Effects of the ABCB1 and ABCG2 polymorphisms on the pharmacokinetics of afatinib in healthy Chinese volunteers.

1. Afatinib is an oral, selective tyrosine kinase inhibitor (TKI) primarily transported by P-glycoprotein (MDR1, gene code ABCB1) and breast cancer resistance protein (BCRP, gene code ABCG2). In the present study, the effects of ABCB1 and ABCG2 genetic polymorphisms on the pharmacokinetics of afatinib in healthy Chinese were investigated.2. Blood samples from 24 healthy participants who received afatinib were used for genotyping ABCB1 (1236C>T, 2677G > T/A, 3435C>T) and ABCG2 (34G>A, 421C>A) polymorphisms. Subsequently, the association between afatinib plasma concentrations and target single-nucleotide polymorphisms (SNPs) was analyzed.3. Among the five polymorphisms, plasma concentrations of afatinib in healthy subjects with ABCB1 1236CC-3435CC were remarkably higher than in other genotype subjects. No significant differences of afatinib exposure were found between the ABCG2 wild-type and heterozygous groups.4. The ABCB1 genetic polymorphism influenced the plasma exposure of afatinib, and gene testing before drug administration may be useful for clinically individualized use of afatinib. Our data suggest the usefulness of afatinib pharmacogenetics in treatment optimization.

ABCC2 c.-24 C>T single-nucleotide polymorphism was associated with the pharmacokinetic variability of deferasirox in Chinese subjects.

PURPOSE: Our aim was to evaluate the influence of genetic polymorphisms involved in the metabolism and transportation of deferasirox on deferasirox pharmacokinetics in the Chinese population. METHODS: Thirty-eight healthy Chinese subjects were administered with a single dose of 20 mg kg-1 deferasirox. Allelic discriminations for eight single-nucleotide polymorphisms (SNPs) in UDP-glucuronosyltransferase 1A1, 1A3 (UGT1A1, UGT1A3), multidrug resistance protein 2 (MRP2, ABCC2), and breast cancer resistance protein (BCRP, ABCG2) were performed. The concentrations of deferasirox in the plasma were determined by UPLC-MS/MS. RESULTS: Subjects carrying ABCC2 c.-24 T allele had a 65% higher clearance (CL/F) and 42% lower area under the concentration-time curve from 0 to 72 h (AUC0-72h) as compared with non-carriers (P = 0.008, P = 0.011, respectively). ABCC2 c.-24 T was also associated with 59% shorter half-life (T1/2) and 17% shorter mean residence time (MRT) (P = 0.030, P = 0.014, respectively). ABCC2 1249A was associated with a marginal increase in deferasirox Cmax (P = 0.07). Genetic polymorphisms of UGT1A1, UGT1A3, and ABCG2 did not significantly influence the pharmacokinetics of deferasirox. Subjects with UGT1A1 211GG-(-1352)CC-(-3156)GG haplotype had higher AUC0-72h than others. Since only two subjects were recruited in the GG-CC-GG group, further confirmative studies were warranted. CONCLUSIONS: ABCC2 c.-24 C>T was associated with the pharmacokinetic variability of deferasirox in Chinese subjects. This study revealed an important role of MRP2 in the pharmacokinetics of deferasirox and drew attention to drug combination with MRP2 inhibitors like cyclosporine and methotrexate in deferasirox therapy.

Permeability and transport mechanism of trihexyphenidyl hydrochloride in Caco-2 cell monolayer model with a validated UPLC-MS/MS method.

A rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was applied to investigate the permeability characteristics and transport mechanism of trihexyphenidyl hydrochloride (TH) in D-hanks with the Caco-2 cells model. Analytes were separated using an Zorbax Extend-Agilent C18 (1.8 µm, 4.6 × 30 mm) column following a simple methanol precipitation treatment. The mobile phase consisted of methanol and water containing 0.1% formic acid, and the total gradient program time was 1.5 min. Method validation results showed TH was linear in 2-500 ng/mL (r2 > 0.99), and the lower limit of quantification (LLOQ) was 2 µg/mL. The intra-run and inter-run precision (coefficient of variation, CV) was within 2.80%, and the accuracy (relative error, RE) was within ±11.10%. Stability of TH was evaluated in different storage conditions, including short-term I-III, long-term I-III, 2 and 4 h in the artificial gastrointestinal tract, respectively. There was no obvious interference between TH and internal standards (IS). With the established Caco-2 monolayer permeability model, Papp(AB) of TH was calculated as 46.29 ±â€¯8.31 × 10-6 cm/s, and the efflux ratio (ER) value was calculated as 0.22, indicating a high permeability character of TH. The transmembrane transport of TH followed the concentration-dependent, temperature-independent, and energy-free manner. Collectively, these characteristics indicate that TH is a highly permeable drug and the transport mechanism is mainly via passive diffusion.

Fructus Gardeniae-induced gastrointestinal injury was associated with the inflammatory response mediated by the disturbance of vitamin B6, phenylalanine, arachidonic acid, taurine and hypotaurine metabolism.

ETHNOPHARMACOLOGICAL RELEVANCE: Fructus Gardenia (FG) is a widely used bitter and cold herb for clearing heat and detoxicating. Currently, toxicity of FG and its relative formula has been reported in many clinical and animal studies. However, no systematic research has been carried out on FG-related gastrointestinal (GI) injury which has been emphasized in China since the Ming Dynasty. AIM OF THE STUDY: The purpose of this article is to investigate whether FG could damage GI and explore the mechanisms involved. MATERIAL AND METHODS: FG was given to male mice by 7-day intragastric administration at average doses of 0.90 g (L group), 1.50 g (M group), and 3.00 g (H group) crude drug/kg FG. Comprehensive understanding of changes in weight, diarrhea degree, stool routine, histomorphology and inflammatory factors of stomach, small intestine, and colon for evaluating the effect of different doses of FG on GI injury. Moreover, metabolomics-based mechanisms exploration of FG on GI injury was carried out via HPLC-Q-TOF/MS analysis on mice urine. RESULTS: High dose FG caused GI injury with serious diarrhea, decreased weight, abnormal stool routine, sever alteration in histomorphology of small intestine and colon (mild change in stomach), and significant change in inflammatory factors. The results of metabolomics suggested that 55 endogenous metabolites dispersed in 21 significantly altered metabolic pathways in 3.00 g/kg crude FG treated mice. The hub metabolites of GI injury were mainly related with vitamin B6 metabolism, phenylalanine metabolism, arachidonic acid metabolism, and taurine and hypotaurine metabolism via correlated network analysis. CONCLUSION: FG affected the normal functions of GI via the regulating a variety of metabolic pathways to an abnormal state, and our results provided a research paradigm for the GI-injury of the relative bitter and cold traditional Chinese medicines.