Compared with the traditional passive drug delivery, what are the advantages of the active drug delivery method of liposomes? how does it work?

The invention of active drug loading method improves the encapsulation efficiency of some ionizable hydrophilic drugs (weak acid or weak base). The specific method is to construct pH gradient inside and outside the liposome, and then use the solubility difference of ionizable drugs under different pH conditions to realize the drug loading. With this method, the drug encapsulation rate can reach more than 95% and the drug loading can reach about 10%.

Explanation:

https://www.creative-biostructure.com/liposomes-in-drug-delivery-491.htm

it's c. (to reduce the greenhouse effect/carbon gasses)