Simultaneous determination of Rivaroxaban and TAK-438 in rat plasma by LC-MS/MS: application to pharmacokinetic interaction study

Selection of Specific Aptamer against Rivaroxaban and Utilization for Label-Free Electrochemical Aptasensing Using Gold Nanoparticles: First Announcement and Application for Clinical Sample Analysis

For the first time, a novel aptamer was designed and utilized for the selective detection of rivaroxaban (RIV) using the integration of bioinformatics with biosensing technology. The selected aptamer with the sequence 5'-TAG GGA AGA GAA GGA CAT ATG ATG ACT CAC AAC TGG ACG AAC GTA CTT ATC CCC CCC AAT CAC TAG TGA ATT-3' displayed a high binding affinity to RIV and had an efficient ability to discriminate RIV from similar molecular structures. A novel label-free electrochemical aptasensor was designed and fabricated through the conjugation of a thiolated aptamer with Au nanoparticles (Au-NPs). Then, the aptasensor was successfully applied for the quantitative determination of RIV in human plasma and exhaled breath condensate (EBC) samples with limits of detection (LODs) of 14.08 and 6.03 nM, respectively. These valuable results provide ample evidence of the green electrogeneration of AuNPs on the surface of electrodes and their interaction with loaded aptamers (based on Au-S binding) towards the sensitive and selective monitoring of RIV in human plasma and EBC samples. This bio-assay is an alternative approach for the clinical analysis of RIV and has improved specificity and affinity. As far as we know, this is the first time that an electrochemical aptasensor has been verified for the recognition of RIV and that allows for the easy, fast, and precise screening of RIV in biological samples.

Determination of Rivaroxaban in Rat Plasma by UHPLC-Q-Orbitrap HRMS and Its Application to A Pharmacokinetic Study

Therapeutic drug monitoring is critical to decrease the incidence rate of bleeding and thrombosis for personalized treatment of rivaroxaban, especially for drug interaction treatment, renal dysfunction patients, elderly patients, cardiovascular patients, and so on. And, an accuracy analytical method is necessary to therapeutic drug monitoring. This study developed a ultra high performance liquid chromatography-tandem orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) method to accurately identify and quantify rivaroxaban in rat plasma. Isotope internal standard method was applied for accurate quantification. And rivaroxaban-d₄ was selected as isotope internal standard substance. The m/z 436.07263 ([M+H]⁺ ) was selected as precursor ions and the m/z 144.95085, 231.11259 were selected as main product ions for rivaroxaban. The LLOQ of rivaroxaban in plasma was 0.01 mg/L. The intra- and inter-day precisions were ≤3.65 % and ≤8.16 %. And the recoveries were ranged from 87.4% to 95.2%. This analysis method was simple, low cost, and easy to operation and applied successfully to a pharmacokinetic study of rivaroxaban in rat plasma. This analysis method could be helpful to promote further research on the mechanism of rivaroxaban and drug interaction, which can avoid the false positives due to its high precision identification.

Evaluation of Herb–Drug Interaction Between Danshen and Rivaroxaban in Rat and Human Liver Microsomes

The combination of Salvia miltiorrhiza (Danshen) and rivaroxaban is a promising treatment option in clinical practice in China, but the herb–drug interaction between Danshen and rivaroxaban remains unclear. Therefore, this study aims to reveal the interaction between Danshen and rivaroxaban. We not only investigated the inhibitory properties of Danshen tablet on rivaroxaban metabolism in rat and human liver microsomes but also evaluated the inhibitory effects of Danshen tablet and its eight active components (dihydrotanshinone I, tanshinone I, tanshinone IIA, cryptotanshinone, danshensu, salvianolic acid A, salvianolic acid B, and salvianolic acid C) on cytochrome P450 (CYP) enzymes. The results showed that Danshen tablet potently inhibited the metabolism of rivaroxaban in rat and human liver microsomes. In the CYP inhibition study, we found that dihydrotanshinone I, the active component of Danshen tablet, potently inhibited the activities of rat CYP3A and CYP2J, with IC₅₀ values at 13.85 and 6.39 μM, respectively. In further inhibition kinetic study, we found that Danshen tablet is a mixed inhibitor in rivaroxaban metabolism in rat and human liver microsomes, with the K_i value at 0.72 and 0.25 mg/ml, respectively. In conclusion, there is a potential interaction between Danshen tablet and rivaroxaban. Danshen tablet inhibits the metabolism of rivaroxaban, which may be because its lipid-soluble components such as dihydrotanshinone I strongly inhibit the activities of CYP enzymes, especially CYP3A and CYP2J. Therefore, when Danshen tablet and rivaroxaban are used simultaneously in the clinic, it is necessary to strengthen the drug monitoring of rivaroxaban and adjust the dosage.

The Development and Optimization of Hot-Melt Extruded Amorphous Solid Dispersions Containing Rivaroxaban in Combination with Polymers

Rivaroxaban (RXB), a novel oral anticoagulant that directly inhibits factor Xa, is a poorly soluble drug belonging to Biopharmaceutics Classification System (BCS) class II. In this study, a hot-melt extruded amorphous solid dispersion (HME-ASD) containing RXB is prepared by changing the drug:polymer ratio (Polyvinylpyrrolidione-vinyl acetate 64, 1:1–1:4) and barrel temperature (200–240 °C), fixed at 20% of Cremophor^® RH 40 and 15 rpm of the screw speed, using the hot-melt extruding technique. This study evaluates the solubility, dissolution behavior, and bioavailability for application to oral drug delivery and optimizes the formulation of rivaroxaban amorphous solid dispersion (RXB-ASD). Based on a central composite design, optimized RXB-ASD (PVP VA 64 ratio 1:4.1, barrel temperature 216.1 °C, Cremophor^® RH 40 20%, screw speed 15 rpm) showed satisfactory results for dependent variables. An in vitro drug dissolution study exhibited relatively high dissolution in four media and achieved around an 80% cumulative drug release in 120 min. Optimized RXB-ASD was stable under the accelerated condition for three months without a change in crystallinity and the dissolution rate. A pharmacokinetic study of RXB-ASD in rats showed that the absorption was markedly increased in terms of rate and amount, i.e., the systemic exposure values, compared to raw RXB powder. These results showed the application of quality by design (QbD) in the formulation development of hot-melt extruded RXB-ASD, which can be used as an oral drug delivery system by increasing the dissolution rate and bioavailability.

Development of a ultra-performance LC-MS/MS method for quantification of GW788388 and its applications in pharmacokinetic study in rats

Aim: GW788388 is a selective and orally active TGF-β1 receptor inhibitor that shows potent activity in renal fibrosis. We aimed to establish and validate a simple and sensitive ultra-performance LC-MS/MS method for the determination of GW788388 in plasma samples. Methodology & results: GW788388 in rat plasma was processed with protein precipitation method and then separated on a C₁₈ column. The calibration curve presented a good linearity in the range of 1.0-1200 ng/ml, with satisfactory accuracy (relative error, [-17.5% < relative error <11.7%) and precision (CV <8.9%) for all quality control samples. After oral administration, GW788388 was absorbed quickly and reached a peak concentration of 595.3 ± 60.2 ng/ml after 20 min. Conclusion: The validated method provides a quantification method of GW788388 in rat plasma in detail, and can be utilized to successfully describe the pharmacokinetic profile of GW788388.