Fluid from {HEAD ~ the environment} is imbibed through a semipermeable plug into the water swellable agent chamber and the active agent formulation is released through {TAIL ~ a back diffusion} regulating outlet 
Fluid from { HEAD ~ the environment } is imbibed through a semipermeable plug into the water swellable agent chamber and the active agent formulation is released through { TAIL ~ a back diffusion } regulating outlet
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH