Search

Inhibitors of Kelch-like ECH-associated protein 1 (Keap1) increase the activity of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) by stalling its ubiquitination and degradation. This enhances the expression of genes encoding proteins involved in drug detoxification, redox homeostasis, and mitochondrial function. Nrf2 activation offers a potential therapeutic approach for conditions including Alzheimer's and Parkinson's diseases, vascular inflammation, and chronic obstructive airway disease. Non-electrophilic Keap1-Nrf2 protein-protein interaction (PPI) inhibitors may have improved toxicity profiles and different pharmacological properties to cysteine-reactive electrophilic inhibitors. Here, we describe and characterize a series of phenyl bis-sulfonamide PPI inhibitors that bind to Keap1 at submicromolar concentrations. Structural studies reveal that the compounds bind to Keap1 in a distinct "peptidomimetic" conformation that resembles the Keap1-Nrf2 ETGE peptide complex. This is different to other small molecule Keap1-Nrf2 PPI inhibitors, including bicyclic aryl bis-sulfonamides, offering a starting point for new design approaches to Keap1 inhibitors.

Immobilized Artificial Membrane (IAM) chromatography columns have been used to model the in vivo distribution of drug discovery compounds. Regis Technologies Inc., the manufacturer, had to replace the silica support and consequently introduced a new IAM.PC.DD2 column that shows slightly different selectivity towards acidic and basic compounds. The application of the new IAM.PC.DD2 columns has been evaluated and the in vivo distribution models have been compared with the previous batches of columns. It was found that due to the improved endcapping of the silica, some of the positively charged drug molecules showed shorter retention than previously published. Therefore, the column system suitability data have been updated. However, these differences do not significantly affect the previously published models for the volume of distribution, brain tissue binding and drug efficiency. Therefore, the published models can be used with the new IAM.PC.DD2 columns.

Amyotrophic lateral sclerosis (ALS) is caused by selective and progressive loss of spinal, bulbar and cortical motoneurons and leads to irreversible paralysis, loss of speech, inability to swallow and respiratory malfunctions with the eventual death of the affected individual in a rapid disease course. Several suggested molecular pathways are reviewed including SOD1 gene mutation, protein nitrosylation, phosphorylation and oxidative stress, excitotoxicity, glutamate transporter deprivation, mitochondrial involvement, protein aggregation and motor neuron trophic factors. The role of insulin and its receptor in the brain is described. It is very possible that in 90% of the sporadic ALS cases, the cause of the motor neuron degeneration is different or that multiple mechanisms are involved that would need drugs with multiple mechanisms or action. Several marketed drugs have been selected for clinical trials. Only two drugs have been approved by the FDA as showing positive effect in ALS: Riluzole and Edaravone. Two other drugs that have a significant benefit in ALS are Talampanel and Tamoxifen. The results for modulation of the neurotrophic factor Insulin Growth Factor-1 (IGF1) as a potential treatment are inconclusive. Several compounds are discussed that show a positive effect in the mouse model but which have failed in clinical trials. New approaches using different modalities such as peptides, proteins and stem cells are promising. Our ability to design better drugs would be enhanced by investigating the endogenous factors in neuron death, protein aggregation and oxidative stress that would improve our understanding of the potential pathways that result in neurodegeneration.

Normal phase HPLC and OPTLC methods are described for the analysis of Hevizos (5-isopropyl-2'-beta-deoxyuridine) and it's impurities. The eluent is 50% water saturated ethyl-acetate to which 0.5-1.5% methanol is added depending on the silica used. The water content is important as it practically eliminates tailing. The methods can also be used for the determination of 5-isopropyl-2'-beta-deoxyuridine and it's impurities in Hevizos ointment after a simple extraction procedure. The OPTLC method uses a CHROMPRES 10 apparatus, aluminum backed HPTLC plates and the same eluent-system as the HPLC method. The reproducibility of the HPLC method (rel. st. dev.) is 0.8%, the correlation coefficient is0.999 for the main component, while the impurities can be determined at the 0.1% level with a reproducibility of 20%, and a correlation coefficient of0.997. The reproducibility of the OPTLC method (rel. st. dev.) is 4% for the main component, while for the impurities at the 0.5% level the reproducibility is 20%.

1H-NMR and X-ray conformation studies of new muscarinergic dibenzodioxazocines have been carried out. It is suggested that EGYT-2347 (2-chloro-12-/2-piperidino-ethyl/-dibenzo [d,g] [1, 3, 6] dioxazocine hydrochloride) may exist in solution in at least two distinct conformations, unlike other tricyclic or non-tricyclic compounds having antimuscarinergic activity. One of these conformations possessing an asymmetric, twisted central hetero-ring confined between two phenyl rings is probably the energetically more stable form, while the other having a butterfly-like structure, with mirror symmetry-related phenyl rings as in phenothiazines seems to be more suitable for receptor binding. The importance of the hydrophobic pocket at the receptor site was revealed by the good correlation of the calculated and measured hydrophobic parameters to the muscarinic activity of these newly synthesized and other known muscarinergic compounds.

A fast gradient HPLC method (cycle time 15 min) has been developed to determine Human Serum Albumin (HSA) binding of discovery compounds using chemically bonded protein stationary phases. The 2- propanol concentration is increased from 0 to 25% in 3 minutes, thus allowing strongly bond compounds to elute within the 15 minutes. The HSA binding values were derived from the logarithmic values of the gradient retention times that were converted to logarithm of the equilibrium constants (logK HSA) using a calibration set of molecules. The logK HSA values for the calibration set of molecules have been derived from literature values of the % plasma protein binding. The method is fully automated and it has been used for lead optimization in more than 20 projects. The obtained HSA binding data on more than 4000 compounds were suitable to set up global and project specific quantitative structure binding relationships that helped compound design in the early drug discovery settings. The method has been validated using literature plasma protein binding data of 70 known drug molecules. It was shown that compound lipophilicity dominates the HSA binding, however compounds binding to a specific binding site show stronger HSA binding that can be expected from their lipophilicity values. The solvation equation approach has been used to characterize the non-specific lipophilic binding ability of HSA. Based on our approach we can identify compounds with specific and non-specific binding.