1. The first purpose of preparing derivatives by drug esterification is to increase the lipophilicity (oil solubility) of drugs (for example, artesunate is an oil-soluble injection), which is also beneficial to absorption; The second is to enhance the stability of drugs (such as artemisinin itself is unstable).

2. Why not choose other acids? And use succinic acid?

(1) There are many organic acids that can be used to prepare derivatives by drug esterification, including not only succinic acid, but also lactic acid, malic acid, tartaric acid, citric acid and acetic acid. Most of them come from natural medicines. On the one hand, their safety is guaranteed, on the other hand, they also have certain medicinal value.

(2) Succinic acid, another name, was originally obtained by distilling amber. Succinic acid is an intermediate product in the process of glucose metabolism in vivo. Its own functions are: a, antibacterial effect; B, the central aspect has anticonvulsant effect; C, anti-ulcer effect; D, it can inhibit passive and active skin allergic reactions and reduce the formation of 1gE antibody in animal serum; E, detoxification: succinic acid has obvious protective effect on mice in poisonous cobra; F, spasmolytic, expectorant and diuretic effects. The above effects will not be contrary to the antimalarial effect of artemisinin, and the esterification efficiency with artemisinin is high, so artemisinin is mostly esterified with succinic acid.

(3) succinic acid, fumaric acid, tartaric acid, adipic acid, malic acid, citric acid, etc. It is also a food acidulant.