Preparation Of Baicalein Emulsion And Freeze-dried Powder Injection

Baicalein is one of the active ingredients extracted from traditional Chinese scutellaria baicalensis georgi with a wide range of pharmacological effects, which include antibacterial, antiviral, protecting the liver function, antioxidant, anticancer, and etc. Due to the low oral bioavailability and longer onset time of baicalein, it cannot be used for accident and emergency treatment, so that it is urgent to develop baicalein injections. At present, there is no pharmaceutical product in the market.However, baicalein is insoluble in water and unstable in alkaline solution, which makes it difficult to be prepared into the injection. The difficulty of this topic is to improve the solubility of baicalein. The objective of the present study is to prepare a safe and stable baicalein injection. A variety of means were carried out to improve the dispersion of baicalein in water combined with physical and chemical properties of baicalein, and two methods were finally determined to prepare baicalein emulsion and baicalein freeze-dried powder.The assaying methods of baicalein were established, and these results showed the methodology to meet the requirement.An optimized formulation was obtained by single-factor method, which was used to study the effect of several factors on the dispersion of baicalein in water. Then the obtained baicalein emulsion was characterized by investigating particle size distribution and stability. To prepare baicalein emulsion, medium chain triglycerides as the organic phase and lecithin S75 as the emulsifier were determined. The solution was dripped to1.2% lecithin S75 aqueous dispersion when baicalein was dissolved. Finally, baicalein emulsion was obtained when the ultrasonic power was 280 W with 3 min. The particle size of emulsion was 168 nm. The zeta potential was-37.28 mV. The emulsion showed a good stability after the centrifugation. The optimized preparation of freeze-dried powder process was as follows: In organic phase, the ratio of lecithin S75 and solutol was 9:4, in which baicalein was dissolved, and the solution was dripped to 1.86% lecithin S75 aqueous phase. The baicalein freeze-dried powder injection was obtained when the ultrasonic power was 260 W with 1 min, and the 5% mannitol lyoprotectant was selected.Under the condition, the average particle size was(113.3 ± 5.3) nm, which was observed a round shape by transmission electron microscope(TEM). The preparation of baicaleinfreeze-dried powder injection significantly enhances the dispersion of baicalein in water,which has a uniform particle size distribution, stability and safety easy to save.