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ObjectiveTo establish a high performance liquid chromatography （HPLC） for simultaneous determination of baicalin magnesium and baicalein in rat plasma and tissues， and to investigate the effect of acute liver injury on pharmacokinetics and tissue distribution of baicalin magnesium in rats. MethodAcute liver injury rat model was induced by carbon tetrachloride （CCl4）. Normal rats and acute liver injury model rats were given an equal dose （287.31 mg·kg-1） of baicalin magnesium aqueous solution by intragastric administration， the orbital blood was collected at different time points， and HPLC was used to simultaneously determine the concentrations of baicalin magnesium and baicalein in rat plasma at each time point， the concentration-time curves were drawn， the pharmacokinetic parameters were calculated with DAS 3.0， and SPSS 23.0 was used for statistical analysis. After oral administration of baicalin magnesium aqueous solution， HPLC was used to simultaneously determine the contents of baicalin magnesium and baicalein in rat liver， lung， kidney， stomach， brain and small intestine at different time points， the mobile phase was 0.1% phosphoric acid aqueous solution-methanol， and the detection wavelength was 278 nm. ResultIn the acute liver injury model group， the peak concentration （Cmax） of baicalin magnesium was 0.58 times that of the normal group， the area under concentration-time curve （AUC0-t） was 0.5 times that of the normal group （P<0.05）， the apparent volume of distribution （Vd） was 2.3 times that of the normal group （P<0.05）， and baicalein is almost undetectable in plasma. The content of baicalin magnesium in liver， stomach and brain of the acute liver injury model group was higher than that of the normal group at each time point， while the content of baicalin magnesium in the samples of lung at 8 h， kidney at 8 h and 12 h， and small intestine at 0.333 h was lower than that of the normal group. The content of baicalein in lung， stomach and small intestine of the model group was higher than that of the normal group at each time point， while the content of baicalein in the tissue samples of liver at 6， 8 h and kidney at 0.333， 4， 6 h was lower than that in the normal group， and baicalein could hardly be detected in the brain. ConclusionAfter intragastric administration of the same dose of baicalin magnesium aqueous solution， acute liver injury induced by CCl4 can affect the pharmacokinetics and tissue distribution characteristics of baicalin magnesium in rats， and there is biotransformation of baicalin magnesium and baicalein in liver， lung， kidney， stomach and small intestine.
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AIM To investigate the effects of aqueous extraction at normal temperature,40 ℃,and water boiling on total coumarins extract of Angelicae dahuricae Radix.METHODS For the extracts Ⅰ-Ⅳ obtained by ethanol reflux extraction and three aqueous extraction preprocessing methods,respectively,UV and HPLC were adopted in the content determination of total coumarins and imperatorin,then the powder properties and dissolution rates were compared.RESULTS The contents of total coumarins in four extracts were 3.98％,6.03％,6.81％ and 4.46％,while those of imperatorin were 0.633％,0.540％,0.465％ and 0.155％,respectively.The angles of repose were 48.455°,42.587°,42.689° and 42.024° with the bulk densities of 0.214,0.324,0.316 and 0.354 g/cm3,respectively.Within 100 min,extract Ⅰ demonstrated higher moisture adsorption rate and equilibrium moisture absorption content than the other three extracts.The accumulative dissolution rates of various extracts were much higher than that of medicinal material fine powder within 120 min.CONCLUSION All the three aqueous extraction preprocessing methods can obviously improve the powder properties of total coumarins extract of A.dahuricae Radix and increase the dissolution rate of medicinal material fine powder.
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Objective To investigate the effect of particle size on the physicochemical properties, aqueous solubility and physical stability of diosgenin nanosuspensions (DSG-NS). Methods DSG-NS with different particle sizes were prepared using the milling bead with the diameter of 0.5 (DSG-NS0.5) and 1.0 mm (DSG-NS1.0) by media milling method using the combination of Pluronic F127 and sodium dodecyl sulfate as stabilizer, respectively. The DSG-NS were solidified by freeze drying method. The physicochemical properties of DSG-NS were characterized in term of particle distribution, scanning electron microscope, X-Ray diffraction and Fourier transform infrared spectroscopy. The aqueous solubility of DSG-NS with two particle size was compared by equilibrium solubility and dissolution rate. Results The particle sizes of the DSG-NS1.0 and DSG-NS0.5 prepared in this paper were (762.5 ± 18.4) and (342.8 ± 7.3) nm with the polydisperson index (PDI) of 0.435 ± 0.087 and 0.170 ± 0.018, respectively. The re-dispersed freeze drying products had particle sizes of (919.0 ± 27.2) and (458.0 ± 10.3) nm with the polydisperson index of 0.521 ± 0.094 and 0.298 ± 0.021, respectively. Both DSG-NS1.0 and DSG-NS0.5 had an irregular rod-shape or flake without any aggregates. The DSG retained its original crystalline state during the manufacturing process of DSG-NS1.0 and DSG-NS0.5. The solubilities of freeze drying DSG-NS1.0 and DSG-NS0.5 were (5.094 ± 2.083) and (26.121 ± 10.286) μg/mL. The accumulated dissolution rate of freeze drying DSG-NS1.0 and DSG-NS0.5 was 36.1% and 64.9% in 60 min, respectively. The particle size presented significant increase in 10 d for the DSG-NS1.0, whereas it had no change in 30 d for DSG-NS0.5. However, the particle size and distribution of the freeze drying DSG-NS1.0 and DSG-NS0.5 were stable during the storage of 3 month. Conclusion The reduction of particle size had no effect on the changing of morphology and original crystalline state and contributed to the improvement of solubility, dissolution rate and physical stability of DSG-NS.
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OBJECTIVE: To develop and validate a sensitive and specific ultra-performance liquid chromatography-tandemmass spectrometric (LC-MS/MS) method for the assay of diosgenin in rat plasma. METHODS: Tanshinone ⅡA was employed as internal standard. Diosgenin was determined after the methanol-mediated plasma protein precipitation. The separation was performed on the Phenomenex kinetex xb C18 column (2.1 mm×50 mm, 2.6 μm) gradiently eluted with the mobile phase consisting of methanol(containing 0.1% formic acid)-0.1% aqueous formic acid. The flow rate was 0.2 mL·min-1, the column temperature was maintained at 40℃, and the injection volume was 5 μL. A triple quadrupole mass spectrometer equipped with electrospray ionization source was used as detector in a positive ion mode. Multiple reaction monitoring (MRM) mode was applied with the transition of m/z 415.2→271.1 and m/z 295.1→249.1 for diosgenin and internal standard, respectively. RESULTS: For diosgenin the standard curve was linear from 10 to 500 ng·mL-1(r=0.998 3), the limit of quantitative limit was 10 ng·mL-1, the intra- and inter-assay variabilities were below 15%, the accuracies were between 96.1% and 102.3%, the average extract recoveries ranged from 73.8% to 75.2%, and the matrix effects was between 85.8% and 91.7%. For the internal standard, the extract recovery and matrix effects were 83.8% and 92.4%, respectively. The rats were administered orally with diosgenin (100 mg·kg-1). The peak concentration of diosgenin was (344.067±34.48) ng·mL-1, the time for peak concentration was (4.167±2.041) h, the half-time was (14.85±10.53) h, and the area under concentration-time curve from zero to 72 h was (4 965.648±1 036.129) μg·h·L-1. CONCLUSION: This assay is specific, simple, sensitive and rapid, which can be applied in the pharmacokinetic study of diosgenin in rats.