Pharmacological composition containing polyelectrolyte complexes in microparticulate form and at least one active agent

A pharmaceutical composition consisting essentially of:

• a) a polyelectrolyte complex in microparticulate form,
• wherein said polyelectrolyte complex has an average particle size of less than 15 .mu.m and is comprised of a polybase and a polyacid,
• wherein at least one of said polyacid and said polybase is a polymer, and
• wherein when said polyacid is a polymer, the polymer is selected from the group consisting of xylan polysulfates, dextran sulfates, poly(amino acids), polysaccharide polysulfates, inulin sulfates, hydroxyethylstarch sulfates, polysaccharide polysulfonates, polysaccharide polyphosphates, polyphosphates, and derivatives of said polymer, and
• wherein when said polybase is a polymer, the polymer is selected from the group consisting of poly-L-lysine, poly-.alpha.,.beta.-(2-dimethylaminoethyl)-D,L-aspartamide, chitosan, lysine octadecyl ester, aminated dextrans, aminated cyclodextrins, aminated cellulose ethers, aminated pectins, and derivatives of said polymer;
• and
• b) a pharmaceutically effective amount of at least one active agent selected from the group consisting of an enzyme inhibitor, an antigen, a cytostatic, an antiinflammatory agent, an antibiotic, a vaccine and an ultrasonic contrast agent.