BMS-686117 is an 11-mer GLP-1 receptor agonist with a short intrinsic pharmacokinetic half-life (t1/2) of ∼2 h. In order to develop an extended release formulation for once-daily (QD) subcutaneous administration, a non-covalently bonded Zn/BMS-686117 adduct with very low aqueous solubility was prepared through mixing zinc acetate and BMS-686117 solutions, followed by filtration or spray drying. At pH 6.8, free BMS-686117 concentration decreased continuously with the increase of Zn:BMS-686117 ratio. Furthermore, free BMS-686117 concentration increases in the presence of ethylenediaminetetraacetic acid (EDTA), indicating the reversibility of the zinc–peptide association. As solids, the glass transition temperature of Zn/BMS-686117 adduct increases with the increase of Zn:BMS-686117 ratio. A Zn/BMS-686117 adduct suspension, with a molar ratio of zinc:BMS-686117 of 3:1, was dosed subcutaneously to dogs along with two other solution formulations. The Zn/BMS-686117 adduct showed a prolonged BMS-686117 terminal t1/2 of 8.5 h, a mean residence time (MRT) of 16 h, and a Cmax value 6–8 times lower than the solution formulations. Additionally, the Zn/BMS-686117 was encapsulated into poly(lactide-co-glycolide) (PLGA) microspheres. The Zn/BMS-686117 microspheres showed an almost zero-order release profile in vitro for at least 18 days, with minimal initial burst, indicating the potential of using this approach for long-term sustained release.