Bioanalytical method development and pharmacokinetics of MCI-92, a sigma-1 receptor ligand

UPLC-MS/MS method for the quantification of MCI-77, a novel sigma-1 receptor ligand, and its application to pharmacokinetic studies

Sigma-1 receptors are involved in pain modulation, particularly in cases of nerve injury and neuropathic pain. High-affinity ligands with improved pharmacokinetic profiles are needed to further investigate the properties of these receptors and their potential as a therapeutic target. The novel compound MCI-77 is one such selective sigma-1 receptor ligand, and the purpose of this study was to characterize its preclinical pharmacokinetic parameters. An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to quantify MCI-77 in mouse plasma and brain homogenate. The method was validated for sensitivity, selectivity, linearity, accuracy, precision, stability, and dilution integrity. The method has a linearity range of 2-200 ng/mL, a short run-time of 3.2 min, and requires a low sample volume of 25 µL. A simple protein precipitation procedure was used for compound extraction. Samples were run on an Acquity UPLC BEH C18 column (1.7 μm, 2.1 × 50 mm) following a gradient elution method using a mobile phase consisting of water containing 0.1% (v/v) formic acid and acetonitrile. The method was applied to the analysis of plasma and brain homogenate samples from preclinical pharmacokinetic studies in CD-1 mice. MCI-77 exhibited high systemic clearance (8.5 ± 0.3 L/h/kg) and extensive tissue distribution indicated by a high volume of distribution (20.1 ± 0.3 L/kg). The concentration levels were consistently higher in brain samples than in plasma (brain/plasma AUC ratio 2.9), indicating its ability to cross the blood-brain barrier.

Simultaneous measurement of upadacitinib and methotrexate by UPLC-MS/MS and its pharmacokinetic application in rats

Upadacitinib, as a selective and reversible Janus kinase (JAK) inhibitor, has been widely used in the treatment of atopic dermatitis, ulcerative colitis and other inflammatory bowel diseases and other immune-mediated diseases. The combination of methotrexate and upadacitinib is a common clinical treatment strategy for rheumatoid arthritis (RA) in recent years. In this study, we established an ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) assay for quantitative measurement of upadacitinib and methotrexate, by which we successfully determined pharmacokinetic parameters of them in rat plasma. In order to pretreat the samples, we used acetonitrile as the precipitant, and for the internal standard (IS), we chose tofacitinib. The Acquity BEHC18 (2.1 mm × 50 mm, 1.7 μm) column, with acetonitrile and 0.1% formic acid aqueous solution composed mobile phases, was used to separate upadacitinib, methotrexate and tofacitinib. A Xevo TQ-S triple quadrupole tandem mass spectrometer was used as the detecting instrument in the positive ion mode. For upadacitinib, excellent linearity was shown of this assay in the calibration range with 0.1-200 ng/mL, and as for methotrexate, the range was 0.05-100 ng/mL. As the results indicated, the lower limit of quantification (LLOQ) was respectively 0.1 and 0.05 ng/mL for upadacitinib and methotrexate, the intra- and inter-day precision were ≤ 13.3%, and the accuracy of all the analytes ranged from -4.1% to 12.7%. The recovery of each analyte was > 80.2% in this experiment, and matrix effects we observed were unobvious. The establishment of this method and its successful application in rat plasma can provide a theoretical and technical support for the deeper study of pharmacodynamics and the clinical medication strategies.

Recent Advances in the Development of Sigma Receptor Ligands as Cytotoxic Agents: A Medicinal Chemistry Perspective

Since their discovery as distinct receptor proteins, the specific physiopathological role of sigma receptors (σRs) has been deeply investigated. It has been reported that these proteins, classified into two subtypes indicated as σ₁ and σ₂, might play a pivotal role in cancer growth, cell proliferation, and tumor aggressiveness. As a result, the development of selective σR ligands with potential antitumor properties attracted significant attention as an emerging theme in cancer research. This perspective deals with the recent advances of σR ligands as novel cytotoxic agents, covering articles published between 2010 and 2020. An up-to-date description of the medicinal chemistry of selective σ₁R and σ₂R ligands with antiproliferative and cytotoxic activities has been provided, including major pharmacophore models and comprehensive structure–activity relationships for each main class of σR ligands.

Development of New Benzylpiperazine Derivatives as σ1 Receptor Ligands with in Vivo Antinociceptive and Anti-Allodynic Effects

σ-1 receptors (σ1R) modulate nociceptive signaling, driving the search for selective antagonists to take advantage of this promising target to treat pain. In this study, a new series of benzylpiperazinyl derivatives has been designed, synthesized, and characterized for their affinities toward σ1R and selectivity over the σ-2 receptor (σ2R). Notably, 3-cyclohexyl-1-{4-[(4-methoxyphenyl)methyl]piperazin-1-yl}propan-1-one (15) showed the highest σ1R receptor affinity (Ki σ1 = 1.6 nM) among the series with a significant improvement of the σ1R selectivity (Ki σ2/Ki σ1= 886) compared to the lead compound 8 (Ki σ2/Ki σ1= 432). Compound 15 was further tested in a mouse formalin assay of inflammatory pain and chronic nerve constriction injury (CCI) of neuropathic pain, where it produced dose-dependent (3-60 mg/kg, i.p.) antinociception and anti-allodynic effects. Moreover, compound 15 demonstrated no significant effects in a rotarod assay, suggesting that this σ1R antagonist did not produce sedation or impair locomotor responses. Overall, these results encourage the further development of our benzylpiperazine-based σ1R antagonists as potential therapeutics for chronic pain.