Jian Ni

Simultaneous determination and pharmacokinetic study of polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII in beagle dog plasma after oral administration of Rhizoma Paridis extracts by LC-MS-MS.

For the first time, a rapid and specific LC-MS-MS method has been developed for the analysis of polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII in beagle dog plasma. The method was applied to study the pharmacokinetics of Rhizoma Paridis extracts containing polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII. The analysis was carried out on an Agilent Zorbax XDB-C(18) reversed-phase column (100 × 2.1 mm, 1.8 µm) by isocratic elution with acetonitrile and water (50:50, v/v). The flow rate was 0.25 mL/min. All analytes including internal standards were monitored by selected reaction monitoring with an electrospray ionization source. Linear responses were obtained for polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII ranging from 10 to 5000 ng/mL. The intra-and inter-day precisions (RSDs) were less than 6.66 and 9.15%. The extraction recovery ranged from 95.53 to 104.21% with RSD less than 8.69%. Stability studies showed that polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII were stable in preparation and analytical process. The validated method was successfully used to determine the concentration-time profiles of polyphyllin I, polyphyllin II, polyphyllin VI and polyphyllin VII.

Preparation and evaluation of solid dispersions of a new antitumor compound based on early-stage preparation discovery concept.

Ensuring sufficient drug solubility is a crucial problem in pharmaceutical-related research. For water-insoluble drugs, various formulation approaches are employed to enhance the solubility and bioavailability of lead compounds. The goal of this study was to enhance the dissolution and absorption of a new antitumor lead compound, T-OA. Early-stage preparation discovery concept was employed in this study. Based on this concept, a solid dispersion system was chosen as the method of improving drug solubility and bioavailability. Solid dispersions of T-OA in polyvinylpyrrolidone (PVP) K30 were prepared by the solvent evaporation method. Dissolution testing determined that the ideal drug-to-PVP ratio was 1:5. X-ray diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry were employed to confirm the formation of solid dispersions. Scanning electron microscopy demonstrated that T-OA was converted into an amorphous form. Both in vitro dissolution testing and the in vivo studies demonstrated that the solubility and bioavailability of T-OA were significantly improved when formulated in a solid dispersion with PVP. The dissolution rate of the T-OA/PVP solid dispersion was greatly enhanced relative to the pure drug, and the relative bioavailability of T-OA solid dispersions was found to be 392.0%, which is 4-fold higher than the pure drug.

In-vitro and in-vivo comparison of T-OA microemulsions and solid dispersions based on EPDC

Abstract The goal of this study was to enhance the absorption of a new water-insoluble antitumor lead compound, T-OA (3β-hydroxyolea-12-en-28-oic acid-3, 5, 6-trimethylpyrazin-2-methyl ester). Early-stage preparation discovery concept (EPDC) was employed in this study. Based on this concept, a microemulsion system was chosen as the method of improving bioavailability. The solubility of T-OA was checked in different oils, surfactants and cosurfactants. Ternary phase diagrams were constructed to evaluate the microemulsion domain. Developed high-performance liquid chromatography method was used to determine drug content. The transparent o/w microemulsion formulation composed of oleic acid (oil), Tween 80 (surfactant), ethanol (co-surfactant) and water enhanced the solubility of T-OA up to 20u2009mg/mL. It was characterized in terms of appearance, content, viscosity, zeta potential, conductivity, morphology and particle size. The particle size distribution, viscosity, conductivity and zeta potential were found to be 70u2009nm, 15.57u2009MPau2009s, 44.1u2009μSu2009cm−1 and −0.174, respectively. Oral bioavailability of T-OA microemulsion and oleic acid solution were checked by using rat model. Contrast to the solid dispersion and proto drug, the area-under-the-curve (AUC) of T-OA microemulsion and oleic acid solution were significantly enhanced. The relative bioavailability of T-OA microemulsion was found to be 5654.7%, which is 57-fold higher than the pure drug. Improved T-OA solubility in microemulsion was found sustained 48u2009h in dilution study. While the solid dispersion may precipitate under the gastrointestinal circumstance based on dilution results. The in-vivo and in-vitro results indicated that, compare to improve the solubility, it is more important to maintain and prolong the T-OA dissolved status, for improvement of the in-vivo absorption.

Simultaneous analysis of polygala acid, senegenin and 3,6'-disinapoylsucrose in rat plasma by liquid chromatography-tandem mass spectrometry: application to a pharmacokinetic study after oral administration.

A rapid and specific LC-MS/MS method has been developed for the simultaneous analysis of polygala acid, senegenin and 3,6-disinapoylsucrose (DSS) in rat plasma. The method was applied to the pharmacokinetics studies of polygala acid, senegenin and DSS. The analysis was carried out on an Agilent Eclipse plus C18 reversed-phase column (100u2009×u20094.6 mm, 3.5 µm) by gradient elution with methanol and ammonia (0.01%, v/v). The flow rate was 0.4 mL/min. All analytes including internal standard (IS) were monitored by selected reaction monitoring with an electrospray ionization source. Linear responses were obtained for polygala acid and DSS ranging from 2.5 to 2000 ng/mL, and senegenin ranging from 5 to 2000 ng/mL. The intra- and inter-day precisions (relative standard deviation) were <11.34 and 8.99%. The extraction recovery ranged from 70.89u2009±u20094.60 to 88.49u2009±u20093.26%, and that for the IS was 77.23u2009±u20093.68%. Stability studies showed that polygala acid, senegenin and DSS are stable during the preparation and analytical process. The validated method was successfully used to determine the concentration-time profiles of polygala acid, senegenin and DSS.

Development and validation of a highly sensitive LC-ESI-MS/MS method for the determination of hyperoside in beagle dog plasma: application to a pharmacokinetic study.

A highly sensitive, rapid assay method has been developed and validated for the analysis of hyperoside in beagle dog plasma with liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. The assay procedure involves extraction of hyperoside and ginsenoside Re (IS) from beagle dog plasma. Chromatographic separation was carried out on an Agilent Zorbax XDB-C18 (100 × 2.1 mm, 1.8 µm) column by isocratic elution with acetonitrile and water (50:50, v/v) at a flow rate of 0.25 mL/min with a total run time of 2.0 min. The MS/MS ion transitions monitored were 464.4 → 463.4 for hyperoside and 947.12 → 969.60 for IS. Linear responses were obtained for hyperoside ranging from 10 to 5000 ng/mL. The intra-and inter-day precisions (RSDs) were <5.38 and 3.39% and the extraction recovery ranged from 94.39 to 100.78% with an RSD <3.82%. Stability studies showed that hyperoside was stable in preparation and analytical process. The results indicated that the validated method was successfully used to determine the concentration-time profiles of hyperoside.

Simultaneous Determination of Typhaneoside and Isorhamnetin-3-O-Neohesperidoside in Rats After Oral Administration of Pollen Typhae Extract by UPLC–MS/MS

For the first time, a selective and rapid ultra-performance liquid chromatography method with tandem mass spectrometric (UPLC-MS/MS) detection for simultaneous determination of typhaneoside and isorhamnetin-3-O-neohesperidoside in rat plasma was developed and validated, which was applied to the pharmacokinetic study of Pollen Typhae extract. The separation was carried out on an ACQUITY UPLC(TM) BEH C18 column with gradient elution using mobile phase including acetonitrile and water (containing 0.1% formic acid). The flow rate was 0.4 mL/min. The detection was conducted by means of electrospray ionization mass spectrometry in negative ion mode with multiple reaction monitoring. The assays were linear over the concentration range of 0.5-100 ng/mL, and the lower limit of quantification was 0.5 ng/mL for typhaneoside and isorhamnetin-3-O-neohesperidoside. The method was validated in terms of intra- and interday precision (<9.37%), accuracy (within ±10.91%), linearity, specificity and stability, and has been successfully applied to a pharmacokinetic study of Pollen Typhae extract in rats after oral administration.

Alterations of Amino Acid Level in Depressed Rat Brain

Amino-acid neurotransmitter system dysfunction plays a major role in the pathophysiology of depression. Several studies have demonstrated the potential of amino acids as a source of neuro-specific biomarkers could be used in future diagnosis of depression. Only partial amino acids such as glycine and asparagine were determined from certain parts of rats brain included hippocampi and cerebral cortex in previous studies. However, according to systematic biology, amino acids in different area of brain are interacted and interrelated. Hence, the determination of 34 amino acids through entire rats brain was conducted in this study in order to demonstrate more possibilities for biomarkers of depression by discovering other potential amino acids in more areas of rats brain. As a result, 4 amino acids (L-aspartic acid, L-glutamine, taurine and γ-amino-n-butyric acid) among 34 were typically identified as potentially primary biomarkers of depression by data statistics. Meanwhile, an antidepressant called Fluoxetine was employed to verify other potential amino acids which were not identified by data statistics. Eventually, we found L-α-amino-adipic acid could also become a new potentially secondary biomarker of depression after drug validation. In conclusion, we suggested that L-aspartic acid, L-glutamine, taurine, γ-amino-n-butyric acid and L-α-amino-adipic acid might become potential biomarkers for future diagnosis of depression and development of antidepressant.

Altered plasma and brain disposition of isopropylidene shikimic acid liposome in rats and the brain protection in cerebral ischemia–reperfusion

Context: Cerebral ischemia–reperfusion (I/R) injury is a secondary injury caused by oxidative stresses and inflammatory responses after recovery from cerebral ischemia. Brain protective drugs were used to reduce the injury. In order to improve the distribution in brain and enhance the brain-protective efficacy, some pharmaceutical technologies were used to achieve brain targeting delivery. Objective: To investigate the physiological disposition of ISA liposome, and provide references for the further study about high-efficacy brain-protective preparations for I/R injury. Materials and methods: Comparative studies were carried out. The pharmacodynamics in t-MCAO model rats were studied first, and then the pharmacokinetics and brain distribution of the two preparations were determined. Results: At the same dose, the efficacy of ISA liposome was better (P < 0.05). The efficacy was dose dependent, with significant difference of 20u2009mg/kg (P < 0.01) and indistinctive difference of 10u2009mg/kg (P = 0.22), compared with vehicle-treated rats. The parameters, T1/2β, MRT and AUC were different significantly between the two preparations. The enhancement of brain distribution for ISA in the liposome was obvious, with the maximum concentration 7.18 μg/g, while close to zero for the solution group. Discussion and conclusion: ISA liposome could increase the distribution in brain and enhance the efficacy significantly. The results revealed that the liposomal DDS was potential as a novel strategy for the treatment of cerebral I/R injury. In addition, further targeted modification, such as PEG-modified liposomes, which possess a long circulating property in the bloodstream, would further improve the targeting delivery to the brain and lead to more significant efficacy.

Simultaneous LC-MS/MS quantification and pharmacokinetics of baicalin, chlorogenic acid and forsythin after intravenous administration of Shuang-huang-lian powder to dogs

A sensitive and specific high-performance liquid chromatography-tandem mass method (LC-MS/MS) has been developed and validated for the simultaneous determination of baicalin, chlorogenic acid and forsythin in dog plasma using a chemical synthetic compound buspirone as the internal standard (IS). Chromatographic separation was accomplished on a Phenomenex Gemini C18 column (2.0 × 50 mm, I.D., 3.5 μm) with a gradient elution system composed of 0.1% formic acid in water and 0.1% formic acid in methanol at a flow rate of 0.40 mL min−1. Detection was based on a triple quadrupole mass spectrometer using a multiple reaction monitoring (MRM) mode with an electrospray ionization source (ESI). The precursor/product transitions (m/z) in the positive ion mode were 447.3 → 271.1, 355.3 → 163.3, 556.9 → 309.3, and 386.5 → 122.1 for baicalin, chlorogenic acid, forsythin and IS, respectively. All of the calibration curves showed good linearity (r > 0.995) over the concentration range of 1.0 to 1000 ng mL−1 and the lower limits of quantification (LLOQs) were all 1.0 ng mL−1 for three analytes. The intra-day and inter-day precisions (% RSD) of low-level QC samples were all less than 20% and the precisions (% RSD) of high- and medium-level were all less than 15%. The accuracies at three QC levels ranged from 80 to 120%. The mean recoveries were all above 80% for three analytes. All the three analytes in dog plasma were stable at three different conditions. The well-established and fully validated method was firstly applied to the pharmacokinetics of baicalin, chlorogenic acid and forsythin in dogs after intravenous administration of Shuang-huang-lian freeze-dried powder. Significant double and/or multiple-peak phenomena in plasma concentration–time profiles of three analytes were observed in all six dogs, which are thought to be the results of the enterohepatic cycle.

Simultaneous determination and pharmacokinetic study of polygalaxanthone III, tenuifolin, tenuifoliside A and tenuifoliside C in rat plasma by LC-MS/MS after oral administration

For the first time, a rapid and specific LC-MS/MS method has been developed for the simultaneous analysis of polygalaxanthone III, tenuifolin, tenuifoliside A and tenuifoliside C in rat plasma, and was applied to the pharmacokinetics (PK) studies of those three compounds. The analysis was carried out on an Agilent Eclipse plus C18 reversed-phase column (100 × 4.6 mm, 3.5 μm) by gradient elution with methanol and ammonia (0.01%, v/v). The flow rate was 0.4 mL min−1. All analytes including internal standards (I.S.) were monitored by selected reaction monitoring with an electrospray ionization source. Linear responses were obtained for polygalaxanthone III and tenuifoliside A ranging from 1 to 2000 ng mL−1, and tenuifolin and tenuifoliside C ranging from 2.5 to 2000 ng mL−1. The intra-day and inter-day precisions (RSD) were less than 12.98% and 7.50% respectively. The extraction recovery ranged from 70.06 ± 6.33% to 86.95 ± 5.35%, and I.S. was 77.23 ± 3.68%. Stability studies showed that the accuracies of polygalaxanthone III, tenuifolin, tenuifoliside A and tenuifoliside C ranged from 93.18% to 106.70%. The matrix effects ranged from 91.72 ± 4.80 to 101.84 ± 5.04. The validated method was successfully used to determine the concentration–time profiles of polygalaxanthone III, tenuifolin, tenuifoliside A and tenuifoliside C.