It is an object of the present invention a method to introduce compounds inside red blood cells comprising: providing red blood cells from a subject; providing one or more compounds to be encapsulated in said red blood cells; providing a loading device comprising a microporous matrix; feeding said loading device with a suspension comprising said red blood cells and said one or more compounds; collecting the red blood cells exiting from said loading device, which are encapsulated red blood cells; characterized in that: said red blood cells and said one or more compound are in suspension at a pH of between 6.8 and 7.8, preferably of between 7.35 and 7.45; the pores in said microporous matrix have a minimum size of at least 3 times the size of a red blood cell, that is a minimum size of at least 20 m; the pores in said microporous matrix have an average size of between 30 and 500 m, or of between 40 and 400 m, or of between 50 and 350 m, or of between 100 and 250 m; said porous matrix has a length L of at least 1 mm and a width W and a height H such that it comprises at least one unit cell, said unit cell being equal to the microporous matrix volume that, repeated by rototranslation through the vectors that generate the matrix, fills the whole matrix itself; wherein said loading device is fed with said suspension in such a way to obtain an average fluid speed of between 10.sup.4 and 10 m/s. Further objects of the present invention are a microporous matrix, a loading device comprising the same, a fluidic circuit and a machine for implementing said method and red blood cells encapsulated with at least one compound according to said method.