A method of making a tablet of a pharmaceutical compound which comprises; (a) preparing uncoated pellets containing a pharmaceutical compound; (b) dispersing said uncoated pellets in a matrix which comprises a swellable polymer; and (c) compressing said matrix into a tablet; wherein in step a) the pellets are prepared by (i) forming a powder mixture which comprises a binder and a pharmaceutical compound; (ii) feeding said powder mixture which is optionally pre-wetted with from 0-60wt% of a pharmaceutically acceptable liquid diluent, based on the total weight of the powder mixture and the pharmaceutically acceptable diluent, to an operating apparatus which comprises a rotor chamber having an axially extending cylindrical wall, means for passing air through said chamber from the bottom, spray means for feeding a liquid into said chamber, a rotor which rotates on a vertical rotor axis, said rotor being mounted in said rotor chamber, said rotor having a central horizontal surface and, in at least the radial outer third of said rotor, the shape of a conical shell with an outward and upward inclination of between 10° and 80°, said conical shell having a circularly shaped upper edge which lies in a plane which is perpendicular to the rotor axis, feed ports for introducing powder, a plurality of guide vanes having an outer end affixed statically to said cylindrical wall of said rotor chamber above a plane formed by the upper edge of said conical shell of said rotor and an inner end which extends into said rotor chamber and is affixed tangentially to said cylindrical wall of said rotor chamber and having, in cross-section to the rotor axis, essentially the shape of an arc of a circle or a spiral, such that said powdered product which is circulated by kinetic energy by said rotor under the influence of kinetic energy, moves from said rotor to an inside surface of said guide vanes before falling back onto said rotor; (iii) rotating said rotor, while feeding air and spraying a pharmaceutically acceptable liquid into said rotor chamber for a sufficient amount of time to form solid pellets having a desired diameter; and (iv) feeding a sufficient amount of a substantially dry, free flowing inert powder which forms a non-tacky surface when placed in contact with water to provide on said pellets an outer zone comprising a layer formed from said substantially dry, free flowing inert powder. (a) preparing uncoated pellets containing a pharmaceutical compound; (b) dispersing said uncoated pellets in a matrix which comprises a swellable polymer; and (c) compressing said matrix into a tablet; (i) forming a powder mixture which comprises a binder and a pharmaceutical compound; (ii) feeding said powder mixture which is optionally pre-wetted with from 0-60wt% of a pharmaceutically acceptable liquid diluent, based on the total weight of the powder mixture and the pharmaceutically acceptable diluent, to an operating apparatus which comprises a rotor chamber having an axially extending cylindrical wall, means for passing air through said chamber from the bottom, spray means for feeding a liquid into said chamber, a rotor which rotates on a vertical rotor axis, said rotor being mounted in said rotor chamber, said rotor having a central horizontal surface and, in at least the radial outer third of said rotor, the shape of a conical shell with an outward and upward inclination of between 10° and 80°, said conical shell having a circularly shaped upper edge which lies in a plane which is perpendicular to the rotor axis, feed ports for introducing powder, a plurality of guide vanes having an outer end affixed statically to said cylindrical wall of said rotor chamber above a plane formed by the upper edge of said conical shell of said rotor and an inner end which extends into said rotor chamber and is affixed tangentially to said cylindrical wall of said rotor chamber and having, in cross-section to the rotor axis, essentially the shape of an arc of a circle or a spiral, such that said powdered product which is circulated by kinetic energy by said rotor under the influence of kinetic energy, moves from said rotor to an inside surface of said guide vanes before falling back onto said rotor; (iii) rotating said rotor, while feeding air and spraying a pharmaceutically acceptable liquid into said rotor chamber for a sufficient amount of time to form solid pellets having a desired diameter; and (iv) feeding a sufficient amount of a substantially dry, free flowing inert powder which forms a non-tacky surface when placed in contact with water to provide on said pellets an outer zone comprising a layer formed from said substantially dry, free flowing inert powder.