HUP0002406A2 - Process for the selection of particles of a preselected size from a particulate pharmaceutical product - Google Patents

Abstract

Selection from particulate pharmaceutical product (PPP) of particles of a preselected size comprises: (i) obtaining a homogeneous suspension (S1) of PPP in a fluid suspension medium which is immiscible with PPP and is of a different density to PPP; (ii) carrying out a size selection procedure to set a lower or upper size limit on the particles in the final particulate product; and (iii) optionally carrying out a further size selection procedure to produce a particulate product containing particles of the preselected size; where step (ii) comprises either: (a) allowing S1 to settle for a period; (b) separating S1 into 2 components (Sc1 and Sc2) in a predetermined ratio where Sc1 and Sc2 contain the upper and lower layers of S1 respectively; (c) adding further suspension medium (SM) to Sc1 where SM is denser than the pharmaceutical product (PP) or to Sc2 where SM is less dense than PP and mixing to give a homogeneous suspension in SM; and (d) repeating steps (a)-(c) at least once, optionally omitting (c); or (a1) allowing S1 to settle for a period; (b1) separating S1 into a third (Sc3) and fourth (Sc4) components in a second predetermined ratio where Sc3 and Sc4 contain the upper and lower layers of S1 respectively, Sc3 is retained in SM less dense than PP and Sc4 in SM denser than PP, and the second predetermined ratio is such as to set an upper size limit on the particles in the retained component; and (c1) optionally adding more SM to the non-retained component and mixing to produce a homogeneous suspension; (d1) repeating steps (a1)-(c1) at least once, optionally omitting (c1) and (e1) collecting the retained components from (d1). Also claimed are: (A) a particulate pharmaceutical separation apparatus comprising a sterilisable separation chamber (1) having vertical sides, a horizontal base with several bottom outlets (7) and a stirrer (4); and (B) an ultrasound contrast medium having monodispersed particles in a carrier liquid, where the particles are, or are in vivo, echogenic.