LC–HRMS determination of piperine on rat dried blood spots: A pharmacokinetic study

A liquid chromatography-high resolution mass spectrometry （LC-HRMS） method was developed and validated for the determination of piperine （PPR） on dried blood spots （DBS）. DBS samples were prepared by spiking the whole blood with analyte to produce 30 μL of blood spots on specimen collection cards. Chromatographic separation was achieved on an Atlantis dC18 column using acetonitrile and water （0.1% formic acid） （85：15, v/v） as mobile phase in an isocratic mode of elution at a flow rate of 0.75 mL/min. MS detection was carried out in electrospray positive ion mode for the target ions and monitored at m/z 286.1465 for PPR and 272.1303 for the internal standard （IS）. The developed method exhibited a linear dynamic range over 0.01-2000 ng/mL for PPR on DBS. The overall extraction recovery of PPR from DBS was 92.5%. Influence of hematocrit and spot volume on DBS was also evaluated and found to be well within the acceptable limits. The method was successfully applied to pharmacokinetic studies of PPR in rats.

Comparison of conventional and supported liquid extraction methods for the determination of sitagliptin and simvastatin in rat plasma by LC-ESI-MS/MS

Three extraction methods were compared for their efficiency to analyze sitagliptin and simvastatin in rat plasma by LC-MS/MS, including （1） liquid-liquid extraction （LLE）, （2） solid phase extraction （SPE） and （3） supported liquid extraction （SLE）. Comparison of recoveries of analytes with different extraction methods revealed that SLE was the best extraction method. The detection was facilitated with ion trap-mass spectrometer by multiple reactions monitoring （MRM） in a positive ion mode with ESI. The transitions monitored were m./z 441.1→325.2 for simvastatin, 408.2→235.1 for sitagliptin and 278.1→260.1 for the IS. The lower limit of quantification （LLOQ） was 0.2 ng/mL for sitagliptin and 0.1 ng/mL for simvastatin. The effective SLE offers enhanced chromatographic selectivity, thus facilitating the potential utility of the method for routine analysis of biological samples along with pharmacokinetic studies.

Direct injection HILIC-MS/MS analysis of darunavir in rat plasma applying supported liquid extraction

A novel bioanalytical method was developed and validated for the quantitative determination of darunavir（DRV） in rat plasma by employing hydrophilic interaction chromatography and tandem mass spectrometry（HILIC-MS/MS） with supported liquid extraction（SLE）.lrbesartan（IRB） was used as an internal standard（IS）.The analyte in rat plasma（200 μL） was isolated through SLE using ethyl acetate as the eluting solvent.The chromatographic separation was achieved on Luna-HILIC（250 mm × 4.6 mm,5 μm）column with a mobile phase of 0.1% of formic acid in water：acetonitrile（5：95,v/v）,at a constant flow rate of 1.0mL/min.The MS/MS ion transitions for DRV（548.1→392.0） and IS（429.2→207.1） were monitored on an ion trap mass spectrometer,operating in the multiple reaction monitoring（MRM） mode.The lower limit of quantitation（LLOQ） was 0.2 ng/mL and quantitation range was 0.2-5000 ng/mL.The method was validated for its selectivity,sensitivity,carryover,linearity,precision,accuracy,recovery,matrix effect and stability.The method was successfully applied to pharmacokinetic study in rats.

Development of a validated UPLC-qTOF-MS/MS method for determination of bioactive constituent from Glycyrrhiza glabra

An ultra-performance liquid chromatography quadrupole time of flight mass spectrometry （UPLC-qTOF-MS/MS） method was developed and validated for the simultaneous determination of glycyrrhizin and glycyrrhetic acid. These analytes were separated on a reverse phase C18 column using a mobile phase of acetonitrile：2% acetic acid in water （75：25, v/v） with a flow rate of 200 μL/min. The qTOF-MS was operated under multiple reaction monitoring （MRM） mode using the electrospray ionization （ESI） technique with positive ion polarity. A comparison of three different extraction techniques i.e. accelerated solvent extraction （ASE）, extraction under ultrasonic waves （USW） and the classical extraction by percolation （CE） method was done and quantification of these extracts was also carried out by the proposed method.

Further constituents from Rhododendron lepidotum L

A unusual flavone glycoside named Shamimarin(1) and a new compound Acetoxy-8-methyl-chromen-2H-one(2) were isolated from aerial parts of Rhododendron lepidotum L.along with four known coumarins daphnin(3),daphnetin 8-O-β-D-glucopyrano-side (4),daphnetin(5) and umbelliferone(6).The structural elucidations were based on analyses of chemical and spectroscopic data by including ID and 2D NMR analyses.

A Green Approach towards the Synthesis of Enantio Pure Diols Using Horse Radish Peroxidase Enzyme Immobilized on Magnetic Nanoparticles

Enantiopure epoxides and their corresponding chiral vicinal diols serve as valuable intermediates in the synthesis of biologically active pharma and agro-compounds and also value added fine chemicals. Biocatalysts are well known for their selective hydrolysis of racemic epoxides to give optically pure chiral diols. This study highlights an efficient process of synthesis of chiral vicinal diols in good yields and enantioselectiviy using horse radish peroxidase enzyme immobilized on the amine functionalized magnetic nano particles (Fe3O4 nanoparticles) as enzyme carriers. It also facilitates separation of MNP-immobilized enzymes by applying external magnetic field. The immobilization of magnetic nano particles was confirmed by transmission electron microscope (TEM) and scanning electron microscope (SEM). The MNP-immobilized peroxidase enzyme improved stability of the enzyme and has shown broader substrate specificity in enantioselective hydrolysis of racemic epoxides, under mild and environmentally friendly conditions. The methodology MNP-immobilized enzyme developed in the synthesis of chiral diols has a potential for use in large-scale applications.

Quantitative estimation of (-)-hinokinin, a trypanosomicidal marker in Piper cubeba, and some of its commercial formulations using HPLC-PDA

The fruits of Piper cubeba have been used in Ayurvedic system of medicine for pain,tastelessness, painful urination and mouth diseases. Among its various chemical constituents,（-）-hinokinin, a trypanosomicidal dibenzylbutyrolactone lignan, is found in significant quantities.For quality evaluation of P. cubeba fruit and its commercial formulations, there is an urgent need to develop an analytical method based on（-）-hinokinin. For this purpose, an HPLC method was developed using photo diode array detector and Waters HR C18 column with gradient elution consisting of water and acetonitrile. The developed method was validated as per ICH-Q2 B guidelines and found to be accurate, precise and linear over a wide range of concentrations（5–300 mg/m L）.（-）-Hinokinin contents were found to be in the range of 0.005–0.109%（m/m） in various P. cubeba samples. The developed method was extended to LC–MS for further identification and characterization of（-）-hinokinin in samples. The developed method is simple,rapid and specific, and can be used as a tool for quality control of P. cubeba fruits and its commercial formulations.

An unusual bioactive oleanane triterpenoid from Rhododendron campanulatum D.Don

不平常的 oleanane triterpene (1 ) 从杜鹃花属 campanulatum 的天线部分被孤立。混合物显示出突出的抗菌剂和 immunomodulatory 活动。混合物的结构被分光镜的数据包括 1D 和 2D NMR 决定光谱分析。