Development of a UHPLC-MS/MS method for the quantification of ilaprazole enantiomers in rat plasma and its pharmacokinetic application

Stereoselectivity of evodiamine enantiomers in neuroprotective activity, pharmacokinetics and the ability across the blood-brain barrier

Evodiamine, a chiral quinazoline alkaloid in the traditional Chinese medicine Evodiae fructus, exhibited efficacy for CNS diseases. In this study, the pure enantiomers of evodiamine were prepared in large quantities via chemical resolution. Their structures were elucidated by MS, NMR and ECD. The optical purity was determined to be as high as 99.8 %. The differences of the enantiomers in protective effect against neuronal cell injury were evaluated using MTT assay. Notably, R-(-)-evodiamine showed better neuroprotection effects against H2O2-induced damage in PC12 cells. An efficient HPLC-MS/MS method for determination of evodiamine enantiomers in rat plasma and brain was developed and verified. Satisfactory enantioseparation of evodiamine was achieved on a Chiralcel OD-RH column with the mobile phase of acetonitrile-water (70:30, v/v) at a flow rate of 0.6 mL/min. The analytes were measured under multiple reactions monitoring (MRM) mode with m/z 304.3→134.3 for evodiamine and m/z 289.3→97.1 for testosterone (IS) using electrospray ionization source (ESI) in the positive ion mode. The method was validated and fulfilled the requirements of bioanalysis. It was successfully applied to study the stereoselectivity of evodiamine in pharmacokinetics and the ability across the blood-brain barrier in rats. After oral and intravenous administration of racemic evodiamine to rat, the area under the concentration-time curve of R-evodiamine was noticeably 1.70 and 1.33 times higher than those of S-evodiamine, respectively. Furthermore, while there was no significant difference in the B/P values, the concentration of R-(-)-evodiamine in the brain was approximately 1.31 times greater than that of S-(+)-evodiamine. The results indicated that evodiamine enantiomers exhibited significant stereoselectivity in pharmacokinetics after oral administration and intravenous administration. While the two enantiomers showed no significant stereoselectivity in the ability across the blood-brain barrier. These findings provided new insights into the development of a single enantiomer of evodiamine as a potential drug candidate for the treatment of CNS diseases.

Progress of Pretreatment and Analytical Methods of Proton Pump Inhibitors: An Update since 2010

Proton pump inhibitors (PPIs) are the most commonly used medication for stomach secretion disorders. However, when it comes to safe, discreet pharmaceutical practice, widely recognized preparational and analytical method(s) for PPIs with sensitivity, selectivity, speed and high accuracy still remains underdeveloped. For this reason, this paper sets out to make a comprehensive review of the preparation and determination methods for PPIs based on multiple matrices since 2010. We have integrated newly-developed techniques (such as solid phase extraction, liquid phase micro-extraction, and solid phase micro-extraction) into conventional sample preparational methods. On the other hand, our analytical techniques include liquid chromatography, supercritical fluid chromatography, capillary electrophoresis, and employment of sensors. In addition, we have identified the pros and cons of each technique and have forecast their future developmental trends.

Advances and challenges in the pharmacokinetics and bioanalysis of chiral drugs

Enantioselective analytical approaches are essential for monitoring pharmacokinetics and acquiring accurate data to better understand the role of stereochemistry in pharmacokinetics. Enantioselectivity significantly impacts the pharmacokinetics of chiral drugs, especially in metabolic profile, leading to toxicity of enantiomer. Consequently, there is a need to study the pharmacokinetics of enantiomerically pure drugs and racemates as they differ in affinity with enzymes and proteins. Combining the best enantioseparation conditions with the specified biological matrix and the intended purpose of the analysis is a challenging task. This review discusses the importance of chirality in stereoselective pharmacokinetics with more relevant examples, various enantioselective analytical techniques, and stationary phases employed. Challenges such as lack of universal chiral columns, biological inversion of the isomers, and others have been discussed. Further presented the recent advances in the screening of chiral drugs and innovative improvements in the analytical approaches for chiral molecule analysis such as supercritical fluid chromatography, simulated moving bed chromatography, and other techniques are discussed.

An overview of chiral separations of pharmaceutically active substances by HPLC (2018-2020)

This review provides a brief survey of chiral separation of pharmaceutically active substances published over the last 3 years (2018-2020). Chiral separation of drugs is an important area of research. The control of enantiomeric purity and determination of individual enantiomeric drug molecules is a necessity especially for clinical, analytical, and regulatory purposes. Among chromatographic resolution methods, high-performance liquid chromatography based on chiral stationary phases remains the most popular and effective method used for chiral separation of various drugs. In this review, attention is paid to several classes of chiral stationary phases that have been the most frequently used for drug enantioseparation during this period.

GRAPHIC ABSTRACT

Chiral separation in the class of proton pump inhibitors by chromatographic and electromigration techniques: An overview

Proton pump inhibitors (PPIs) are benzimidazole-derivative chiral sulfoxides, frequently used in the treatment of gastric hyperacidity-related disorders. Due to their stereoselective metabolism, the eutomeric forms of PPIs can present a more advantageous pharmacokinetic profile by comparison with the distomers or racemates. Moreover, two representatives of the class are used in therapy both as racemates and as pure enantiomers (esomeprazole, dexlansoprazole). A relatively large number of enantioseparation methods employed for the stereoselective determination of PPIs from pharmaceutical, biological, and environmental matrices were published in the past three decades. The purpose of the current overview is to provide a systematic survey of the available chiral separation methods published since the introduction of PPIs in the therapy up to the present. Analytical and bioanalytical methods using different chromatographic and electromigration techniques reported for the enantioseparation of omeprazole, lansoprazole, pantoprazole, rabeprazole, ilaprazole, and tenatoprazole are included. The analytical conditions of the presented methods are summarized in three comprehensive tables, while a critical discussion of the applied techniques, possible mechanism of enantiorecognition, and future perspectives on the topic are also presented.

Quantitative Determination of Quercitrin Levels in Rat Plasma Using UHPLC-MS/MS and its Application in a Pharmacokinetic Study after the Oral Administration of Polygoni Cuspidati Folium Capsules

BACKGROUND

Quercitrin is widely found in herbal medicines, and it is particularly important in the design of new therapeutic agents. Because of its wide range of biological activities, methods for detecting quercitrin and its pharmacokinetics in biological samples must be investigated.

OBJECTIVE

To develop and validate a sensitive and reliable ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the quantitative determination of quercitrin levels in rat plasma and test its application in a pharmacokinetic investigation after the oral administration of Polygoni cuspidati folium capsules (HC).

METHODS

First, a rapid analytical method implementing UHPLC-MS/MS for the quantification of quercitrin levels in rat plasma was developed and validated. The analyte and internal standard (IS) tinidazole were extracted from rat plasma via protein precipitation with 800 μL of methanol and 50 μL of 1% formic acid solution. Chromatographic separation was performed using an Agilent ZORBAX C18 column within 4 min. Mass spectrometry was performed for quantification using a triple-quadrupole mass spectrometer employing electrospray ionization in the negative ion mode. The MRM transitions for quercitrin and IS were m/z 447.2→229.9 and m/z 246.0→125.8, respectively. The UHPLC-MS/MS method for the quantitative determination of quercitrin levels in rat plasma was then applied to investigate its pharmacokinetics after the oral administration of HC in rats.

RESULTS

The developed UHPLC-MS/MS method for detecting quercitrin in rat plasma was linear over the range of 0.1-160 ng/mL. The linear regression equation was Y = (0.7373 ± 0.0023)X - (0.0087 ± 0.0021) (r2 = 0.9978). The intra- and interday precision values were within 7.8%, and the recoveries of quercitrin and IS exceeding 67.3%. The UHPLC-MS/MS method was successfully applied to characterize the pharmacokinetic profile of quercitrin in eight rats after the oral administration of HC. The experimentally obtained values were fit to a one-compartment, first-order pharmacokinetic model, and they appeared to fit the concentration-time curve.

CONCLUSION

Quercitrin was proven to be stable during sample storage, preparation, and analytical procedures. The pharmacokinetic parameters suggested that quercitrin may be present in the peripheral tissues of rats.

Enantiomeric Separation of Dioxopromethazine and its Stereoselective Pharmacokinetics in Rats by HPLC-MS/MS

Dioxopromethazine (DPZ) is a popular phenothiazine antihistamine that is widely used as a racemic drug in clinical to cure respiratory illness. In our work, a reliable, specific, and rapid enantioselective HPLC-MS/MS method has been established and fully validated for the quantification of R- and S-DPZ in rat plasma. After plasma alkalization (with 1 M Na₂CO₃), DPZ enantiomers and diphenhydramine (IS) were extracted using ethyl acetate. Completely separation of R- and S-DPZ (Rs = 2.8) within 12 min was implemented on Chiralpak AGP column (100 × 4.0 mm i.d., 5 μm) employing ammonium acetate (10 mM; pH 4.5) - methanol (90:10, v/v) as mobile phase. Themultiple reaction monitoring (MRM) mode was used for the detection of DPZ enantiomers and IS. The transitions of m/z 317.2 → 86.1 and 256.2 → 167.1 werechosen for monitoring DPZ enantiomers and IS, respectively. Good linearity (r² > 0.995) was achieved for each DPZ enantiomer over the linear ranges of 1.00 - 80.00 ng/mL, with the lower limit of quantitation (LLOQ) of 1.00 ng/mL. The intra-day and inter-day precisions (RSDs,%) were below 12.3%, and accuracies (REs,%) were in the scope of-10.5% to 6.6%, which were within the admissible criteria. The validated bioanalytical approach was applied to the stereoselective pharmacokinetic (PK) research of DPZ in rat plasma for the first time. It was found that significant differences (p < 0.05) exist between the main PK parameters of R- and S-DPZ, indicating the pharmacokinetic behaviors of DPZ enantiomers in rats were stereoselective. The chiral inversion of the enantiomers did not occur during the assay.