for 1 5 hours to prepare another mixture afterward washing this mixture with 80 w w nacl aqueous solution four times 50 ml per time taking a toluene layer out of this mixture and vaporizing toluene in the vaporizer under reduced pressure to leave residue using 150 ml methanol to wash the residue and filtering insoluble materials therein to leave filtrate thereafter extracting the filtrate with ether in an amount equal to the filtrate to obtain extract then vaporizing ether in the extract 0 153 g cholesterol peg 600 is thus prepared adding 2 478 g stigmasterol and 1 6 triethylamine to 40 ml dry toluene to prepare solution a adding 2 42 g adipoyl chloride to 40 ml dry toluene to prepare solution b slowly adding solution b to solution a at a flow rate of 3 ml min to prepare a mixture stirring for 1 5 hours at a temperature of 12 u00b0 c then centrifugalizing the mixture and filtering it to obtain filtrate keeping the filtrate for subsequent use next adding 14 4 g polyethylene glycol 600 peg600 and 2 4 triethylamine to 40 ml dry toluene to prepare a mixture and then adding the mixture to the aforementioned filtrate stirring for 1 5 hours to prepare another mixture afterward washing this mixture with 80 w w nacl aqueous solution four times 25 ml per time taking a toluene.