Biodegradable Drug Delivery Composition

A composition comprising:

• a vehicle comprising:
• sucrose acetate isobutyrate,
• a biodegradable polymer present in an amount of from about 5% to about 40% by weight of the vehicle, the biodegradable polymer having a weight average molecular weight ranging from 2000 Daltons to 10,000 Daltons, and
• a hydrophobic solvent present in an amount of from about 60% to about 95% by weight of the vehicle;
• and
• a complex dispersed in the vehicle, the complex having a solubility of less than 1 mg/mL in the vehicle at 25° C.,
• wherein the complex comprises:
• a protein, peptide, nucleic acid, or low molecular weight compound, the low molecular weight compound having a molecular weight of less than or equal to about 800 Daltons, and
• a counterion of the protein, peptide, nucleic acid, or low molecular weight compound,
• wherein the composition has a zero shear viscosity less than 1,200 centipoise at 25° C., and
• wherein the composition is not an emulsion.