Process for the preparation of a controlled porosity osmotic pump for controlled release of Diltiazem L-malate and osmotic pump thus obtained

摘要

The instant invention is directed to an osmotic pump, for the controlled release of diltiazem L-malate to an environment of use, said pump comprising: (A) a core which comprises a therapeutically effective amount of diltiazem L-malate and an effective buffering amount of sodium bitartrate surrounded by (B) a rate controlling water insoluble wall, having a fluid permeability of 6.96 x 10-18 to 6.96 x 10-14 cm3 sec/g and a reflection coefficient of less than 0.5, prepared from: (i) a polymer permeable to water but impermeable to solute and (ii) 0.1 to 60% by weight, based on the total weight of (i) and (ii), of at least one pH insensitive pore forming additive dispersed throughout said wall. The instant invention is also directed to a multiparticulate osmotic pump, for the controlled release of diltiazem L-malate to an environment of use, said pump comprising: (I) a carrier medium which does not maintain its integrity in the environment of use; and (II) a multiple of tiny osmotic pump elements, as described above.