i) {HEAD ~ a linear polymer} selected from the group consisting of {TAIL ~ linear hydrophobic biodegradable polymers} and linear non degradable hydrophilic polymers 
i ) { HEAD ~ a linear polymer } selected from the group consisting of { TAIL ~ linear hydrophobic biodegradable polymers } and linear non degradable hydrophilic polymers
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH