Quantitative analysis of tivantinib in rat plasma using ultra performance liquid chromatography with tandem mass spectrometry.

In this work, a simple, sensitive and fast ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitative determination of tivantinib in rat plasma. Plasma samples were processed with a protein precipitation. The separation was achieved by an Acquity UPLC BEH C18 (2.1mm×50mm, 1.7µm) column with a gradient mobile phase consisting of 0.1% formic acid in water and acetonitrile. Detection was carried out using positive-ion electrospray tandem mass spectrometry via multiple reaction monitoring (MRM). The validated method had an excellent linearity in the range of 1.0-100ng/mL (r(2)>0.9967) with a lower limit of quantification (1.0ng/mL). The extraction recovery was in the range of 79.4-84.2% for tivantinib and 80.3% for carbamazepine (internal standard, IS). The intra- and inter-day precision was below 8.9% and accuracy was from -7.2% to 9.5%. No notable matrix effect and astaticism was observed for tivantinib. The method has been successfully applied to a pharmacokinetic study of tivantinib in rats for the first time, which provides the basis for the further development and application of tivantinib.

Determination of rivaroxaban, apixaban and edoxaban in rat plasma by UPLC-MS/MS method.

To establish a rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the determination of rivaroxaban, apixaban and edoxaban in rat plasma. The analytes and the internal standard (diazepam) were separated on an Acquity UPLC BEH C18 chromatography column (2.1 mm × 50 mm, 1.7 µm) using gradient elution with a mobile phase of acetonitrile and 0.1 % formic acid in water at a flow rate of 0.4 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring mode to monitor the precursor-to-product ion transitions of m/z 436.1 â†’ 145.1 for rivaroxaban, m/z 460.0 â†’ 443.1 for apixaban, m/z 548.2 â†’ 366.1 for edoxaban and m/z 285.2 â†’ 193.1 for diazepam (IS) using a positive electrospray ionization interface. The method was validated over a concentration range of 1.0-200 ng/mL for rivaroxaban, 1.0-100 ng/mL for apixaban and 1.0-500 ng/mL for edoxaban. Total time for each chromatograph was 3.5 min. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels exhibited relative standard deviations <10.5 % and the accuracy values ranged from -9.9 to 11.3 %. The method was successfully applied to a pharmacokinetic study of rivaroxaban, apixaban and edoxaban in rats.

Effects of Evodiamine on the Pharmacokinetics of Dapoxetine and Its Metabolite Desmethyl Dapoxetine in Rats.

The objective of this work was to investigate the effect of orally administered evodiamine on the pharmacokinetics of dapoxetine and its active metabolite desmethyl dapoxetine in rats. Twelve healthy male Sprague-Dawley rats were randomly divided into 2 groups: the control group (received oral 10 mg/kg dapoxetine alone) and the combination group (10 mg/kg dapoxetine orally co-administered with 100 mg/kg evodiamine). The plasma concentration of dapoxetine and desmethyl dapoxetine were estimated by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and different pharmacokinetic parameters were calculated using the Drug and Statistics 2.0 software. Compared to the control group, the pharmacokinetic parameter of t1/2, AUC(0-∞) and Tmax of dapoxetine in combination group was significantly increased by 63.3% (p < 0.01), 44.8% (p < 0.01) and 50.4% (p < 0.01), respectively. Moreover, evodiamine had significantly decreased the pharmacokinetic parameter of t1/2 and AUC(0-∞) of desmethyl dapoxetine. This study demonstrated that evodiamine inhibits the metabolism of dapoxetine. Henceforth, the pharmacodynamic influence of this interaction should be taken into consideration while prescribing dapoxetine to the patients already taking evodiamine.

[Screening and identification of phage-displayed polypeptides specifically binding to human gastric cancer with high metastatic potential to peritoneum].

OBJECTIVE: By means of phage-display technique, to screen polypeptides that specifically bind to human gastric cancer with high metastatic potential to peritoneum. METHODS: Two human gastric cancer cell lines were used: GC9811-P with high metastatic potential to peritoneum and its wild type parental GC9811, to carry out subtractive screening with a phage display-12 peptide library. RESULTS: After three rounds of screening, 40 phage clones bond to GC9811-P cells were randomly selected. When injected into the peritoneal cavity of nude mice, 6 of the 40 clones did not bind to mouse peritoneum as examined by immunohistochemical staining. They were considered to be capable of binding specifically to GC9811-P cells. Sequence analysis revealed two different exogenous peptides: TLNINRLILPRT and SMSI(X)SPYI(XXX). CONCLUSION: Two peptides have been obtained that specifically bind to a gastric cancer cell variant GC9811-P, which easily disseminates to the peritoneum. Whether or not they could block GC9811-P metastasis to peritoneum in vivo remains to be determined.

[Osteopontin expression and its relation to invasion and metastases in gastric cancer].

OBJECTIVE: To investigate the correlation between expression of the osteopontin (OPN) and invasion and metastases in gastric cancer. METHODS: The expression of OPN, NF-kappaB p65 and matrix metallo-proteinase 9 (MMP-9) was detected by immunohistochemistry in non-cancer gastric tissue (n = 12 cases) and gastric cancer tissue (n = 72 cases). RESULTS: (1) OPN, NF-kappaB p65 and MMP-9 were not expressed in 12 non-cancer gastric tissue samples(group A). Their expression rates were 43.3%, 40.0% and 46.7% respectively in 30 gastric cancer samples without lymph nodes metastasis (group B), but they increased to 76.9%, 73.1% and 80.8% in 26 gastric cancer samples with lymph nodes metastases (group C), and 87.5%, 81.3% and 93.8% respectively in 16 gastric cancer samples with lymph node and distant metastases (group D). (2) There were statistically significant differences in their expressions between group D and group B (P(a) = 0.004, P(c) = 0.007, P(e) = 0.002), and between group C and group B (P(b) = 0.011, P(d) = 0.013, P(f) = 0.009). (3) Despite some differences in positive expression rates, correlations existed between OPN and NF-kappaB p65, and between NF-kappaB p65 and MMP-9 (P(1) = 0.042, P(2) = 0.013; r(1)= 0.67, r(2)= 0.72). CONCLUSION: Osteopondin espression is closely related to the invasion and metastases of gastric cancer. It may upregulate the expression of metastasis-related molecule MMP-9 by activating NF-kappaB pathway.

[Effect and significance of anisodamine on IkappaB kinase-beta in Kupffer cells following hemorrhagic shock].

OBJECTIVE: To investigate the possible role of IkappaB kinase-beta (IKK-beta), the pathogenesis of hepatic injury induced by resuscitation of hemorrhagic shock and endotoxin, and to evaluate the preventive effect of anisodamine (654-2). METHODS: Twenty-seven rabbits were randomly divided into the normal group, hemorrhagic shock plus endotoxin group and 654-2 treatment group. The expression of IKK-beta, activity of the nuclear factor-kappaB (NF-kappaB) in Kupffer cells (KC) and the concentration of tumor necrosis factor-alpha (TNF-alpha) in the culture supernatant were measured by in situ hybridization (ISH), electrophoretic mobility shift assay (EMSA) and enzyme linked immunoadsorbent analysis (ELISA), respectively. The pathological changes in the hepatic tissue were examined with light microscope. RESULTS: Compared with the normal group, the expression of IKK-beta (0.21+/-0.03), the activity of NF-kappaB (2.29+/-0.25) in KC, and the level of TNF-alpha[(560.21+/-31.04) ng/L] in the culture supernatant of KC were obviously increased after hemorrhagic shock and endotoxin(all P<0.01 ). 654-2 treatment could significantly inhibit the expression of IKK-beta (0.14+/-0.03) and the activity of NF-kappaB (1.35+/-0.17) in KC, decrease the content of TNF-alpha [(300.79+/-23.47) ng/L] in the culture supernatant of KC in rabbits with hemorrhagic shock plus endotoxin challenge (all P<0.01 ),and alleviate hepatic injury as observed by histological examination. CONCLUSION: IKK-beta expression in KC could be enhanced after hemorrhagic shock and endotoxin, and it might play an important role in the development and progression of hepatic injury following hemorrhagic shock and endotoxin. 654-2 could inhibit IKK-beta expression, decrease NF-kappaB activation and cytokine secretion in KC after hemorrhagic shock followed by resuscitation and endotoxin. The inhibition of IKK-beta expression might be a protective mechanism for hepatic injury.