Yunli Zhao

Simultaneous determination of limonin, dictamnine, obacunone and fraxinellone in rat plasma by a validated UHPLC–MS/MS and its application to a pharmacokinetic study after oral administration of Cortex Dictamni extract

A rapid and selective ultra high performance liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of four major ingredients in Cortex Dictamni extract, including limonin, dictamnine, obacunone and fraxinellone in rats plasma. Nimodipine was used as the internal standard. Following extraction by methyl tert-butyl ether, the analytes were separated on a Thermo Syncronis C18 column by a gradient elution within a runtime of 9min. The mobile phase consisted of A (methanol) and B (2mmol/L ammonium acetate in water). The detection was accomplished by using positive ion electrospray ionization in multiple reaction monitoring mode. The method was linear for all analytes over investigated range with all correlation coefficients greater than 0.998. The lower limits of quantification were 9.18ng/mL for limonin, 12.0ng/mL for dictamnine, 16.05ng/mL for obacunone and 4.59ng/mL for fraxinellone. The intra- and inter-day precision (RSD%) was within 10% and the accuracy (RE%) ranged from -12.9% to 9.7%. This rapid and sensitive method was fully validated and successfully applied to the pharmacokinetic study of limonin, dictamnine, obacunone and fraxinellone in the rat plasma after oral administration of Cortex Dictamni extract.

Pharmacokinetics and tissue distribution of docetaxel by liquid chromatography-mass spectrometry: evaluation of folate receptor-targeting amphiphilic copolymer modified nanostructured lipid carrier.

A novel amphiphilic copolymer, folate-poly(PEG-cyanoacrylate-co-cholesteryl cyanoacrylate) (FA-PEG-PCHL) was synthesized to modify docetaxel-loaded nanostructured lipid carrier to lead to a long blood circulating effect and targeting ability for the delivery of antitumor drug in cancer. To investigate the characteristics of modified docetaxel-loaded nanostructured lipid carrier in vivo, a liquid chromatography-mass spectrometry method was developed and validated for the determination of docetaxel in rat plasma and tumor-bearing mouse tissue samples. The biosamples were extracted by liquid-liquid extraction method with ether and separated on a C(18) column (150 mm×4.6 mm, 5 μm) using a mobile phase consisting of methanol-0.01% formic acid water (82:18, v/v). The standard curves were linear over the ranges of 0.01-4.0 μg/mL for plasma and 0.02-8.0 μg/g for tissue samples, respectively. The validated method was successfully applied to the pharmacokinetic study in rat plasma and tissue distribution study in mouse tissues of docetaxel after an intravenous administration of docetaxel injection (DTX injection), docetaxel-loaded nanostructured lipid carrier (DTX-NLC) and FA-PEG-PCHL-modified docetaxel-loaded nanostructured lipid carrier (FA-DTX-NLC), respectively. The results indicated that the FA-DTX-NLC led to significant differences in pharmacokinetic profile and tissue distribution. Nanostructured lipid carrier modified by FA-PEG-PCHL could be one of the promising suspensions for the delivery of docetaxel in cancer.

Pharmacokinetics, tissue distribution and excretion study of dictamnine, a major bioactive component from the root bark of Dictamnus dasycarpus Turcz. (Rutaceae).

Dictamnine is an herbal ingredient isolated from the root bark of Dictamnus dasycarpus Turcz. (Rutaceae). The present study was aimed at the development of an ultra-high performance liquid chromatography-tandem mass spectrometry method to quantify the concentration of dictamnine in rat plasma and tissues for the in vivo pharmacokinetics, tissue distribution and excretion study. Biological samples were processed with protein precipitation. Skimmianine was chosen as internal standard. The chromatographic separation was carried out on a Thermo Syncronis C18 column (2.1mm×50mm, 1.7μm) with an isocratic mobile phase consisting of methanol and 0.1% formic acid water (75:25, v/v). The detection was accomplished by using positive ion electrospray ionization in multiple reaction monitoring (MRM) mode. The MS/MS ion transitions were monitored at m/z 200.0→129.0 for dictamnine and 260.3→227.1 for IS, respectively. An excellent linearity was observed over the concentration range from 0.5 to 250ng/mL. The lower limit of quantification (LLOQ) was 0.5ng/mL for dictamnine. The developed method was rapid, accurate, and highly sensitive and selective. It was successfully applied to the in vivo pharmacokinetics, tissue distribution and excretion study of dictamnine in rats after oral or intravenous administration of dictamnine.

A fast, sensitive, and high throughput method for the determination of cefuroxime lysine in dog plasma by UPLC-MS/MS.

In order to investigate the preclinical pharmacokinetics of cefuroxime lysine, a fast, sensitive and high throughput UPLC-ESI-MS/MS method has been developed and validated for the quantitative determination of cefuroxime in dog plasma. Cefuroxime and IS phenacetin were extracted from plasma samples by PPT or LLE procedure, and then separated on an ACQUITY UPLC™ BEH C(18) column with an isocratic elution of acetonitrile-0.1% formic acid in 10mM ammonium acetate (40:60, v/v). MRM using the fragmentation transitions of m/z 442 → 364 and 180 → 110 in positive ESI mode was performed to quantify cefuroxime and IS, respectively. The calibration curves were linear over the concentration range of 2-400 μg/ml for PPT and 0.01-5 μg/ml for LLE. The LLOQ was 0.01 μg/ml. The intra- and inter-day precisions in all samples were no more than 8.1%, while the accuracy was within ± 6.2% of nominal values. The method was successfully applied to the evaluation of pharmacokinetic parameters of cefuroxime lysine in beagle dogs.

Simultaneous determination of cinnamaldehyde, cinnamic acid, and 2-methoxy cinnamic acid in rat whole blood after oral administration of volatile oil of Cinnamoni Ramulus by UHPLC-MS/MS: An application for a pharmacokinetic study

A simple and rapid ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the simultaneous determination of cinnamaldehyde, cinnamic acid, and 2-methoxy cinnamic acid in rat whole blood. It was the first time to study the pharmacokinetics of 2-methoxy cinnamic acid in rat whole blood. Samples were processed by a one-step protein precipitation with acetonitrile-37% formaldehyde (90:10, v:v). Chromatographic separation was performed on a Thermo Scientific C18 column (2.1mm×50mm, 1.9μm) at room temperature. The total run time was 4min. The detection was accomplished by using positive and negative ion electrospray ionization in multiple reaction monitoring mode. The method was linear for all of the analytes over 1000 times concentration range with correlation coefficients greater than 0.99. The lower limits of quantification (LLOQ) were 0.1ng/mL for cinnamaldehyde, 5.8ng/mL for cinnamic acid, and 10ng/mL for 2-methoxy cinnamic acid, respectively. To our knowledge, this was the first time that the LLOQ for cinnamaldehyde in validated methods for biological samples was as low as 0.1ng/mL. Intra- and inter-day precision and accuracy were within ±9% for all of the analytes during the assay validation. Assay recoveries were higher than 80% and the matrix effects were minimal. The half-life were 8.7±0.7h for cinnamaldehyde, 1.0±0.5h for cinnamic acid, and 1.4±0.4h for 2-methoxy cinnamic acid, respectively. The validated assay was firstly applied to the simultaneous quantification of cinnamaldehyde, cinnamic acid, and 2-methoxy cinnamic acid, especially for 2-methoxy cinnamic acid in rat whole blood after oral administration of 15mg/kg essential oil of Cinnamoni Ramulus. It was observed that the Cmax and AUC of 2-methoxy cinnamic acid (0.01% in essential oil of Cinnamoni Ramulus) were greater than those of cinnamaldehyde (83.49% in essential oil of Cinnamoni Ramulus), which implied that 2-methoxy cinnamic acid might be the major bioactive constitutes in essential oil of Cinnamoni Ramulus.

Secondary Metabolites of the Marine Fungus Penicillium chrysogenum

A new benzoic acid, 2-(2-hydroxypropanamido) benzoic acid (1), along with three known compounds, cyclo-(Pro-Leu), cyclo-(4-hydroxyl-Pro-Phe), and (22E,24R)-ergosta-5,7,22-triene-3β-ol, were isolated from the fermentation broth of Penicillium chrysogenum. The structure of compound 1 was established by comprehensive analysis of the spectral data, especially 2D NMR spectra. Compound 1 showed remarkable anti-inflammatory and analgesic activities when administered at 100 mg/kg, but it exhibited no ulcerogenic effect.

Metabolism of dictamnine in liver microsomes from mouse, rat, dog, monkey, and human

Dictamnine, a furoquinoline alkaloid isolated from the root bark of Dictamnus dasycarpus Turcz. (Rutaceae), is reported to have a wide range of pharmacological activities. In this study, the in vitro metabolic profiles of dictamnine in mouse, rat, dog, monkey, and human liver microsomes were investigated and compared. Dictamnine was incubated with liver microsomes in the presence of an NADPH-regenerating system, resulting in the formation of eight metabolites (M1-M8). M1 is an O-desmethyl metabolite. M5 and M6 are formed by a mono-hydroxylation of the benzene ring of dictamnine. M8 was tentatively identified as an N-oxide metabolite. The predominant metabolic pathway of dictamnine occurs through the epoxidation of the 2,3-olefinic to yield a 2,3-epoxide metabolite (M7), followed by the ring of the epoxide opening to give M4. Likewise, cleavage of the furan ring forms M2 and M3. Slight differences were observed in the in vitro metabolic profiles of dictamnine among the five species tested. A chemical inhibition study with a broad and five specific CYP450 inhibitors revealed that most of the dictamnine metabolites in liver microsomes are mediated by CYP450, with CYP3A4 as the predominant enzyme involved in the formation of M7, the major metabolite. These findings provide vital information to better understand the metabolic processes of dictamnine among various species.

Simultaneous qualitative and quantitative analysis of 21 mycotoxins in Radix Paeoniae Alba by ultra-high performance liquid chromatography quadrupole linear ion trap mass spectrometry and QuEChERS for sample preparation

A high-throughput method for simultaneous qualitative and quantitative analysis of 21 mycotoxins in Radix Paeoniae Alba (RPA) was developed by coupling the modified QuEChERS method with ultra-high performance liquid chromatography quadrupole linear ion trap mass spectrometry (UHPLC-QqLIT-MS). The 21 mycotoxins were extracted and cleaned up using QuEChERS-based procedure, then further separated on a C18 column and detected by a hybrid triple quadrupole linear ion trap mass spectrometer equipped with electrospray ionization source in the multiple reaction monitoring-information dependent acquisition-enhanced product ion (MRM-IDA-EPI) mode. Under this technique, 13 mycotoxins were detected using acetonitrile and water containing 0.1% formic acid as the mobile phase in positive mode while the other 8 mycotoxins were detected using acetonitrile and water containing 0.1% ammonia as the mobile phase in negative mode. The calibration curves of all analytes showed good linearity (r(2)>0.995) within test ranges. The limits of detection and quantification ranged from 0.031 to 5.4μg/kg and 0.20 to 22μg/kg, respectively. Additionally, recoveries were all above 75.3% with relative standard deviations within 15%. The method proposed herein with significant advantages including simple pretreatment, rapid determination as well as high sensitivity, accuracy and throughput would be a preferred candidate for the determination and quantification of multi-class mycotoxin contaminants in real samples.

Metabolic profile of 2-(2-hydroxypropanamido) benzoic acid in rats by ultra high performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry

An ultra high performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry (UHPLC-FT-ICR-MS) method was developed to investigate the in vivo metabolism of 2-(2-hydroxypropanamido) benzoic acid (HPABA), a marine-derived anti-inflammatory drug, for the first time. Plasma, urine, feces and bile samples were collected from male and female rats after a single intragastric administration of HPABA at a dose of 100mg/kg. Besides the parent drug, a total of 13 metabolites (3 phase I and 10 phase II metabolites) were detected and tentatively identified through comparing their mass spectrometry profiles with those of HPABA. Results demonstrated that metabolic pathways of HPABA in rats included decarboxylation, hydroxylation, dehydrogenation, glucuronidation, glycine conjugation and N-acetyl conjugation. In summary, this work provided valuable information regarding the metabolism of HPABA in rats, which would contribute to better understanding of its safety and mechanism of action.

Detection and Chemical Profiling of Ling-Gui-Zhu-Gan Decoction by Ultra Performance Liquid Chromatography-Hybrid Linear Ion Trap-Orbitrap Mass Spectrometry

Ling-Gui-Zhu-Gan decoction (LGZGD), a well-known traditional Chinese medicine (TCM) formula, has been extensively used for the treatment of cardiovascular disease in clinic. However, the chemical constituents in LGZGD had not been investigated so far. In this study, an ultra performance liquid chromatography-hybrid electrospray ionization linear ion trap-Orbitrap mass spectrometry (UPLC-LTQ-Oribitrap-MS/MS) method was established for rapid separation and structural identification of the constituents in LGZGD. Separation was performed on an ACQUITY(TM) UPLC BEH C18 column (50 × 2.1 mm, 1.7 μm) by gradient elution mode, using acetonitrile-water containing 0.1% formic acid as mobile phase at the flow rate of 0.2 mL/min. Accurate mass measurement for molecular ions and characteristic fragment ions could represent identification criteria for these compounds. As a result, 95 compounds including triterpene acids, triterpene saponins, flavonoids, coumarins, coumestans, benzofurans, phenylpropanoids and sesquiterpenoid lactones were detected, and 90 of them were tentatively identified. All compounds were further assigned in the individual raw material. In conclusion, the UPLC-LTQ-Orbitrap-MS/MS is a highly efficient technique to separate and identify constituents in complex matrices of TCMs. These results obtained in this research will provide a basis for quality control and further in vivo study of LGZGD.