Development and Validation of an Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry Method for Quantitative Determination of N-((3S,4S)-4-(3,4-Difluorophenyl)piperidin-3-yl)-2-fluoro-4-(1-methyl-1H-pyrazol-5-yl)benzamide in Dog Plasma

The PI3K/AKT/MTOR signalling pathway plays an important role in the growth and proliferation of tumour cells. N-((3S,4S)-4-(3,4-Difluorophenyl)piperidin-3-yl)-2-fluoro-4-(1-methyl-1H-pyrazol-5-yl)benzamide (Hu7691) is a new-generation selective AKT inhibitor developed at Zhejiang University. In this study, we developed an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the measurement of Hu7691 in dog plasma. Plasma was precipitated with acetonitrile and then separated on a trifunctionally bonded alkyl column. Excellent separation efficiency and selectivity were achieved by adjusting the mobile phase ratio, with a total running time of only 5 min. The linear dynamic range of the calibration curve was 5–1000 ng/mL. The method was fully validated, and all performance metrics met the criteria. The validated method was used for the pharmacokinetic monitoring and bioavailability assessment of Hu7691 in dogs. The results showed that the area under the curve and peak plasma concentration of Hu7691 increased with increasing dose (oral 5, 10, 20 mg/kg, intravenous 10 mg/kg), and oral bioavailabilities were 86.7%, 50.8%, and 50.5%, respectively, indicating a high bioavailability of Hu7691 in dogs. This provides a test basis for the clinical application of the compound.

(+)-9-Trifluoroethoxy-α-Dihydrotetrabenazine as a Highly Potent Vesicular Monoamine Transporter 2 Inhibitor for Tardive Dyskinesia

Valbenazine and deutetrabenazine are the only two therapeutic drugs approved for tardive dyskinesia based on blocking the action of vesicular monoamine transporter 2 (VMAT2). But there exist demethylated inactive metabolism at the nine position for both them resulting in low availability, and CYP2D6 plays a major role in this metabolism resulting in the genetic polymorphism issue. 9-trifluoroethoxy-dihydrotetrabenazine (13e) was identified as a promising lead compound for treating tardive dyskinesia. In this study, we separated 13e via chiral chromatography and acquired R,R,R-13e [(+)-13e] and S,S,S-13e [(−)-13e], and we investigated their VMAT2-inhibitory activity and examined the related pharmacodynamics and pharmacokinetics properties using in vitro and in vivo models (+)-13e displayed high affinity for VMAT2 (Ki = 1.48 nM) and strongly inhibited [3H]DA uptake (IC50 = 6.11 nM) in striatal synaptosomes. Conversely, its enantiomer was inactive. In vivo, (+)-13e decreased locomotion in rats in a dose-dependent manner. The treatment had faster, stronger, and longer-lasting effects than valbenazine at an equivalent dose. Mono-oxidation was the main metabolic pathway in the liver microsomes and in dog plasma after oral administration, and glucuronide conjugation of mono-oxidized and/or demethylated products and direct glucuronide conjugation were also major metabolic pathways in dog plasma. O-detrifluoroethylation of (+)-13e did not occur. Furthermore, CYP3A4 was identified as the primary isoenzyme responsible for mono-oxidation and demethylation metabolism, and CYP2C8 was a secondary isoenzyme (+)-13e displayed high permeability across the Caco-2 cell monolayer, and it was not a P-glycoprotein substrate as demonstrated by its high oral absolute bioavailability (75.9%) in dogs. Thus, our study findings highlighted the potential efficacy and safety of (+)-13e in the treatment of tardive dyskinesia. These results should promote its clinical development.

The Effect of Posaconazole and Isavuconazole on the Pharmacokinetics of Erdafitinib in Beagle Dogs by UPLC-MS/MS

Objective: A robust, quick, and reliable ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) method for the quantification of erdafitinib in beagle dog plasma was developed and validated to evaluate the changes of posaconazole and isavuconazole on the pharmacokinetics of erdafitinib in beagle dogs, respectively.Methods: This experiment adopted a three-period self-control experimental design. In the first period (group A), erdafitinib was orally administered to six beagle dogs at a dose of 4 mg/kg. In the second period (group B), the same six beagle dogs were orally given posaconazole at a dose of 7 mg/kg, and after 30 min, erdafitinib was orally given. In the third period (group C), isavuconazole at a dose of 7 mg/kg was given orally, and then, erdafitinib was orally given. At the different time points after erdafitinib was given in the three periods, the blood samples were collected. The concentration of erdafitinib was detected by the developed UPLC-MS/MS method. DAS 2.0 was used to calculate the pharmacokinetic parameters of erdafitinib.Results: Erdafitinib had a good linear relationship in the range of 1–500 ng/ml, and the lower limit of quantification was 1 ng/ml. The precision, accuracy, extraction recovery, matrix effect, and stability meet the requirements of the guiding principles. After erdafitinib was combined with posaconazole, the Cmax and AUC0→t of erdafitinib increased by 27.19% and 47.62%, respectively, and the t1/2 was prolonged to 6.33 h. After erdafitinib was combined with isavuconazole, the Cmax and AUC0→t of erdafitinib increased by 23.13% and 54.46%, respectively, and the t1/2 was prolonged to 6.31 h.Conclusion: A robust and reliable UPLC-MS/MS method was fully optimized and developed to detect the plasma concentration of erdafitinib in beagle dogs. Posaconazole and isaconazole could inhibit the metabolism of erdafitinib in beagle dogs and increase the plasma exposure of erdafitinib.

Effect of Sijunzi Pills on Pharmacokinetics of Omeprazole in Beagle Dogs by HPLC-UV: A Herb-Drug Interaction Study

A sensitive high-performance liquid chromatography (HPLC-UV) method for determination of omeprazole in beagle dog plasma was developed and to investigate the effect of Sijunzi pills (SJZPs) on the pharmacokinetics of omeprazole in beagle dogs. The beagle dog plasma was extracted with ethyl acetate and n-hexane under alkaline conditions. Omeprazole and internal standard (IS, fluconazole) were separated on an XDB-C18 column, and acetonitrile and 0.1% trifluoroacetic acid were used as the mobile phase. Omeprazole and IS were detected by using a diode array detector. This experiment adopts the experimental design of double-cycle self-control. In the first cycle (group A), six beagle dogs were given omeprazole 0.67 mg/kg orally in a single dose. In the second period (group B), the same six beagle dogs were orally given SJZPs 0.2 g/kg twice a day for 7 consecutive days, and then, omeprazole was orally given. At the different time points after omeprazole was given in the two periods, the blood samples were collected. The concentration of omeprazole was detected by the developed HPLC method. DAS 2.0 was used to calculate the pharmacokinetic parameters of omeprazole. Under the current experimental conditions, this UPLC method showed good linearity in the detection of omeprazole. Interday and intraday precision did not exceed 10%, and the range of accuracy values were from −1.43% to 2.76%. The results of extraction recovery and stability met the requirements of FDA approval guidelines of bioanalytical method validation. The Cmax of omeprazole in group B was 61.55% higher than that in group A, and the AUC(0−t) and AUC(0−∞) of omeprazole in group B were 63.96% and 63.65% higher those that in group A, respectively. At the same time, the clearance (CL) and apparent volume of distribution (Vd) decreased in group B. In this study, an HPLC method for the determination of plasma omeprazole concentration was established. SJZPs could inhibit the metabolism of omeprazole and increase the concentration of omeprazole in beagle dogs. It is suggested that when SJZPs are combined with omeprazole, attention should be paid to the herb-drug interactions and possible adverse reactions.