Development of gas chromatography/mass spectrometry following headspace solid-phase microextraction for fast determination of asarones in plasma

GC-MS method for determination and pharmacokinetic study of four phenylpropanoids in rat plasma after oral administration of the essential oil of Acorus tatarinowii Schott rhizomes

ETHNOPHARMACOLOGICAL RELEVANCE

Acorus tatarinowii Schott (AT), belong to the family Araceae, is perennial herbaceous plant mainly present in China, Japan and India. The rhizomes of AT have been used as a famous traditional Chinese medicine for the treatment of central nervous system related diseases.

AIM OF THE STUDY

A selective, accurate and sensitive method using gas chromatography-mass spectroscopy (GC-MS) for the simultaneous determination and pharmacokinetic study of β-asarone, α-asarone, elemicin and cis-methyl isoeugenol in rat plasma was developed and validated.

MATERIALS AND METHODS

The GC-MS system was operated under selected ion monitoring (SIM) mode. The samples were prepared by protein precipitation with acetonitrile after being spiked with an internal standard (1-naphthol). The GC separation was achieved on a DB-1701 column (60 m × 0.25 mm ID, and 0.25 µm film thickness).

RESULTS

The current GC/MS assay was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery and stability. The analyte calibration curves were linear over a wide concentration range and the lowest limit of quantifications (LLOQ) were 5.53 ng/mL (β-asarone), 6.50 ng/mL (α-asarone), 3.10 ng/mL (elemicin) and 7.60 ng/mL (cis-methyl isoeugenol). After oral administration 0.9 g /Kg of AT rhizomes, the maximum plasma concentration (Cmax) was 2508.6±498.7 ng/mL for β-asarone, 257.5±37.1 ng/mL for α -asarone, 345.5±33.4 ng/mL for elemicin and 452.7±59.1 ng/mL for cis-methyl isoeugenol, respectively. The time to reach the maximum plasma concentration (Tmax) was 1.42±0.18 h for β-asarone, 1.58±0.19 h for α -asarone, 1.67±0.24 h for elemicin and 1.75±0.38 h for cis-methyl isoeugenol, respectively.

CONCLUSION

This paper described a simple, sensitive and validated GC-MS method for simultaneous determination of four phenylpropanoids in rat plasma after oral administration of the essential oil of AT rhizomes and investigated on their pharmacokinetics studies as well.

Solid phase microextraction and related techniques for drugs in biological samples

In drug discovery and development, the quantification of drugs in biological samples is an important task for the determination of the physiological performance of the investigated drugs. After sampling, the next step in the analytical process is sample preparation. Because of the low concentration levels of drug in plasma and the variety of the metabolites, the selected extraction technique should be virtually exhaustive. Recent developments of sample handling techniques are directed, from one side, toward automatization and online coupling of sample preparation units. The primary objective of this review is to present the recent developments in microextraction sample preparation methods for analysis of drugs in biological fluids. Microextraction techniques allow for less consumption of solvent, reagents, and packing materials, and small sample volumes can be used. In this review the use of solid phase microextraction (SPME), microextraction in packed sorbent (MEPS), and stir-bar sorbtive extraction (SBSE) in drug analysis will be discussed. In addition, the use of new sorbents such as monoliths and molecularly imprinted polymers will be presented.

Simultaneous Determination of Volatile Constituents from Acorus tatarinowii Schott in Rat Plasma by Gas Chromatography-Mass Spectrometry with Selective Ion Monitoring and Application in Pharmacokinetic Study

A sensitive and specific gas chromatographic-mass spectrometry with selected ion monitoring (GC-MS/SIM) method has been developed for simultaneous identification and quantification of α -asarone, β-asarone, and methyl eugenol of Acorus tatarinowii Schott in rat plasma. Chromatographic separation was performed on a Restek Rxi-5MS capillary column (30 m × 0.32 mm × 0.25 μm), using 1-naphthol as internal standard (IS). MS detection of these compounds and IS was performed at m/z 178, 208, 208, and 144. Intra- and interday precisions of all compounds of interest were less than 10%. The recoveries are situated in the range of 92.4-105.2%. Pharmacokinetics of methyl eugenol confirmed to be one-compartment open model, α -asarone and β -asarone was two-compartment open model, respectively. The method will probably be an alternative to simultaneous determination and pharmacokinetic study of volatile ingredients in Acorus tatarinowii Schott.

A rapid HPLC-ESI-MS/MS method for determination of β-asarone, a potential anti-epileptic agent, in plasma after oral administration of Acorus calamus extract to rats

β-Asarone (BAS), a phenylpropanoid from Acorus calamus Linn., has shown biological effects in the management of cognitive impairment conditions such as Alzheimer's disease. The present paper describes a selective and sensitive liquid chromatography-tandem mass spectrometric method (HPLC-MS/MS) using electrospray ionization source (ESI) for quantification of BAS in rat plasma. Briefly, the plasma samples were pre-treated using a simple solid-phase extraction method. The separation of BAS and the internal standard, caffeine, was achieved on an Agilent Zorbax XDB C(18) column (50 × 2.1 mm i.d., 5 µm) using 0.2 mL/min isocratic mobile phase flow. The detection was performed using an Applied Biosystems Hybrid Q-Trap API 2000 mass spectrometer equipped with an ESI source operated in positive mode. Also, the developed bioanalytical method was validated as per the US FDA bioanalytical guidelines over the concentration range of 9.79-4892.50 ng/mL (r(2) ≥ 0.9951) for BAS from rat plasma. The mean percentage recovery (n = 3) for the low, middle and high quality control samples was 86.92 ± 3.89, 85.30 ± 1.09 and 87.24 ± 4.03%, respectively. The applicability of the validated HPLC-MS/MS method was demonstrated by successful measurement of BAS from plasma following oral administration of Acorus calamus rhizome extracts to three female albino Wistar rats.

Analytical methods used in conjunction with solid-phase microextraction: a review of recent bioanalytical applications

Integration of sampling and sample preparation with various analytical instruments is a highly desirable feature for any analytical method. This is most conveniently achieved by using microextraction techniques or various microdevices. Among these techniques, solid-phase microextraction (SPME) is particularly remarkable due to its simplicity and effectiveness. This review discusses the most recent applications of SPME in bioanalysis, grouped according to the analytical instrument that SPME is coupled to. It is shown that one of the most important aspects of such analytical methods is the ability of SPME to perform direct and selective extraction of analytes from complex biological samples. By far, the most popular method continues to be SPME coupled to GC. Nevertheless, the last 2 years have witnessed significant advances in other areas, such as successful automation of SPME coupled to liquid chromatography and the development of new coatings suitable for direct extraction from biological samples. Furthermore, a few bioanalytical applications based on direct coupling of SPME to MS, ion mobility spectrometry, CE and analytical chemiluminescence have been reported.

Traditional Chinese medicine and separation science

Traditional Chinese medicines (TCMs) are getting more and more popular nowadays in the whole world for improving health condition of human beings as well as preventing and healing diseases. TCM is a multi-component system with components mostly unknown, and only a few compounds are responsible for the pharmaceutical and/or toxic effects. The large numbers of other components in the TCM make the screening and analysis of the bioactive components extremely difficult. So, separation and analysis of the desired chemical components in TCM are very important subjects for modernization research of TCM. Thus, many novel separation techniques with significant advantages over conventional methods were introduced and applied to separation and analysis of the chemical constituents in TCM. This review presents just a brief outline of the applications of different separation methods for the isolation and analysis of TCM constituents.

Determination of methylmalonic acid and glutaric acid in urine by aqueous-phase derivatization followed by headspace solid-phase microextraction and gas chromatography-mass spectrometry

In this work, a novel technique of aqueous-phase derivatization followed by headspace solid-phase microextraction and gas chromatography-mass spectrometry was developed for the determination of organic acids in urine. The analytical procedure involves derivatization of organic acids to their ethyl esters with diethyl sulfate, headspace sampling, and GC/MS analysis. The proposed method was applied to the determination of methylmalonic acid and glutaric acid in urine. The experimental parameters and method validation were studied. Optimal conditions were obtained: PDMS fiber, extraction temperature 55 degrees C, extraction time 30 min, and 60 microL of diethyl sulfate as derivatization reagent with 2 mg of the ion pairing agent tetrabutylammonium hydrogensulfate. The method was linear over three orders of magnitude, and detection limits were 21 nM for methylmalonic acid and 34 nM for glutaric acid, respectively. Consequently, in-situ derivatization/HS-SPME/GC/MS is an alternative and powerful method for determination of organic acids as biomarkers in biological fluids.

Fast determination of paeonol in plasma by headspace solid-phase microextraction followed by gas chromatography–mass spectrometry

Paeonol is the active component in the traditional Chinese medicines (TCMs), such as Cynanchum paniculatum, which has been used to treat many diseases, such as eczema. In this work, a simple, rapid and sensitive method was developed for the determination of paeonol in rabbit plasma, which was based on headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS). The extraction parameters of fiber coating, sample temperature, extraction time, stirring rate and ion strength were systemically optimized; the method linearity, detection limit and precision were also investigated. It was shown that the proposed method provided a good linearity (0.02-20 microg mL(-1), R(2)>0.990), low detection limit (2.0 ng mL(-1)) and good precision (R.S.D. value less than 8%). Finally, GC/MS following HS-SPME was applied to fast determination of paeonol in rabbit plasma at different time point after oral demonstration of Cynanchum paniculatum essential oil. The experimental results suggest that the proposed method provided an alternative and novel approach to the pharmacokinetics study of paeonol in the TCMs.