Objective To study the water extraction process of Zhuyu Zhitong gel paste .Methods With the yields of paeoniflorin and the dry paste as target ,the water extraction process of Zhuyu Zhitong gel paste was optimized by an orthogo-nal experimental design based on the single factor experiment .Results The optimized water extraction process of Zhuyu Zhi-tong gel paste was soaking the materials for 1 h with 8 times of water ,then extracting 1 .5 h for three times with the same a-mount of water .Conclusion The optimized extraction process was consistent ,reasonable and feasible for large production .

Human metapneumovirus, first identified in the Netherlands in 2001, is a common respiratory virus belonging to the genus Metapneumovirus of the family Pneumoviridae. It has spread across the world. It can cause repeat infections in infants, young children, the elderly, and immunocompromised people, and lead to acute respiratory infections. There are currently no effective prophylactic vaccines approved for marketing. This article mainly focuses on the virological and epidemiological characteristics of human metapneumovirus, introduces the structure of fusion protein, a potential key immunogen for vaccine development, and the antigenic loci on fusion protein, and summarizes the research progress in subunit vaccines, live attenuated vaccines, and nucleic acid vaccines designed based on fusion protein.