Dihydrotestosterone Bayberry The Flavin Phospholipid Complexes And Solid Dispersions

Dihydromyricetin, a kind of natural flavonoid in "Yao zu teng cha",which has many pharmacological activities, including hypoglycemic, liver-protecting, hypotensive, antitussive, dispelling phlegm, rejecting lipid peroxidation and so on, has wide prospect in application. The clinical applications were limited because its bad water solubility, hydrophilicity and lipophilicity. Phospholipid complex was prepared to improve the affinity for cellular membrane and oral absorption and its bioavailability; Solid dispersion was also prepared to accelerate the dissolution speed and rate by using solvent evaporation method with PVPK₃₀ as the carrier, In this pater, the isolation and purification of dihydromyricetin, the preparation of phospholipid complex and solid dispersion and its pharmacokinetic were studied systematically and deeply, which was useful to set up a foundation for the clinical use.Dihydromyricetin was isolated and purified from ampelosis grossedetata by using recrystallation method which was easy and efficient. High-performance liquid chromatography with UV detection was developed to determine dihydromyricetin, which was accurate and simple.The ratio of combination of dihydromyricetin and phospholipid was regarded as the assessment standard, and the reactive solvent, the ratio of the reactant, the reactive time, the concentration of drug and the reactive temperature were chosed as the investigated factors, the condition of preparing the phospholipid complex was determined. Through DSC and X-ray diffraction, it was affirmed that phospholipid complex was prepared successfully and the character of crystal of dihydromyricetin disappeared and changed into amorphism form. Compared with dihydromyricetin, the liposoluble was enhanced distinctly and the affinity for cellula was also improved. Moreover, HPLC method was developed to determine dihydromyricetin in phospholipid complex, which was provided for the establishment of qualification standard of preparation. PVPK₃₀ was chosed as carrier after investigating the effect of PEG and PVP on the dissolution of dihydromyricetin. Solid dispersion was prepared by using solvent evaporation method with denatured ethanol as the solvent. Through DSC and X-ray diffraction, it was sure that thermal characteristic of dihydromyricetin was sheltered and solid dispersion was in an amorphism form. It was indicated that the rate of dissolution was promoted significantly after the solid dispersion was formed with PVPK30.A HPLC-UV method was developed for determination of dihydromyricetin in rat plasma. The plasma sample was separated on a ODS column and detected under 291 nm after liquid-liquid extraction by ethyl acetate, using methol-2.5% acetic acid (33:67, v/v) as mobile phase and 4'-hydroxyacetophenone as internal standard. By methodological validation, the analytical method was proved to be exclusive, sensitive, and the recovery rate was higher compared with other methods and it was suitable for bioavailability test of dihydromyricetin. After an oral administration of dihydromyricetin, phospholipid complex, solid dispersion at a dose of 600 mg·kg^-1, the drug concentration in plasma was determined at different time. As a result, the bioavailability of phospholipid complex, solid dispersion were 175.3% and 202.5% of dihydromyricetin respectively, the relative bioavailability were significantly improved.