Xenobiotica最新文献

Atorvastatin, an effective lipid-lowering drug, could reduce the risks of morbidity and mortality of cardiovascular diseases. Patients with cardiovascular diseases often use atorvastatin along with berberine. Atorvastatin is the substrate of CYP3A4 and P-gp. However, berberine is the inhibitor. The combination might lead to DDIs. The aim of this study was to assess the effect of berberine on pharmacokinetics and pharmacodynamics of atorvastatin in rats.Plasma concentrations of atorvastatin with or without berberine were determined by HPLC. Pharmacokinetics parameters were calculated and used to evaluate pharmacokinetics interactions. The effect of berberine on pharmacodynamics of atorvastatin was investigated by detecting blood lipid, SOD, MDA, GSH-Px, AST, ALT, and liver histopathology.C_max, t_max, and AUC_0-t of atorvastatin in combination group significantly increased both in normal and model rats (p < 0.01). The increase of t_1/2, AUC_0-t in model rats was more significant than that in normal rats (p < 0.05). Pharmacodynamics indexes in treatment groups were significantly improved, especially combination group (p < 0.05). Moreover, it could be found that there is a significant recovery in liver histopathology.In conclusion, berberine could affect pharmacokinetics of atorvastatin, enhance lipid-lowering effect and improve liver injury in rats. More attention should be paid to plasma exposure in clinical to avoid adverse reactions.

C. officinalis Kuan is the dry root of Cyathula officinalis Kuan. Clinically, it is used for fall and flutter injury, rheumatism and arthralgia. Phytoecdysteroids have significant anti-inflammatory effects, and the phytoecdysteroids present in C. officinalis Kuan exhibit potential for treating rheumatoid arthritis.This study first developed a selective, accurate and efficient LC-MS/MS method for 12-day pharmacokinetic studies regarding the simultaneous determination of cyasterone, 25-epi-28-epi-cyasterone, precyasterone and capitasterone from C. officinalis Kuan phytoecdysteroids extract in normal and adjuvant arthritis rats.An Agilent Eclipse Plus C₁₈ RRHD column (1.8 µm, 50mm × 2.1 mm) with a gradient mobile phase consisting of water (A) and acetonitrile (B) was used for analysis. The mass analysis was performed in an Agilent 6430 QQQ-MS mass spectrometer with positive mode multiple reaction monitoring (MRM).The results indicated that the AUC_0-t and AUC_0-∞ values of the four phytoecdysteroids in adjuvant arthritis rats were different from those in normal rats on the first day, which could provide a helpful reference for pharmacological and toxicological studies, as well as clinical applications of C. officinalis Kuan in the treatment of rheumatoid arthritis.

The in vitro metabolism of hirsutine was determined using liver microsomes and human recombinant cytochrome P450 enzymes. Under the current conditions, a total of 14 phase I metabolites were tentatively identified.Ketoconazole showed significant inhibitory effect on the metabolism of hirsutine. Human recombinant cytochrome P450 enzyme analysis revealed that metabolism of hirsutine was mainly catalysed by CYP3A4.Our data revealed that hirsutine was metabolised via mono-oxygenation, di-oxygenation, N-oxygenation, dehydrogenation, demethylation and hydrolysis.In glutathione (GSH)-supplemented liver microsomes, four GSH adducts were identified. Hirsutine underwent facile P450-mediated metabolic activation, forming reactive 3-methyleneindolenine and iminoquinone intermediates.This study provided valuable information on the metabolic fates of hirsutine in liver microsomes, which would aid in understanding the hepatotoxicity caused by hirsutine or hirsutine-containing herb preparation.

N, N-dimethyltryptamine (DMT) is a psychedelic compound that has shown potential in the treatment of depression. Aside from the primary role of monoamine oxidase A (MAO-A) in DMT metabolism, the metabolic pathways are poorly understood. Increasing this understanding is an essential aspect of ensuring safe and efficacious use of DMT.This work aimed to investigate the cytochrome 450 (CYP) mediated metabolism of DMT by incubating DMT with recombinant human CYP enzymes and human liver microsomes (HLM) followed by analysis using high-resolution mass spectrometry for metabolite identification.DMT was rapidly metabolised by CYP2D6, while stable with all other investigated CYP enzymes. The metabolism of DMT in HLM was reduced after inclusion of harmine and SKF-525A whereas quinidine did not affect the metabolic rate, likely due to MAO-A residues present in HLM. Analysis of the CYP2D6 incubates showed formation of mono-, di- and tri-oxygenated metabolites, likely as a result of hydroxylation on the indole core.More research is needed to investigate the role of this metabolic pathway in vivo and any pharmacological activity of the proposed metabolites. Our findings may impact on safety issues following intake of ayahuasca in slow CYP2D6 metabolizers or with concomitant use of CYP2D6 inhibitors.

Evobrutinib is a highly selective, covalent, central nervous system-penetrant Bruton's tyrosine kinase (BTK) inhibitor, currently in Phase III trials for the treatment of relapsing multiple sclerosis. One major circulating metabolite of evobrutinib has been previously identified as the racemic dihydro-diol M463-2 (MSC2430422) in a Phase I human mass balance study.Phenotyping experiments were conducted to confirm the metabolic pathway of evobrutinib to M463-2. Ratio of the enantiomers was determined by enantioselective liquid chromatography with tandem mass spectrometry analysis of plasma samples from humans and preclinical species. Drug-drug interaction (DDI) characterisation, evaluation of pharmacological activity on BTK, and off-target screening experiments followed assessing safety of the metabolite.The biotransformation of evobrutinib to M463-2 was determined to be a two-step process with a CYP-mediated oxidation acting to form an epoxide intermediate, which was further hydrolysed by soluble and mitochondrial epoxide hydrolase. Only the (S)-enantiomer was determined to be a major metabolite, the (R)-enantiomer was minor. In vitro studies demonstrated the (S)-enantiomer lacked clinically relevant pharmacological activity, off-target effects and DDIs.The biotransformation of evobrutinib to its major metabolite has been elucidated, with the major (S)-enantiomer being shown to pose no on/off target or DDI risks.

The pharmacokinetic (PK) and toxicokinetic profile of a drug from its preclinical evaluation helps the researcher determine whether the drug should be tested in humans based on its safety and toxicity.Preclinical studies require time and resources and are prone to error. Moreover, according to the United States Food and Drug Administration Modernisation Act 2, animal testing is no longer mandatory for new drug development, and an animal-free alternative, such as cell-based assay and computer models, can be used.Different physiologically based PK models were developed for an anaplastic lymphoma kinase inhibitor in rats and monkeys after intravenous and oral administration using its physicochemical properties and in vitro characterisation data.The developed model was validated against the in vivo data available in the literature, and the validation results were found within the acceptable limit. A parameter sensitivity analysis was performed to identify the properties of the compound influencing the PK profile.This work demonstrates the application of the physiologically based PK model to predict the PKs of a drug, which will eventually assist in reducing the number of animal studies and save time and cost of drug discovery and development.