Rat intestine absorption kinetics study on cucurbitacin B-sodium deoxycholate/ phospholipid mixed nanomicelles with in vitro everted gut sacs model Study on preparation and in vitro transdermal penetration of betulinic acid ethosomes modified by sodium deoxycholate Determination of percutaneous absorption characteristics of Panax notoginseng saponins transfersomes by in vitro skin permeation method