Development and validation of a novel method for simultaneous quantification of enzalutamide, darolutamide and their active metabolites in mice dried blood spots using LC-MS/MS: Application to pharmacokinetic study in mice

A simple, sensitive and rapid assay method has been developed and validated for the estimation of enzalutamide, N-desmethylenzalutamide (active metabolite of enzalutamide), darolutamide and ORM-15341 (active metabolite of darolutamide) on mice dried blood spots (DBS) using liquid chromatography coupled to tandem mass spectrometry with electro spray ionization in the positive-ion mode. The method utilizes liquid extraction of enzalutamide, N-desmethylenzalutamide, darolutamide and ORM-15341 from 3 mm punched disks from DBS cards (spiked or study samples). The extracted sample was chromatographed using an isocratic mobile phase (0.2 % formic acid : acetonitrile; 30:70, v/v) on an Atlantis dC18 column. The total run time was 2.5 min. The MS/MS ion transitions monitored were m/z 465 → m/z 209, m/z 451 →  m/z 195, m/z 399 → m/z 178, m/z 397 →  m/z 194 and m/z 481 → m/z 453 for enzalutamide, N-desmethyl­enzalutamide, darolutamide, ORM-15341 and the IS (apalutamide-d3), respectively. Method validation was performed as per regulatory guideline. The assay had a good linearity over the range of 0.93-2000 ng/mL. The intra- and inter-batch accuracy and precision (%RE & RSD) across quality controls met the acceptance criteria for all the analytes. Stability studies showed that all the analytes were stable on DBS cards for one month. This novel method has been applied to analyze the DBS samples of enzalutamide, N-desmethylenzalutamide, darolutamide and ORM-15341 obtained from a pharmacokinetic study in mice

Preclinical assessment of ulixertinib, a novel ERK1/2 inhibitor

Ulixertinib (BVD-523) is a novel and selective reversible inhibitor of ERK1/ERK2. In xenograft studies it inhibited tumor growth in BRAF-mutant melanoma and colorectal xenografts as well as KRAS-mutant colorectal and pancreatic models. Ulixertinib is currently in Phase I clinical development for the treatment of advance solid tumors. The objective of the study is to assess the metabolic stability (in various pre-clinical and human liver microsomes/hepatocytes), permeability, protein binding, CYP inhibition, CYP induction and CYP phenotyping of ulixertinib. We have also studied the oral and intravenous pharmacokinetics of ulixertinib in mice, rats and dogs. Ulixertinib was found to be moderately to highly stable in various liver microsomes/hepatocytes tested. It is a medium permeable (2.67 x 10-6 cm /sec) drug and a substrate for efflux (efflux ratio: 3.02) in Caco-2 model. Ulixertinib was highly bound to plasma proteins. CYPs involved in its limited metabolism and it is CYP inhibition IC50 ranged between 10-20 μM. Post oral administration ulixertinib exhibited early Tmax (0.50-0.75 h) in mice and rats indicating absorption was rapid, however in dogs Tmax attained at 2 h. The half-life (t½) of ulixertinib by intravenous and oral routes ranged between 1.0-2.5 h across the species. Clearance and volume of distribution by intravenous route for ulixertinib were found to be 6.24 mL/min/kg and 0.56 L/kg; 1.67 mL/min/kg and 0.36 L/kg and 15.5 mL/min/kg and 1.61 L/kg in mice, rats and dogs, respectively. Absolute oral bioavailability in mice and rats was > 92 %, however in dogs it was 34 %

Preclinical assessment of ulixertinib, a novel ERK1/2 inhibitor

Ulixertinib (BVD-523) is a novel and selective reversible inhibitor of ERK1/ERK2. In xenograft studies it inhibited tumor growth in BRAF-mutant melanoma and colorectal xenografts as well as KRAS-mutant colorectal and pancreatic models. Ulixertinib is currently in Phase I clinical development for the treatment of advance solid tumors. The objective of the study is to assess the metabolic stability (in various pre-clinical and human liver microsomes/hepatocytes), permeability, protein binding, CYP inhibition, CYP induction and CYP phenotyping of ulixertinib. We have also studied the oral and intravenous pharmacokinetics of ulixertinib in mice, rats and dogs. Ulixertinib was found to be moderately to highly stable in various liver microsomes/hepatocytes tested. It is a medium permeable (2.67 x 10-6 cm /sec) drug and a substrate for efflux (efflux ratio: 3.02) in Caco-2 model. Ulixertinib was highly bound to plasma proteins. CYPs involved in its limited metabolism and it is CYP inhibition IC50 ranged between 10-20 µM. Post oral administration ulixertinib exhibited early Tmax (0.50-0.75 h) in mice and rats indicating absorption was rapid, however in dogs Tmax attained at 2 h. The half-life (t½) of ulixertinib by intravenous and oral routes ranged between 1.0-2.5 h across the species. Clearance and volume of distribution by intravenous route for ulixertinib were found to be 6.24 mL/min/kg and 0.56 L/kg; 1.67 mL/min/kg and 0.36 L/kg and 15.5 mL/min/kg and 1.61 L/kg in mice, rats and dogs, respectively. Absolute oral bioavailability in mice and rats was > 92 %, however in dogs it was 34 %

HIV-1 Tat Protein Promotes Neuroendocrine Dysfunction Concurrent with the Potentiation of Oxycodone’s Psychomotor Effects in Female Mice

Human immunodeficiency virus (HIV) is associated with neuroendocrine dysfunction which may contribute to co-morbid stress-sensitive disorders. The hypothalamic-pituitary-adrenal (HPA) or -gonadal (HPG) axes are perturbed in up to 50% of HIV patients. The mechanisms are not known, but we have found the HIV-1 trans-activator of transcription (Tat) protein to recapitulate the clinical phenotype in male mice. We hypothesized that HPA and/or HPG dysregulation contributes to Tat-mediated interactions with oxycodone, an opioid often prescribed to HIV patients, in females. Female mice that conditionally-expressed the Tat1–86 protein [Tat(+) mice] or their counterparts that did not [Tat(−) control mice] were exposed to forced swim stress (or not) and behaviorally-assessed for motor and anxiety-like behavior. Some mice had glucocorticoid receptors (GR) or corticotropin-releasing factor receptors (CRF-R) pharmacologically inhibited. Some mice were ovariectomized (OVX). As seen previously in males, Tat elevated basal corticosterone levels and potentiated oxycodone’s psychomotor activity in females. Unlike males, females did not demonstrate adrenal insufficiency and oxycodone potentiation was not regulated by GRs or CRF-Rs. Rather OVX attenuated Tat/oxycodone interactions. Either Tat or oxycodone increased anxiety-like behavior and their combination increased hypothalamic allopregnanolone. OVX increased basal hypothalamic allopregnanolone and obviated Tat or oxycodone-mediated fluctuations. Together, these data provide further evidence for Tat-mediated dysregulation of the HPA axis and reveal the importance of HPG axis regulation in females. HPA/HPG disruption may contribute vulnerability to affective and substance use disorders

Identification of an Orally Bioavailable, Brain-Penetrant Compound with Selectivity for the Cannabinoid Type 2 Receptor

Modulation of the endocannabinoid system (ECS) is of great interest for its therapeutic relevance in several pathophysiological processes. The CB2 subtype is largely localized to immune effectors, including microglia within the central nervous system, where it promotes anti-inflammation. Recently, a rational drug design toward precise modulation of the CB2 active site revealed the novelty of Pyrrolo[2,1-c][1,4]benzodiazepines tricyclic chemotype with a high conformational similarity in comparison to the existing leads. These compounds are structurally unique, confirming their chemotype novelty. In our continuing search for new chemotypes as selective CB2 regulatory molecules, following SAR approaches, a total of 17 selected (S,E)-11-[2-(arylmethylene)hydrazono]-PBD analogs were synthesized and tested for their ability to bind to the CB1 and CB2 receptor orthosteric sites. A competitive [H]CP-55,940 binding screen revealed five compounds that exhibited \u3e60% displacement at 10 μM concentration. Further concentration-response analysis revealed two compounds, and , as potent and selective CB2 ligands with sub-micromolar activities ( = 146 nM and 137 nM, respectively). In order to support the potential efficacy and safety of the analogs, the oral and intravenous pharmacokinetic properties of compound were sought. Compound was orally bioavailable, reaching maximum brain concentrations of 602 ± 162 ng/g (p.o.) with an elimination half-life of 22.9 ± 3.73 h. Whether administered via the oral or intravenous route, the elimination half-lives ranged between 9.3 and 16.7 h in the liver and kidneys. These compounds represent novel chemotypes, which can be further optimized for improved affinity and selectivity toward the CB2 receptor