Hello, the hydrophobic drug will be quite difficult to incorporate in exosome unless you have a specific binding strategy or you know that it will go in the membranes. For the hydrophilic drug, you can concentrate your exosome and add the drug...then you could use a sonicator (to create pores in the membranes) and let them rest for 2 hours (you could also pass them trough a filter here if you want). Then you can procede with the separation to see if your drug is inside the exosome or not.