FIELD: medicine.
SUBSTANCE: invention relates to the production of biodegradable microparticles formed from polylactide-polyglycolide copolymers (PLGA) and to providing sigmoidal release of risperidone from said microparticles. Described are versions of a process for the preparation of biodegradable microparticles from D, L-lactide and glycolide (PLGA) copolymer, characterised by a sigmoidal release profile of risperidone, which is contained in microparticles, comprising the following steps: a) preparing an inner oil phase by dissolving the PLGA polymer and risperidone in an organic solvent, wherein the concentration of the polymer in the inner oil phase is in the range of 5-8% by weight; b) preparing an outer aqueous phase consisting of water, polyvinyl alcohol (PVA), optionally an aqueous buffer solution to bring pH to a value, where risperidone is characterised by a lower solubility, and the same organic solvent as used in the oil phase, wherein the amount of the organic solvent added to the outer phase is sufficient to saturate the outer phase; c) emulsifying the inner phase in the outer phase, either by mechanical stirring or using a high shear homogeniser; d) feeding the emulsion into a cooling medium at a temperature set at 5°C, and with thermostatic control; e) separating of the resultant solidified microparticles, and optionally washing the microparticles; and f) drying the microparticles during one-stage drying without an additional washing and/or drying step.
EFFECT: technical result is an improved method for controlling the release profile of risperidone from biodegradable microparticles.
15 cl, 4 dwg, 1 tbl, 8 ex
