The Research Of Extracts Of Bioactive Site Of Scutellaria Baicalensis Georgi Sustained-Release Pellets

Scutellaria baicalensis Georgi is an effective traditional Chinese medicine, and listed in the first section of the 2000's edition of "Pharmacopoeia of the People's Republic of China". It has the functions of dispelling wind-heat to reduce fever and detoxifcating. The thesis was aiming at the research of the extracts of bioactive site of S. baicalensis, consisting of preparation of solid dispersion, and then, with other excipients, preparing extracts of bioactive site of S. baicalensis sustained-release pellets. The coated pellets were evaluated by in vitro and in vivo methods.Ultraviolet spectrophotometry method was developed for assaying during the study of physiochemical properties of the drug and release rate of the pellets. High-performance liquid chromatography with UV detection was developed for determining content of the pellets and content of baicalein in the extracts of bioactive site of S. baicalensis. Taking baicalein and wogonin as determining target, the thesis established HPLC method to monitor the plasma level in vivo in dogs and rats. The methods were sensitive, accurate and simple, suitable for the analysis of the thesis.The thesis analyzed some physicochemical properties of material drug, which were connected closely with pharmaceutic form design. The solubility results showed the extracts were poorly soluble. So the thesis prepared solidABSTRACTdispersion which increased markedly the solubility and dissolution rate of the extracts. It was beneficial to prepare the pellets next step.The process included the preparation of prompt-release pellets and coating of the pellets. Prompt-release pellets were prepared by the method of extrusion-spheronization. Based on the studies of the influence factors. Orthogonal test was used to optimize the experiment conditions. A fluid bed spray processor was adopted for coating the pellets. Using Eudragit NE30D and Aquacoat as coating material, the thesis screened the coating process parameters, and produced the sustained-release pellets according to the design. The description of dissolution profiles suggested that among the kinetics, the first-order became the most appropriate model to describe. The stability of the coated pellets was monitored. The results showed the coated pellets were stable under high temperature, high humidity, strong light and accelerating test.Oral administering the extracts and the solid dispersion to rats, plasma concentration was monitored and the pharmacokinetic parameters were computed. The results showed AUC of solid dispersion was 3.52 times as much as of the extracts. So it was obvious that solid dispersion improved administration of the drug in vivo, and increased the relative bioavailability. Pharmacokinetic studies of sustained-release and prompt-release capsule in dogs were performed based on determination of plasma concentration of drugs. The results showed, compared with prompt-release capsule, plasma concentration of sustained-release capsule was relatively stable, Tmax was postponed and Cmax was lowered. The correlation study showed that a good relationship between in vivo and in vitro was built.