Patent ID: 8728528

Claim:
A process for preparing low residual solvent level microparticles, comprising: (a) providing a dispersed phase comprising a polymer excipient in a weight amount of a dispersed phase solvent, W DP solvent , wherein the polymer excipient comprises: i) a non-water soluble block copolymer comprising a polyethylene glycol (PEG) hydrophilic block or blocks and a hydrophobic block or blocks; or ii) an admixture of non-water soluble block copolymers comprising a PEG hydrophilic block or blocks and a hydrophobic block or blocks; or iii) an admixture of a PEG hydrophilic, water soluble biocompatible polymer; and a non-water soluble, biocompatible and/or biodegradable polymer; (b) combining the dispersed phase with a continuous phase processing medium to form an emulsion wherein the dispersed phase is a discontinuous phase in the continuous phase; (c) combining the emulsion formed in (b) with a weight amount of an extraction phase solvent, W EP solvent , thereby forming microparticles; wherein the W EP solvent comprises water or a mixture of water and a fully water-miscible solvent, and (d) isolating the microparticles; wherein the amount of residual dispersed phase solvent present in the isolated microparticles is less than or equal to about 3 wt %, and is less than the amount of residual dispersed phase solvent present in microparticles produced by said process in the absence of PEG; the total amount of extraction phase solvent is W EP solvent, total defined by the formula: W EP ⁢ ⁢ solvent , total ≤ ER ⁡ [ W DP ⁢ ⁢ solvent , total S ] wherein W DP solvent, total , is the combined total amount of a particular dispersed phase solvent used in the process; S is the solubility of the dispersed phase solvent in water; and ER is the Extraction Ratio, wherein ER is less than or equal to about 10.