Controlled release preparations of active materials.

摘要

A controlled release preparation of an active material comprising a reaction product obtained by reacting (a) a copolymer consisting essentially of maleic anhydride and at least one polyalkylene glycol ether represented by (I): wherein B represents a residue of a compound having from 2 to 8 hydroxyl groups; R<1> represents an alkenyl group having from 2 to 5 carbon atoms; AO represents an oxyalkylene group having from 2 to 18 carbon atoms or a combination thereof which may be linked together in blocks or at random; R<2> represents a hydrocarbon group having from 1 to 24 carbon atoms; a represents a positive integer, b and c each represents 0 or a positive integer, and a + b + c = 2 to 8; l >/= 0, m >/= 0, n >/= 0, and l + m + n = 1 to 1000; and (b) an active material. The preparation is soluble both in water and in an organic solvent and exhibits activity for a prolonged period of time.