An enhanced strategy integrating offline two-dimensional separation with data independent acquisition mode and deconvolution: Characterization of metabolites of Uncaria rhynchophylla in rat plasma as a case.

The importance to clarify the drug metabolites is beyond doubt in view of their potential efficacy and safety. However, due to the complex matrix interference, relatively low content and the co-eluting effect, it is of a great challenge to comprehensively and systematically characterize the metabolites in vivo, especially for the traditional Chinese medicines (TCMs) due to the numerous types of components. In the present study, a comprehensive off-line two-dimensional separation system combining with data independent acquisition (DIA) mode and multi-dimensional data deconvolution method was established for chromatographic separation, data acquisition and data procession of indole alkaloids in rat plasma after intragastrically administrated with the extract of Uncaria rhynchophylla at the dose of 1 g/kg. The orthogonality of the off-line 2D separation system consisting of HILIC for first-dimensional separation and the PRLC for second-dimensional separation was valuated with the "asterisk" equations, and the results showed that off-line 2D separation system had passable orthogonality (A0 = 53.3%). Furthermore, the DIA mode was applied to capture MS/MS spectra in view of its advantage in acquiring MS data, and an effective multi-dimensional deconvolution method integrating the calculation of chemical formula, the extraction of diagnostic ion, the filter of ring double bond (RDB) and the judgement of neutral loss was established to parse the spectra for the complicated DIA data for comprehensive analysis of metabolites in rat plasma. Ultimately, a total of 127 indole alkaloids were tentatively characterized, and the main metabolic pathways were inferred as demethylation, dehydrogenation, hydroxylation and deglycosylation. The off-line two-dimensional separation system was applied for the comprehensive characterization of metabolites in vivo for the first time. This study suggested a new approach to enable the enrichment, separation and analysis of the low content components in vivo.

Simultaneous determination of five alkaloids from Rauvolfia vomitoria in rat plasma by LC-MS/MS: Application to a comparative pharmacokinetic study in normal and type 2 diabetic rats.

Rauvolfia vomitoria is widely distributed in the tropical regions of Africa and Asia, and has been used in traditional folk medicine in China. Indole alkaloids were found to be major bioactive components, while the effects of diabetes mellitus on the pharmacokinetic parameters of the components have not been reflected in vivo. In this study, an efficient and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of five ingredients of R. vomitoria in rats. Detection was implemented in multiple-reaction-monitoring mode with an electrospray positive-ionization source. Validation parameters were all in accordance with the current criterion. The established method was effectively employed to compare the pharmacokinetic behaviors of five alkaloids (reserpine, yohimbine, ajmaline, ajmalicine, and serpentine) between normal and type 2 diabetic rats. The single-dose pharmacokinetic parameters of the five alkaloids were determined in normal and diabetic rats after oral administration of 100 and 200 mg/kg body weight. The results indicated that diabetes mellitus significantly altered the pharmacokinetic characteristics of yohimbine, ajmaline, and ajmalicine after oral administration in rats. This is an attempt to provide some evidence for clinicians that may serve as a guide for the use of antidiabetic medicine in clinical practice.

Gender differences in plasma pharmacokinetics and hepatic metabolism of geissoschizine methyl ether from Uncaria hook in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Geissoschizine methyl ether (GM), an indole alkaloid from Uncaria hook, is an active ingredient in the traditional Japanese Kampo medicine yokukansan, which is used to treat neurosis, insomnia, irritability, and night crying in children. AIM OF THE STUDY: Recent our pharmacokinetic studies suggested that there may be gender differences in the plasma concentrations of GM in rats, but not in humans. However, the details of this difference remain unverified. The purpose of this study was to clarify the reasons for the gender differences in rats. MATERIALS AND METHODS: GM plasma pharmacokinetics was compared in male and female rats orally administered yokukansan (4 g/kg). To confirm the involvement of cytochrome P450 (CYP) in GM liver metabolism, GM was incubated with male and female rat liver S9 fraction in the absence or presence of 1-aminobenzotriazole (a nonspecific CYP inhibitor). CYP isoforms involved in GM metabolism were estimated using recombinant rat CYP isoforms and anti-rat CYP antibodies. RESULTS: The maximum GM plasma concentrations were significantly higher in female than in male rats. When GM was incubated with rat liver S9 fractions, GM reduction was more striking in male S9 (69.3%) than that in female S9 (10.0%) and was completely blocked with nonspecific CYP inhibitor 1-aminobenzotriazole. Screening experiments using recombinant rat cytochrome P450 (CYP) isoforms showed that CYP1A1, CYP2C6, CYP2C11, CYP2D1, and CYP3A2 were involved in GM metabolism. Of these CYP isoforms, the use of anti-rat CYP antibodies indicated that male-dependent CYP2C11 and CYP3A2 were predominantly involved in the liver microsomal GM metabolism with gender differences. CONCLUSIONS: These results suggest that the cause of gender differences in plasma GM pharmacokinetics in rats is most likely because of male-dependent CYP2C11 and CYP3A2, and provide also useful information to further evaluate the pharmacological and toxicological effects in future. This study is the first to demonstrate that the gender differences in plasma GM pharmacokinetics in rats are caused by the gender-dependent metabolism of GM.

Pharmacokinetics and safety evaluation in healthy Chinese volunteers of alkaloids from leaf of Alstonia scholaris: A multiple doses phase I clinical trial.

BACKGROUND: Alstonia scholaris (Apocynaceae) was reported to be a rich source of indole alkaloids, which exhibited remarkably bioactivities. The leaf of A. scholaris has been used in 'dai' ethno-medicine for treatment of respiratory diseases, and the defined indole alkaloids from leaf of A. scholaris has been registered as investigational new botanical drug (No. 2011L01436) and was approved for phase I/II clinical trials by China Food and Drug Administration (CFDA). PURPOSE: The aim of the trial is to evaluate the safety and explore the relationship of dosing frequency and pharmacokinetics after oral administration of capsule of alkaloids from leaf of A. scholaris (CALAS) at different doses. METHODS: In this randomized, open-labelled, single-center clinical trial, the safety and pharmacokinetics of CALAS were assessed in eligible healthy Chinese volunteers after oral administration of different doses. Each volunteer (n = 10 per group) received single dose of CALAS from 20 mg, 40 mg, 80 mg to 120 mg orally. The pharmacokinetics of CALAS was investigated in healthy Chinese subjects' plasma by a fully-validated LC-MS/MS method. Safety was assessed biochemically and clinically throughout the study, and drug re-excitation research was conducted to verify the correlation between investigational product and minor adverse events. The trial was registered on August 26, 2015 (http://www.chictr.org.cn/showproj.aspx?proj=11736), number ChiCTR-IPR-15006976. RESULTS: 40 subjects completed the study, and as a result, vallesamine had the highest concentration in plasma of healthy volunteers, and the AUC exposure level in each compounds in turn is vallesamine > scholaricine > 19-epischolaricine > picrinine. For the safety evaluation of CALAS, two cases of minor adverse events were observed during the trial, but the drug re-excitation research indicated that these two adverse events were related to the individual's physiological variation. CONCLUSION: Pharmacokinetic characteristics of each ingredient showed different patterns. 19-epischolaricine, vallesamine and picrinine were match to the linear pharmacokinetic characteristics, but scholaricine conformed to the characteristics of nonlinear pharmacokinetics. The CALAS was safe in healthy subjects under the current dose regimen.

LC-MS/MS detection of citrus unshiu peel-derived flavonoids in the plasma and brain after oral administration of yokukansankachimpihange in rats.

1. Yokukansankachimpihange (YKSCH), a Kampo formulation combining Citrus unshiu peel (CUP) and Pinellia tuber (PT) with yokukansan (YKS), has been recently used to treat the behavioral and psychological symptoms of dementia. Several flavonoids derived from CUP and PT reportedly exhibit psychopharmacological activity, but it remains unclear whether these flavonoids reach the brain after oral administration of YKSCH. 2. In this study, we first measured eight target flavonoids in the plasma and brain in rats orally administered YKSCH. Among these flavonoids, hesperidin, narirutin, nobiletin, and heptamethoxyflavone (HMF) were detected in the plasma, and nobiletin and HMF were detected in the brain. 3. Next, to clarify whether CUP and PT affect the pharmacokinetics of YKS ingredients in YKSCH, the plasma pharmacokinetics of geissoschizine methyl ether (GM) as a representative active ingredient in YKS was examined in rats orally administered YKSCH or YKS. There was no significant difference between the two groups, inferring that the pharmacokinetics of GM may not be affected by the two additional crude drugs. 4. Taken together, this study suggests that the CUP-derived flavonoids nobiletin and HMF may be responsible for the psychopharmacological effects of YKSCH in addition to YKS ingredients.

Ultra-Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS)-Based Pharmacokinetics and Tissue Distribution Study of Koumine and the Detoxification Mechanism of Glycyrrhiza uralensis Fisch on Gelsemium elegans Benth.

Gelsemium elegans Benth. (G. elegans), which is a famous Chinese folk medicine, has been commonly used to treat certain types of skin ulcers and alleviate inflammation, headaches, and cancer pain. However, the extensive clinical use of G. elegans has been greatly hampered by its toxicity. As one of the most widely used herbal medicines, Glycyrrhiza uralensis Fisch, has a unique effect on detoxification of G. elegans. In the present study, a rapid and sensitive method using ultra-liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was established and validated for determination of koumine, the most abundant molecule among the alkaloids of G. elegans, in rat plasma, tissue, and liver microsome. The developed method was successfully applied to the pharmacokinetics, tissue distribution, and in vitro metabolism study in rat with or without pre-treated Glycyrrhiza uralensis Fisch extract. Meanwhile, the expression level of CYP3A1 mRNA was analyzed to explain the detoxification mechanism of Glycyrrhiza uralensis Fisch on G. elegans. As a result, our work demonstrated that Glycyrrhiza uralensis Fisch could significantly affect the pharmacokinetics and tissue distribution of koumine in rats. The detoxification mechanism of Glycyrrhiza uralensis Fisch on G. elegans may be its cytochrome enzyme up-regulation effect.

Simultaneous determination of gelsemine and koumine in rat plasma by UPLC-MS/MS and application to pharmacokinetic study after oral administration of Gelsemium elegans Benth extract.

A simple, rapid and sensitive method using UPLC-MS/MS was established and validated for simultaneous determination of gelsemine and koumine in rat plasma after oral administration of Gelsemium elegans Benth extract. Plasma was performed with methanol precipitation and berberine was chosen as the internal standard. Plasma samples were separated on an Acquity UPLC® BEH C18 column (3.0 × 50 mm, 1.7 µm) with gradient elution using acetonitrile and 0.1% formic acid aqueous solution as the mobile phase at a flow rate of 0.4 mL/min. Multiple reaction monitoring mode in positive ion mode was utilized for detection. The calibration curves were linear over the range of 0.2-100 ng/mL for gelsemine and 0.1-50 ng/mL for koumine, with the lower limits of quantification 0.2 and 0.1 ng/mL, respectively. The intra- and inter-precision and accuracy were well within the acceptable ranges. The developed method was successfully applied to an in vivo pharmacokinetic study in rat after oral administration of 10 mg/kg Gelsemium elegans Benth extract.

Differences of first-pass effect in the liver and intestine contribute to the stereoselective pharmacokinetics of rhynchophylline and isorhynchophylline epimers in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Uncaria rhynchophylla (Miq.) Miq. ex Havil., is a plant species used in traditional Chinese medicine to treat cardiovascular and central nervous system diseases. Rhynchophylline (RIN) and isorhynchophylline (IRN), a pair of epimers, are major alkaloids isolated from U. rhynchophylla and exhibit diverse pharmacological effects. Our previous study demonstrated that the pharmacokinetics of these epimers existed stereoselectivity after oral administration; however, the specific mechanism remains unknown and merits investigation. AIM OF THE STUDY: In the present study, the aim was to elucidate the mechanism underlying stereoselective pharmacokinetic characteristics of RIN and IRN in rats. MATERIALS AND METHODS: The total (F), hepatic (Fh) and intestinal (Fa·Fg) bioavailabilities of each epimer were measured using portal vein cannulated rats following different dosing routes (intravenous, intraportal and intraduodenal) to assess individual contributions of the liver and intestine in stereoselective pharmacokinetics. Then the differences of first-pass metabolism in the liver and intestine between two epimers were evaluated by in vitro incubation with rat liver microsomes, intestinal S9 and gastrointestinal (GI) content solutions, respectively. Meanwhile, the membrane permeability and efflux by P-glycoprotein (P-gp) were examined by in situ single-pass intestinal perfusion with and without P-gp inhibitor verapamil. The configurational interconversion at different pH values and the excretions via feces and urine were also examined. RESULTS: Pharmacokinetic data showed that the total bioavailability of RIN was 5.9 folds higher than that of IRN (23.4% vs. 4.0%). The hepatic availability of RIN was 4.6 folds higher than that of IRN (46.9% vs. 10.3%), whereas the intestinal availability of RIN (48.1%) was comparable to that of IRN (42.7%). In addition, intestinal perfusion showed that IRN possessed higher intestinal permeability than RIN and co-perfusion with verapamil could affect absorption process of RIN but not IRN. Conversely, the metabolism rate of IRN in rat liver microsomes was significantly faster than that of RIN, resulting in a lower systemic exposure of IRN after oral administration. The degradation in GI lumen and epimerization between two epimers also existed but had small contributions. Additionally, the excretions of both epimers via feces and urine were negligible. CONCLUSIONS: Taken together, different first-pass metabolism in the liver was the major factor responsible for the stereoselective pharmacokinetics of RIN and IRN.

Detection and characterization of the metabolites of rutaecarpine in rats based on ultra-high-performance liquid chromatography with linear ion trap-Orbitrap mass spectrometer.

CONTEXT: Rutaecarpine is an active indoloquinazoline alkaloid ingredient originating from Evodia rutaecarpa (Wu-zhu-yu in Chinese), which possesses a variety of effects. However, its metabolism has not been investigated thoroughly yet. OBJECTIVE: This study develops a highly sensitive and effective method for detection and characterization of the metabolites of rutaecarpine in Sprague-Dawley (SD) rats. MATERIALS AND METHODS: In this study, an efficient method was developed using ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometer (UHPLC-LTQ-Orbitrap MS) to detect the metabolism profile of rutaecarpine in rat plasma. First, a blood sample (1 mL) was withdrawn 2 h after oral administration of rutaecarpine in SD rats (50 mg/kg). Second, the blood was centrifuged at 4000 rpm for 10 min and pretreated by solid-phase extraction method. Third, 2 µL of the plasma was injected into UHPLC-LTQ-Orbitrap MS for analysis. Finally, the metabolites of rutaecarpine were tentatively identified based on accurate mass measurements, fragmentation patterns and chromatographic retention times. RESULTS: A total of 16 metabolites (four new metabolites, viz., dihydroxylation and sulphate conjugation products of rutaecarpine (M8-M11)) as well as parent drug itself, including three phase I and 12 phase II metabolites were detected and identified in rat plasma. Hydroxylation, sulphate conjugation and glucuronidation were confirmed as the primary metabolic pathways for rutaecarpine in rat plasma. DISCUSSION AND CONCLUSION: These results provide an insight into the metabolism of rutaecarpine and also can give strong indications on the effective forms of rutaecarpine in vivo.

Qualitative screening of absorbed indoloquinazoline alkaloids and their metabolites in rat plasma after the oral administration of Wu-Zhu-Yu decoction by high-resolution mass spectrometry with multiple data mining algorithms.

A rapid and sensitive liquid chromatography with high-resolution mass spectrometry method with multiple data processing algorithms was developed and applied for the metabolite profiling of evodiamine and its analogous alkaloids in rat plasma after the administration of Wu-Zhu-Yu decoction. All samples were purified using hydrophilic-lipophilic balanced solid-phase extraction cartridges and analyzed by a Sciex TripleTOF 5600(+) mass spectrometer with a 35 min liquid chromatography gradient elution. High-resolution full-scan mass spectrometry and information-dependent acquisition tandem mass spectrometry data were analyzed using multiple data processing approaches. The results indicated that the detected eight prototype alkaloids could be metabolized to 58 metabolites through both phase I and phase II reactions. Oxidation was demonstrated to be the principle metabolic pathway of the parent compounds. The study contributes to the understanding of the absorption and metabolism of the alkaloids in Wu-Zhu-Yu decoction and provides a detailed analysis of scientific data.

Pharmacokinetic study of isocorynoxeine metabolites mediated by cytochrome P450 enzymes in rat and human liver microsomes.

Isocorynoxeine (ICN) is one of the major bioactive tetracyclic oxindole alkaloids found in Uncaria rhynchophylla (Miq.) Jacks. that is widely used for the treatment of hypertension, vascular dementia, and stroke. The present study was undertaken to assess the plasma pharmacokinetic characteristics of major ICN metabolites, and the role of simulated gastric and intestinal fluid (SGF and SIF), human and rat liver microsomes (HLMs and RLMs), and seven recombinant human CYP enzymes in the major metabolic pathway of ICN. A rapid, sensitive and accurate UHPLC/Q-TOF MS method was validated for the simultaneous determination of ICN and its seven metabolites in rat plasma after oral administration of ICN at 40mg/kg. It was found that 18.19-dehydrocorynoxinic acid (DCA) and 5-oxoisocorynoxeinic acid (5-O-ICA) were both key and predominant metabolites, rather than ICN itself, due to the rapid and extensive metabolism of ICN in vivo. The further study indicated that ICN was mainly metabolized in human or rat liver, and CYPs 2C19, 3A4 and 2D6 were the major enzymes responsible for the biotransformation of ICN to DCA and 5-O-ICA in human. These findings are of significance in understanding of the pharmacokinetic nature of tetracyclic oxindole alkaloids, and provide helpful information for the clinical co-administration of the herbal preparations containing U. rhynchophylla with antihypertensive drugs that are mainly metabolized by CYP3A4 and CYP2C19.

Pharmacokinetics of Active Components of Yokukansan, a Traditional Japanese Herbal Medicine after a Single Oral Administration to Healthy Japanese Volunteers: A Cross-Over, Randomized Study.

CONTEXT: Yokukansan (YKS) is a traditional Japanese herbal medicine called kampo medicine in Japan. Its extract comprises seven crude drugs: Atractylodis lanceae rhizoma, Poria, Cnidii rhizoma, Uncariae uncis cum ramulus, Angelicae radix, Bupleuri radix, and Glycyrrhizae radix. YKS is used to treat neurosis, insomnia, as well as behavioral and psychological symptoms of dementia. OBJECTIVE: To confirm the exposure and pharmacokinetics of the active components of YKS in healthy volunteers. DESIGN, SETTING, AND PARTICIPANTS: A randomized, open-label, 3-arm, 3-period, crossover trial was conducted on 21 healthy Japanese volunteers at the Kochi Medical University between May 2012 and November 2012. INTERVENTIONS: Single oral administration of YKS (2.5 g, 5.0 g, or 7.5 g/day) during each period. MAIN OUTCOME MEASURE: Plasma concentrations of three active compounds in YKS, namely 18ß-glycyrrhetinic acid (GA), geissoschizine methyl ether (GM), and hirsuteine (HTE). RESULTS: The mean maximum plasma concentrations (Cmax) of GM and HTE increased dose-dependently (ranges: 0.650-1.98 ng/mL and 0.138-0.450 ng/mL, respectively). The times to maximum plasma concentration after drug administration (tmax) were 0.500 h for GM and 0.975-1.00 h for HTE. The apparent elimination half-lives (t1/2) were 1.72-1.95 h for GM and 2.47-3.03 h for HTE. These data indicate the rapid absorption and elimination of GM and HTE. On the other hand, the Cmax, tmax, and t1/2 of GA were 57.7-108 ng/mL, 8.00-8.01 h, and 9.39-12.3 h, respectively. CONCLUSION: We demonstrated that pharmacologically active components of YKS are detected in humans. Further, we determined the pharmacokinetics of GM, HTE, and GA. This information will be useful to elucidate the pharmacological effects of YKS. TRIAL REGISTRATION: Japan Pharmaceutical Information Center JAPIC CTI-121811.

Determination of rhynchophylline and hirsutine in rat plasma by UPLC-MS/MS after oral administration of Uncaria rhynchophylla extract.

An ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to concurrently determine rhynchophylline and hirsutine in rat plasma. The sample preparation of rat plasma was achieved by alkalization and liquid-liquid extraction. The mass transition of precursor ion → product ion pairs were monitored at m/z 385.2 → 160.0 for rhynchophylline, m/z 369.3 → 144.0 for hirsutine and m/z 414.0 → 220.0 for noscapine (internal standard). This method revealed linear relationships from 2.5 to 50 ng/mL (r(2) > 0.997) for rhynchophylline and from 2.5 to 50 ng/mL (r(2) > 0.998) for hirsutine. The limit of quantification values for rhynchophylline and hirsutine in rat plasma were both 2.5 ng/mL. Intra-day and inter-day precisions were within 10.6% and 12.5%, respectively, for rhynchophylline and hirsutine, and the accuracy (bias) was <10%. Liquid-liquid extraction of rat plasma samples resulted in insignificant matrix effect, and the extraction recoveries were >83.6% for rhynchophylline, 73.4% for hirsutine and 90.7% for the internal standard. This method was applied successfully to a pharmacokinetic study of rhynchophylline and hirsutine in rats after oral administration.

Determination of dimethyltryptamine and ß-carbolines (ayahuasca alkaloids) in plasma samples by LC-MS/MS.

BACKGROUND: Ayahuasca is a psychoactive plant beverage originally used by indigenous people throughout the Amazon Basin, long before its modern use by syncretic religious groups established in Brazil, the USA and European countries. The objective of this study was to develop a method for quantification of dimethyltryptamine and ß-carbolines in human plasma samples. RESULTS: The analytes were extracted by means of C18 cartridges and injected into LC-MS/MS, operated in positive ion mode and multiple reaction monitoring. The LOQs obtained for all analytes were below 0.5 ng/ml. By using the weighted least squares linear regression, the accuracy of the analytical method was improved at the lower end of the calibration curve (from 0.5 to 100 ng/ml; r(2)> 0.98). CONCLUSION: The method proved to be simple, rapid and useful to estimate administered doses for further pharmacological and toxicological investigations of ayahuasca exposure.

Simultaneous determination and pharmacokinetic analysis of seven alkaloids and two flavonoids from rat plasma by HPLC-DAD after oral administration of Wuzhuyu decoction.

A simple and sensitive high-performance liquid chromatographic method was developed for the simultaneous determination and pharmacokinetic analysis of seven alkaloids dehydroevodiamine (DHED), 10-hydroxyrutaecarpine (HDR), evodiamine (EDM), rutaecarpine (RCP), 1-methyl-2-n-nonyl-4(1H)quinolone (MNQ), evocarpine (ECP), and dihydroevocarpine (DHE), and two flavonoids isorhamnetin-7-O-rutinoside (RIM) and diosmetin-7-O-ß-d-glucopyranoside (GRD) in rat plasma after oral administration of Wuzhuyu decoction. The flow rate was kept at 1.0 ml/min and the detection wavelength was set at 300 nm. The calibration curves were linear in the range of 0.5013-30.076 µg/ml for DHED, 0.2161-21.608 µg/ml for RIM, 0.161-12.876 µg/ml for HDR, 0.2146-21.457 µg/ml for GRD, 2.0464-40.928 µg/ml for EDM, 1.0398-31.194 µg/ml for RCP, 0.5970-35.818 µg/ml for MNQ, 0.8371-20.928 µg/ml for ECP, and 0.5167-31.003 µg/ml for DHE. The precision (relative standard deviation (RSD), %) for all was less than 10% and the accuracy (relative error (RE), %) was within ± 10%. The results demonstrated that the assay had remarkable reproducibility with acceptable accuracy and precision. The lower limit of quantifications for the compounds in plasma ranged from 0.12 to 0.23 µg/ml and the lower limit of detections ranged from 0.024 to 0.076 µg/ml. This validated method has been successfully applied in the pharmacokinetics study of seven alkaloids and two flavonoids after orally administrating the Wuzhuyu decoction to rats.

Design and evaluation of a novel evodiamine-phospholipid complex for improved oral bioavailability.

A novel evodiamine (EVO)-phospholipid complex (EPLC) was designed to improve the bioavailability of EVO. A central composite design approach was employed for process optimization. EPLC were characterized by differential scanning calorimetry, ultraviolet spectroscopy, Fourier transformed infrared spectroscopy, (1)H-NMR spectroscopy, matrix-assisted laser desorption/ionization time-of-flight spectroscopy, apparent solubility, and dissolution rate. After oral administration of EPLC, the concentrations of EVO at different time points were determined by high-performance liquid chromatography. The optimal formulation for EPLC was obtained where the values of X (1), X (2), and X (3) were 2, 0.5, and 2.5 mg/mL, respectively. The average particle size and zeta potential of EPLC with the optimized formulation were 246.1 nm and -26.94 mV, respectively. The EVO and phospholipids in the EPLC were associated with non-covalent interactions. The solubility of EPLC in water and the dissolution rate of EPLC in phosphate-buffered solution (pH 6.8) were substantially enhanced. The plasma EVO concentration-time curves of EPLC and free EVO were both in accordance with the two-compartment model. The peak concentration and AUC(0-∞) of EPLC were increased, and the relative bioavailability was significantly increased to 218.82 % compared with that of EVO.

Pharmacokinetic comparisons of rutaecarpine and evodiamine after oral administration of Wu-Chu-Yu extracts with different purities to rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Wu-Chu-Yu is a well-known herbal drug used for hypertension. Rutaecarpine and evodiamine are main bioactive components of the medicine. MATERIALS AND METHODS: A sensitive and specific HPLC method was developed to analyze rutaecarpine (Rut) and evodiamine (Evo) in rat whole blood. The pharmacokinetics of Rut and Evo after oral administration of Wu-Chu-Yu extracts with different purities to rats was compared to evaluate the effect of purity of Wu-Chu-Yu extracts on the absorption of Rut and Evo. Male Sprague-Dawley rats were given Wu-Chu-Yu extracts with different purities (high, medium and low) approximately the same doses of equivalent to Rut (40 mg/kg) and Evo (31 mg/kg). The contents of Rut and Evo were 45 and 35%, 28 and 21%, 9 and 7% in high, medium and low purity extracts, respectively. At different time points (0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3 and 4h) after administration, the concentrations of Rut and Evo in rat whole blood were determined by HPLC, and main pharmacokinetic parameters were calculated. RESULTS: The results indicated that the absorption of Rut and Evo in Wu-Chu-Yu extracts was improved when compared with the pure Rut and Evo and there were significant differences among different groups. CONCLUSIONS: The bioavailability of Rut and Evo was increased along with the increasing of purity (16%-80%) in Wu-Chu-Yu extracts.

[Determination of evodiamine and rutaecarpine of compound Wuzhuyu cataplasm in plasma by SPE-HPLC: application to its pharmacokinetics].

OBJECTIVE: To establish a SPE-HPLC method for the determination and pharmacokinetic study of evodiamine and rutacarpine in rat plasma. METHOD: A Kromasil C18 column (4.6 mm x 250 mm, 5 microm) was used with acetonitrile-water-tetrahydrofuran-acetic acid (51:48:1:0.1) as a mobile phase and at a flow rate of 1 mL x min(-1), and the UV detection was at 225 nm. The column temperature was 35 degrees C. After the analytes were extracted from the plasma of rats by solid phase extraction (SPE), the content of evodiamine and rutaecarpine was measuared by HPLC method using halcinonide as an internal standard solution. RESULT: After transdermal administration to rats, the pharmacokinetic behavior of evodiamine and rutaecarpine belongs to the one-compartment model. The main pharmacokinetic parameters was as follows: K(a) 0.224 h(-1) and 0.220 h(-1), K(e) 0.114 h(-1) and 0.118 h(-1), C(max) 0.211 mg x L(-1) and 0.272 mg x L(-1), T(peak) 6.132 h and 6.102 h, respectively. CONCLUSION: The method in this study is simple, rapid and sensitive. It is proved to be suitable for pharmacokinetic study of evodiamine and rutaecarpine.

Determination of evodiamine and rutecarpine in human serum by liquid chromatography-tandem mass spectrometry.

Evodiamine and rutecarpine are two kinds of indole alkaloids contained in the fruit of Evodiae fructus, which have been shown to exhibit various bioactivities in humans. A liquid chromatography-tandem mass spectrometric method (LC-MS/MS) was developed for the determination of evodiamine and rutecarpine in human serum. The serum was extracted by solid-phase extraction (SPE) and analyzed using a C18 column and a mobile phase consisting of methanol-water (85:15) solution containing 5 mmol/L ammonium formate at a flow rate of 0.5 mL/min. The mass spectrometer was operated in positive mode, employing the extracted ion chromatogram (EIC) for detection and quantitation of evodiamine (m/z 288) and rutecarpine (m/z 304). Good linear relationships between the peak area and the concentration were obtained in the ranges of 5.2-1040 ng/mL and 10.2-1020 ng/mL, with correlation coefficients (r) of 0.999 and 0.998, for evodiamine and rutecarpine, respectively. The repeatabilities (RSD, n=6) of quantitation for evodiamine and rutecarpine were 2.18-4.00% and 2.99-5.67%, respectively, and the recovery ranged from 90.5% to 98.1%. A comparative study of the different ionization and quantitation modes, including ESI-MS, ESI-MS/MS, APCI-MS and APCI-MS/MS, was also accomplished. The MS/MS fragmentation mechanism of the base peak ([M+H](+), m/z 304) of evodiamine was investigated in order to identify the analytes in more complicated body fluid samples.