The aim of this work is the development of controlled delivery system immobilized by antimicrobial drug rifampicine on the basis of microparticles of alginate calcium gel, modified by natural polymer chitosan. Modified microparticles were obtained by syringed dropwise a solution of rifampicine in solution of sodium alginate was into a mixed solution of chitosan in calcium chloride. The obtained modified alginate microparticles were contained immobilized rifampicine and a surface layer of chitosan. Effects of chithosan concentration and exposure duration on the thickness of polymer coating were determined. For the determination of surface thickness a red congo dye has been used able to form a complex with chitosan. It has been established that with an increase in the concentration of a polymer from 0,3 up to 1,5 mass % the thickness of the modified layer increases from 5 up to 60 mcm, and an increase of the time of gel exposition in a 2,5% solution of chitosan from 30 min to 24 h results in an increase in thickness of a layer from 5 up to 20 mcm respectively. When studying an influence of pH of the medium upon an interaction of alginate and chitosan it was been observed a formation of a polyelectrolyte complex between a chitosan polycation and an alginate polyanion stabilized by ionic bonds. The release of rifampicine from the modified alginate gel particles into a physiological solution with different thickness of a chitosan coating were studied. It was shown that the characteristic maximums on the curve of release observe after 10, 30, 90 and 120 min for the samples without the coating and with the coating thickness of 55, 100 and 150 mcm respectively. The data obtained shown a possibility of the regulation of the rate of rifampicine relase from the modified alginate particles by way of alternation of thickness of the chitosan coating.