Forchlorfenuron (CPPU) is a plant growth regulator extensively used in agriculture. However, studies on CPPU pharmacokinetics are lacking. We established and validated a rapid, sensitive, and accurate liquid chromatography–mass spectrometry method for CPPU detection in rat plasma. CPPU pharmacokinetics was evaluated in adult and juvenile rats orally treated with 10, 30, and 90 mg/kg of the compound. The area under the plasma drug concentration–time curve from 0 to 24 h (AUC), at the final time point sampled (AUC_0–t), and the maximum drug concentration of CPPU increased in a dose-dependent manner. The pharmacokinetic parameters AUC_0–t and absolute bioavailability were higher in the juvenile rats than in adult rats. The mean residence time and AUC_0–t of juvenile rats in the gavage groups, except for the 10 mg/kg dose, were significantly higher in comparison to those observed for adult rats (p < 0.001). The plasma clearance of CPPU in juvenile rats was slightly lower than that in the adult rats. Taken together, juvenile rats were more sensitive to CPPU than adult rats, which indicates potential safety risks of CPPU in minors.

Dalbavancin is a novel semisynthetic glycopeptide antibiotic that comprises multiple homologs and isomers of similar polarities. However, pharmacokinetic studies have only analyzed the primary components of dalbavancin, namely B₀ and B₁. In this study, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to simultaneously determinate and investigate the five homologous components of dalbavancin, namely, A₀, A₁, B₀, B₁, and B₂, in rat plasma. In this method, methanol was used to precipitate plasma, and a triple-bonded alkyl chromatographic column was used for molecule separation, using 0.1% formic acid-acetonitrile as the mobile phase for gradient elution. Targeted homologs were analyzed by a triple quadrupole mass spectrometer using positive electrospray ionization in multiple reaction monitoring mode. The linearity range was 50–2500 ng/mL with a high correlation coefficient (r² > 0.998). This method was successfully applied in the pharmacokinetic analysis of dalbavancin hydrochloride to investigate dalbavancin components in rats.

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.