In still another aspect, the invention is directed to {HEAD ~ an impermeable active agent delivery system} for delivering {TAIL ~ an active agent} that is susceptible to degradation 
In still another aspect , the invention is directed to { HEAD ~ an impermeable active agent delivery system } for delivering { TAIL ~ an active agent } that is susceptible to degradation
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH