Effects of Dexmedetomidine on the Pharmacokinetics of Dezocine, Midazolam and Its Metabolite 1-Hydroxymidazolam in Beagles by UPLC-MS/MS

Strain differences in the drug transport capacity of intestinal glucose transporters in Sprague-Dawley versus Wistar rats, C57BL/6J versus Kunming mice

Designing oral drug delivery systems using intestinal glucose transporters (IGTs) may be one of the strategies for improving oral bioavailability of drugs. However, little is known about the biological factors affecting the drug transport capacity of IGTs. Gastrodin is a sedative drug with a structure very similar to glucose. It is a highly water-soluble phenolic glucoside. It can hardly enter the intestine through simple diffusion but exhibits good oral bioavailability of over 80%. We confirmed that gastrodin is absorbed via the intestinal glucose transport pathway. It has the highest oral bioavailability among the reported glycosides' active ingredients through this pathway. Thus, gastrodin is the most selective drug substrate of IGTs and can be used to evaluate the drug transport capacity of IGTs. Obviously, strain is one of the main biological factors affecting drug absorption. This study firstly compared the drug transport capacity of IGTs between SD rats and Wistar rats and between C57 mice and KM mice by pharmacokinetic experiments and single-pass intestinal perfusion experiments of gastrodin. Then, the sodium-dependent glucose transporter type 1 (SGLT1) and sodium-independent glucose transporters type 2 (GLUT2) in the duodenum, jejunum, ileum and colon of these animals were quantified using RT-qPCR and Western blot. The results showed that the oral bioavailability of gastrodin in Wistar rats was significantly higher than in SD rats and significantly higher in KM mice than in C57 mice. Gastrodin absorption significantly differed among different intestinal segments in SD rats, C57 mice and KM mice, except Wistar rats. RT-qPCR and Western blot demonstrated that the intestinal expression distribution of SGLT1 and GLUT2 in SD rats and C57 mice was duodenum ≈ jejunum > ileum > colon. SGLT1 expression did not differ among different intestinal segments in KM mice, whereas the intestinal expression distribution of GLUT2 was duodenum ≈ jejunum ≈ ileum > colon. However, the expression of SGLT1 and GLUT2 did not differ among different intestinal segments in Wistar rats. It was reported that the intestinal expression distribution of SGLT1 and GLUT2 in humans is duodenum > jejunum > ileum > colon. Hence, the intestinal expression distribution of SGLT1 and GLUT2 of SD rats and C57 mice was more similar to that in humans. In conclusion, the drug transport capacity of IGTs differs in different strains of rats and mice. SD rats and C57 mice are more suitable for evaluating the pharmacokinetics of glycosides' active ingredients absorbed via the intestinal glucose transport pathway.

Simultaneous Determination of Celecoxib, Dezocine and Dexmedetomidine in Beagle Plasma Using UPLC-MS/MS Method and the Application in Pharmacokinetics

Background

An efficient, fast and sensitive ultra high-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method for simultaneous determination of celecoxib (CEL), dezocine (DEZ) and dexmedetomidine (DEX) in beagle plasma were established.

Methods

The beagle dogs plasmawas precipitated by acetonitrile. The column was Acquity UPLC BEH C18 column and the mobile phase was acetonitrile-formic acid with gradient mode, and the flow rate was set at 0.4 mL/min. Under the positive ion mode, CEL, DEZ, DEX and Midazolam (internal standard, IS) were monitored by multiple reaction monitoring (MRM) as the following mass transition pairs: m/z 381.10→282.10 for CEL, m/z 246.20→147.00 for DEZ, m/z 201.10→94.90 for DEX, and m/z 326.10→291.10 for IS.

Results

This UPLC-MS/MS method had good linearity for CEL, DEZ and DEX. The RSDs of inter-day and intra-day precision were the values of 0.31–7.66% and 0.11–9.63%, respectively; the RE values were from −6.05% to 10.98%. The extraction recovery was more than 79%, and the matrix effect was around 100%. The RSDs of stability were less than 8.96%. All of them met the acceptance standard of biological analysis method recommended by FDA.

Conclusion

This UPLC-MS/MS method is an effective tool for the simultaneous determination of CEL, DEX and DEX, and has been successfully applied to the study of pharmacokinetics in beagle dogs.

Establishment and Verification of UPLC-MS/MS Technique for Pharmacokinetic Drug-Drug Interactions of Selinexor with Posaconazole in Rats

Background

A method for the determination of selinexor by UPLC-MS/MS was established to study the effect of posaconazole on the pharmacokinetics of selinexor in rats.

Methods

The experiment rats were divided into group A (0.5% CMC-Na) and group B (posaconazole, 20 mg/kg), 6 rats in each group. 30 minutes after administration of 0.5% CMC-Na or posaconazole, all the rats were given selinexor (8 mg/kg), and plasma samples were collected. The plasma samples underwent acetonitrile protein precipitation, and were separated by UPLC on an Acquity UPLC BEH C18 column with gradient elution. Acetonitrile and 0.1% formic acid were used as the mobile phases. The analyte detection was used a Xevo TQ-S triple quadrupole tandem mass spectrometer and multiple reaction monitoring (MRM) for analyte monitoring. We use acetonitrile for protein precipitation.

Results

Selinexor had good linearity (1.0-1000 ng/mL, r² ₌0.996 2), and the accuracy and precision, recovery rate and matrix effects(ME) were also met the FDA approval guidelines. Compared with group A, the C_max, AUC_(0-t) and AUC_(0-∞) of selinexor in group B increased by 60.33%, 48.28% and 48.27%, and T_max increased by 53.92%, CLz/F reduced by 32.08%.

Conclusion

This bioanalysis method had been applied to the study of drug interactions in rats. It was found that posaconazole significantly increased the concentration of selinexor in rats. Therefore, when selinexor and posaconazole are combined, we should pay attention to the possible drug-drug interactions to reduce adverse reactions.

Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry for Simultaneous Determination of Antipsychotic Drugs in Human Plasma and Its Application in Therapeutic Drug Monitoring

PURPOSE

We developed and validated an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneous therapeutic drug monitoring (TDM) and clinical pharmacokinetic antipsychotic drugs: clozapine (CLP), chlorpromazine (CPZ), risperidone (RPD), paliperidone (PLD), quetiapine (QTP;), aripiprazole (APZ), dehydroaripiprazole (DAP), olanzapine (OZP), ziprasidone (ZRD), and amisulpride (ASP).

METHODS

Analytes and internal standards (ISs) were separated using a Phenomenex phenyl-hexyl column (50.0 × 2.1 mm, 1.7 μm) with water containing 0.1% formic acid and 2 mM ammonium acetate, and methanol containing 0.1% formic acid and 2 mM ammonium acetate as the mobile phase. The antipsychotic drugs and ISs were extracted from 50 μL of plasma using acetonitrile.

RESULTS

The calibration ranges were 25.0-1500.0 ng/mL for CLP, CPZ, DAP, and QTP, 10.0-600.0 ng/mL for CPZ and ZRD, 2.5-150.0 ng/mL for RPD, 5.0-300.0 ng/mL for PLD and OZP, and 20.0-1200.0 ng/mL for ASP. Validation was carried out according to the guidelines for bioanalytical validation, including assessment of calibration curves, specificity, accuracy, precision, recovery, stability, dilution integrity, and matrix effect. All the results satisfied the requirements.

CONCLUSION

The results provided significant information to support future clinical TDM and rational drug use research. The proposed method also provided a simple, reliable, specific, and suitable technique for TDM and pharmacokinetic studies.