Answer:
a cell membrane is made up of 3 main ingredients, that are-
phospholipids, cholesterol and proteins. cell membrane is consists of lipid bilayer, cholesterols and integral and peripheral proteins. among them, lipid is largest portion that cell membrane has.
so, if a drug needs to be uptaken by the cell in a better manner then it has to couple with lipids. By coupling up with the lipids is the easiest and better way to be uptaken by the desired cell.