A suspension formulation of an insulinotropic peptide (e.g., glucagon-like peptide-1 (GLP-1) or exenatide) is described. The suspension formulation comprises (i) a non-aqueous, single-phase vehicle, comprising one or more polymer and one or more one solvent, wherein the vehicle exhibits viscous fluid characteristics, and (ii) a particle formulation comprising the insulinotropic peptide, wherein the peptide is dispersed in the vehicle. The particle formulation further includes a stabilizing component comprising one or more stabilizers, for example, carbohydrates, antioxidants, amino acids, and buffers. Devices for delivering the suspension formulations and methods of use are also described.