In other words, while the substantially non dissolvable region or layer may be somewhat soluble in {HEAD ~ water}, the dissolvable region or layer will have a substantially greater solubility in water so as to dissolve, leaving the non dissolvable region or layer substantially intact at the end of the useful life of {TAIL ~ the shaped composition} 
In other words , while the substantially non dissolvable region or layer may be somewhat soluble in { HEAD ~ water } , the dissolvable region or layer will have a substantially greater solubility in water so as to dissolve , leaving the non dissolvable region or layer substantially intact at the end of the useful life of { TAIL ~ the shaped composition }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL