of Parkinson's Disease.

Foslevodopa (FLD, levodopa 4'-monophosphate, 3) and foscarbidopa (FCD, carbidopa 4'-monophosphate, 4) were identified as water-soluble prodrugs of levodopa (LD, 1) and carbidopa (CD, 2), respectively, which are useful for the treatment of Parkinson's disease. Herein, we describe asymmetric syntheses of FLD (3) and FCD (4) drug substances and their manufacture at pilot scale. The synthesis of FLD (3) employs a Horner-Wadsworth-Emmons olefination reaction followed by enantioselective hydrogenation of the double bond as key steps to introduce the α-amino acid moiety with the desired stereochemistry. The synthesis of FCD (4) features a Mizoroki-Heck reaction followed by enantioselective hydrazination to install the quaternary chiral center bearing a hydrazine moiety.

Safety Assessment of Ubiquinol Acetate: Subchronic Toxicity and Genotoxicity Studies.

Coenzyme Q10 (CoQ10) is a lipid soluble, endogenous antioxidant present at highest levels in the heart followed by the kidney and liver. The reduced CoQ10 ubiquinol is well known for its chemical instability and low bioavailability. The present study was designed to synthesize ubiquinol acetate, which is more stable and biologically active, and further evaluate its safety and genotoxic potential. Synthesized ubiquinol acetate showed better stability than that of ubiquinol at the end of 3 months. In vitro genotoxicity studies (AMES test, in vitro micronucleus and chromosomal aberration) showed ubiquinol acetate as nongenotoxic with no clastogenic or aneugenic effects at high dose of 5000 and 62.5 µg/mL, respectively. In subchronic toxicity study, ubiquinol acetate was administered orally to Sprague Dawley rats at 150, 300, and 600 mg/kg/day for 90 days. No treatment related adverse effects were observed in males at 600 mg/kg/day; however, females showed treatment related increase in AST and ALT with small focal irregular white-yellow spots in liver on gross necropsy examination. Histopathological evaluation revealed hepatocellular necrosis in high dose females which was considered as adverse. Based on the results, the No-Observed-Adverse-Effect Level (NOAEL) of ubiquinol acetate in males and females was determined as 600 and 300 mg/kg/day, respectively.