| Summary: | 碩士 === 高雄醫學大學 === 藥學研究所碩士班 === 94 === The medicinal plant Scutellaria baicalensis Georgi (Lamiaceae) (SR) has been used widely in traditional Chinese medicine for antipyretic and anti-inflammation. Baicalein is the main ingredient of SR and plays an import role in medicine due to its mechanism of reducing the production of pro-inflammatory enzyme and consequently decreasing the release of PEG2. This study was to estimate the antipyretic effect of baicalin and baicalein with different dose in rats by observing the relationship between time and rate of antipyretic effect. The results was shown that low dose of SR could produce better antipyretic effect than of higher dose. After orally and intravenously administration of freeze-dried powder of SR decoction injected into the rat, the blood concentration of baicalein could not be detected by HPLC. It was confirmed that baicalein was fastly eliminated in blood. The formulation of SLN prepared with Gelucire (62/5, 48/9 and 44/14) and glyceryl monostearate as lipid phase and Vitamin C and Vitamine E as antioxidant to overcome the problem. The formulation was evaluated by measuring the average particle size and the content of baicalein at 6th day. The SLN with the highest entrapment efficiency was composed of Gelucire 62/5 with 8 mg of Vitamin C, and then was intravenously administrated into the rat. The pharmacokinetics and distribution of baicalein in brain tissue were evaluated in rat. It was found that baicalein formulated by SLN could increase the t1/2 and MRT by 1 hr, decrease the clearance and increase the AUC in plasma. The Cmax of baicalein-SLN was 5-fold higher than that resulted from baicalein-solution and thereby increased the plasma concentration. It was suggested that SLN could extend the period of baicalein in blood. High concentration of baicalein was found in the thalamus of the rat. It proved that baicalein could transport through the blood-brain barrier to consequently produce the antipyretic effect.
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