Slow-release matrix pellets with a spherical or lenticular shape and uniform maximum diameters in the range from 0.5 to 4 mm, composed of a) 0.1-87% by weight of at least one biologically active compound, b) 5-50% by weight of at least one water-insoluble polymer, c) 5-45% by weight of at least one lipophilic component as plasticizer for polymer b), d) 3-40% by weight of a natural or semisynthetic gel former, e) 0-50% by weight of one or more conventional formulation aids.