Abstract: Microspheres which are a matrix of a biocompatible and biodegradable polymer which is soluble in an organic solvent which is immiscible in water, within which a water-soluble substance is uniformly distributed, and wherein the residual level of toxic solvent in the microspheres is lower than 1.5% by weight, progressively and continuously releases the substance over a period of at least 8 days when the microspheres are placed in an aqueous physiological environment, with a reduced or substantially absent first phase of accelerated release. A process for producing such microspheres is provided.

Abstract: The subject of the present invention is a process for preparing microparticles of the microsphere type of a water-soluble substance and a biocompatible and biodegradable polymer controlling the kinetics of release of the said substance consisting of a matrix of the said polymer within which the said water-soluble substance is regularly dispersed, characterized in thata) the said polymer is dissolved in a first volatile organic solvent immiscible with water,b) the said water-soluble substance is dissolved in a second solvent which is miscible with the said first solvent, is a solvent for the polymer, and miscible with water,c) the solution of the said substance and the solution of the said polymer are mixed,d) an organic phase of the polymer and of the said substance is obtained which is then emulsified in an immiscible dispersant medium consisting of an aqueous phase containing an emulsifying agent,e) the two solvents are then removed from the microspheres being formed with stirring, the first solvent being r

Abstract: The present invention relates to a process for preparing lipid microparticles of microcrystalline appearance, of a water-insoluble substance possessing an affinity for phospholipids and of at least one phospholipid, the microparticles being stable in suspension in an aqueous solution, characterized in that:a) the said substance and the said phospholipid or phospholipids are dissolved in a common organic solvent for the said substance and for the said phospholipid or phospholipids,b) the solution of said substance and of the said phospholipid or phospholipids is mixed with an aqueous solution in an amount such that an insolubilization takes place in the form of a precipitate, andc) the organic solution is removed to recover an aqueous solution containing the microparticles in the form of microsuspensions.