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