described and claimed are biologically useful crosslinked copolymers of vinyl pyrrolidone and allylamine suitable for various preventative and therapeutic applications to intact or injured skin . coatings of these copolymers , either preformed or prepared in situ on the skin may deliver medicaments to the skin , may serve as an iontophoretic medium , may provide electrical contact with the body , may regulate or control moisture loss from injured integument . monolithic devices for the delivery of pharmaceutically active agents within living tissue may be formulated from these copolymers .