Entrapped in {HEAD ~ the liposomes} is {TAIL ~ the topoisomerase inhibitor} at a concentration of at least about 0.10 μmole drug per μmole lipid 
is
Entrapped in { HEAD ~ the liposomes } is { TAIL ~ the topoisomerase inhibitor } at a concentration of at least about 0.10 μmole drug per μmole lipid
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH