Characterization of CGK012 in rat plasma by high performance liquid chromatography and mass spectrometry (HPLC–MS/MS): Application to a pharmacokinetic study

Quantitative determination of ICG-001 in rat plasma using HPLC-MS/MS: A pharmacokinetic study

Although ICG-001, chemically synthesised from a bicyclic β-turn peptidomimetic template, represents various pharmacological activities, no validated determination methods in biological samples have been reported. This study was designed to establish a quantitative determination method for ICG-001 in rat plasma using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) to validate the analytical method, including stability, and to characterise its pharmacokinetic behaviour in rats. After simple protein precipitation with acetonitrile, ICG-001 was eluted on a reversed-phase column using a mobile phase of water and acetonitrile (3:7 v/v, including 0.1% formic acid). The protonated precursor ion [M+H]⁺ and the major fragment ion were confirmed at m/z 549.2 and 141.4, respectively, for ICG-001. ICG-001 was stable under bench and storage conditions. The analytical method met the criteria for Food and Drug Administration-validated bioanalytical methods, and was successfully applied to a pharmacokinetic study for the first time following subcutaneous and intravenous administration.

Absolute oral and subcutaneous bioavailability of ortho-topolin riboside in mice

Among essential phytohormones playing a pivotal role in regulating growth and development, ortho-topolin riboside (oTR) exerts the most substantial anti-tumor potency in various cancer cell lines. This study was designed to establish a quantitative determination method for oTR in mouse plasma using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS), to validate the analytical method including stability, and to characterise its pharmacokinetic behaviour in mice. After simple protein precipitation with acetonitrile including kinetin riboside (internal standard), oTR was eluted on a reversed-phase column using a mobile phase of water and acetonitrile (3:7 v/v, including 0.1% formic acid). The protonated precursor ion [M+H]⁺ and major fragment ion were confirmed at m/z 374.06 and 241.99 for oTR, and 348.23 and 216.06 for the IS, respectively. oTR was stable under bench and storage conditions. The analytical method met the criteria of FDA-validated bioanalytical methods and was successfully applied to a pharmacokinetic study for the first time following oral, subcutaneous, and intravenous administrations. While oTR was merely absorbed by an oral route, 90% of the absolute subcutaneous bioavailability was observed.

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.

A sensitive analytical method for the determination of SG-SP1 in rat plasma by HPLC-MS/MS and its application to a pharmacokinetic study

SG-SP1, a newly synthesised gallic acid derivative, blocks histamine release by reducing calcium influx in mast cells and inhibits inflammatory cytokine expression. This derivative has promising anti-allergic potential. Our research was designed to establish a quantitative determination method for SG-SP1 in rat plasma using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS), to validate the analytical method including stability and to characterise its pharmacokinetic behaviour in rats. After simple protein precipitation with acetonitrile including an internal standard, SG-SP1 was eluted on a reversed-phase column using a mobile phase of water and acetonitrile (2:8 v/v, including 0.1 % formic acid). The protonated precursor ion [M+H]⁺ and major fragment ion were confirmed at m/z 588.2 and 180.1, respectively. The substance was stable under bench and storage conditions. The analytical method met the criteria of FDA-validated bioanalytical methods and was successfully applied to a pharmacokinetic study for the first time. SG-SP1 decayed in a biphasic pattern with terminal half-life of 5.1 h and clearance of about 3.2 L/h/kg. Double peaks were observed following oral administration, and the absolute oral bioavailability was ∼1 %.