Process for producing a solid dispersion of a biologically active substance comprising alimentarel active ingredient and a forming agent matrix to an extruder and forming a uniform extrudate, Elque the extruder comprises at least two shafts (2) of rotation, each carrying one of the shafts (2) unapluralidad of processing elements disposed axially one behind the other, defining deprocesamiento elements (i) a section (A) feed and transport (ii) at least one section (R D) reverse thread and (iii) a section (E) discharge, in which the processing elements defining section (R D) reverse thread comprise at least doselementos (14) reverse thread and at least one element (3) screw type positive thread arranged between dichosdos elements (14) of reverse thread and wherein said at least two elements (14) reverse screw are based each on an element of type tornilloque has an opposite direction of transport to the general sense of transport of the extruder, wherein the screw pitch of said at least two elements (14) of reverse thread is in a range of from (-0.8) sometimes (-1.2) times the pitch of the screw / of the element (s) (3) screw type positive thread disposed (s) between at least two elements (14) of reverse thread.Procedimiento para producir una dispersión sólida de un principio biológicamente activo que comprende alimentarel principio activo y un agente de formación de matriz a una extrusora y formar un producto extruido uniforme, en elque la extrusora comprende al menos dos árboles (2) de rotación, llevando cada uno de los árboles (2) unapluralidad de elementos de procesamiento dispuestos axialmente uno detrás del otro, definiendo los elementos deprocesamiento (i) una sección (A) de alimentación y transporte (ii) al menos una sección (R D) de rosca inversa, y (iii) una sección (E) de descarga, en el que los elementos de procesamiento que definen la sección (R D) de rosca inversa comprenden al menos doselementos (14) de rosca inversa y al menos un elemento (3) de tipo tor
