Future direction of synthetic polyanions (pyran copolymer).

Pyran copolymer (maleic anhydride-divinyl ether) has consistently reproducible molecular weight-related biologic effects associated with toxic, immunologic antitumor, and antiviral effects. Fortunately, the antitumor action occurs with the least toxic lower molecular weight fraction. Immunoadjuvant effects with this fraction would be critical to its development. Studies of polymers should include evaluation of effects on splenomegaly, splenic esterase changes, lipolysis, reverse transcriptase, nucleases, calcium flux, cyclic nucleotides, and complement and clotting elements.