LC-MS/MS determination and pharmacokinetic study of dehydrocorydaline in rat plasma after oral administration of dehydrocorydaline and Corydalis yanhusuo extract.

A rapid, sensitive and selective liquid chromatography/tandem mass spectrometry method (LC-MS/MS) was developed and validated for determination of dehydrocorydaline (DHC) in rat plasma using nitidine chloride as an internal standard. The analytes were solid-phase extracted and eluted on a C18 chromatography column using a mobile phase of acetonitrile and water (containing 0.8% formic acid and 10 mM ammonium acetate) (28:72, v/v). Detection was performed using positive ion electrospray ionization in multiple reaction monitoring modes. The assay was linear over the concentration range 0.625-250 ng/mL with a quantification limit of 0.625 ng/mL. The precision was <13.7%, the accuracy >93.1%, and extraction recovery ranged from 92.1% to 107%. The validated method was successfully applied to the pharmacokinetics and excretion study of DHC in rat plasma after oral administration of pure DHC and an effective fraction of Corydalis yanhusuo (EFY). The pharmacokinetic parameters showed that DHC from EFY was absorbed more rapidly and eliminated more slowly than pure DHC. The result suggests that the differences might be due to the presence of P-glycoprotein (P-gp) inhibitors and that other alkaloids co-existing in the EFY may compete with DHC for transportation by P-gp, metabolization by P450, and binding to plasma proteins.

[Identification of foliumn pyrrosiae from different habitats and species by HPLC fingerprint].

OBJECTIVE: To establish HPLC fingerprint of Folium Pyrrosiae for identification. METHODS: The HPLC method was developed with Diamonsil C18 column (250 mm x 4.6 mm, 5 microm),and a mixture liquid of acetonitrile-0.8% acetic acid solution as mobile phase in a gradient elution. HPLC fingerprints of44 samples were analyzed by similarity, cluster and principal component analysis. RESULTS: The HPLC fingerprint common pattern of Pyrrosia petiolosa, Pyrrosia lingua and common pattern of Pyrrosia sheareri were set up separately. Samples from different species were classified based on the result of cluster and principal component analysis. Fingerprints of Pyrrosia sheareri and Pyrrosia lingua have high degree of similarity, but were different from Pyrrosia petiolosa, while Pyrrosia calvata and Pyrrosia assimlis were classified as adulterants with their dissimilar fingerprints. CONCLUSION: The method is stable and reliable with a good reproducibility and provides a reference standard for identifying Folium Pyrrosiae from different habitats and species.

[Identification and analysis of absorbed components in rat plasma after oral administration of active fraction of Corydalis yanhusuo by LC-MS/MS].

To analyze and identify the constituents in rat plasma after oral administration of the active fraction of Corydalis yanhusuo, a LC-MS/MS method was established. The constituents absorbed into blood, their original crude drugs and their metabolites were identified either by comparing the retention time and mass spectrometry data with that of reference compounds or by mass spectrometry analysis and retrieving the reference literatures. Nine species are the original form in Corydalis yanhusuo, moreover, some metabolites in blood identified as glucuronide were found. The constituents absorbed into blood and the possible metabolites which demonstrate to originate from the active fraction of Corydalis yanhusuo are responsible for the observed efficacy. Its serum pharmacochemistry should be subjected to complete investigation so as to illuminate the pharmacology and active mechanism of the active fraction of Corydalis yanhusuo.

The pharmacokinetic and pharmacodynamic properties of site-specific pegylated genetically modified recombinant human interleukin-11 in normal and thrombocytopenic monkeys.

In order to improve the pharmacokinetic and pharmacodynamic properties of recombinant human interleukin-11 mutein (mIL-11) and to reduce the frequency of administration, we examined the feasibility of chemical modification of mIL-11 by methoxy polyethylene glycol succinimidyl carbonate (mPEG-SC). PEG-mIL-11 was prepared by a pH controlled amine specific method. Bioactivity of the protein was determined in a IL-11-dependent in vitro bioassay, its pharmacodynamic and pharmacokinetic properties were investigated by using normal and thrombocytopenic monkey models. N-terminus sequencing and peptide mapping analysis revealed that Lys33 is the PEGylated position for PEG-mIL-11. Bioactivity of PEG-mIL-11 assessed by B9-11 cell proliferation assay was comparable to that of mIL-11. More than 79-fold increase in area-under-the curve (AUC) and 26-fold increase in maximum plasma concentration (Cmax) was observed in pharmacokinetic analysis. Single dose administration of the PEG-mIL-11 induced blood platelets number increase and the effect duration were comparable to that of 7 to 10 consecutive daily administration of mIL-11 to the normal and thrombocytopenic monkey models. PEG-mIL-11 is a promising therapeutic for thrombocytopenia.

LC-MS/MS method for determination of geldanamycin derivative GM-AMPL in rat plasma to support preclinical development.

A LC-MS/MS method for determining the concentration of the small molecule Hsp90 inhibitor, GM-AMPL, has been developed and validated in rat plasma to support preclinical development. 17-[2-(morpholine-4-yl)ethyl]amino-17-demethoxygeldanamycin (GM-AMPL) and the internal standard 17-allylamino-17-demethoxygeldanamycin (17-AAG) were sufficiently separated on a Venusil MP C18 column that was eluted with 80% methanol in water at 40°C. Quantification studies were performed with a multiple reaction monitoring (MRM) transition of m/z 657.3→614.3 and 584.3→541.3 for GM-AMPL and IS, respectively, in the negative ion mode. The present method exhibited good linearity (R>0.999) over the concentration range of 2-600ng/mL for GM-AMPL in rat plasma with a lower limit of quantification (LLOQ) of 2ng/mL. The intra-batch and inter-batch assay coefficients of variation (CV) were in range of 1.56-6.84% and 1.62-6.98%, respectively. The plasma samples were extracted with methanol to precipitate protein with extraction recovery in range of 84.09-95.25%. The matrix effect was determined as internal substance (IS) normalized matrix factor of 1.09, 1.18 and 1.05 for samples with three concentration levels of 4, 40 and 400ng/mL, respectively. This validated method was further applied to successfully determine the pharmacokinetic parameters and oral availability of GM-AMPL in Sprague-Dawley rats following intravenous injection and oral administration.