Stabilization of eptifibatide by cosolvents

Eptifibatide is a potent and highly specific inhibitor of platelet receptor glycoprotein IIb/IIIa and is indicated in the treatment of acute coronary syndrome. The commercial product Integrilin® (eptifibatide) Injection requires a cold/refrigerator storage condition. In an effort to improve the drug stability for room temperature storage and transportation, this study proposed a semi-aqueous formulation that contains 2 mg/ml eptifibatide, 10% ethanol, 40% propylene glycol and 50% 0.025 M citrate buffer. The stability study was conducted in the pH range 4.25-6.25 under accelerated temperatures: 48, 60, 72.5°C. The results indicate that the proposed semi-aqueous vehicles substantially increased the drug stability in comparison with aqueous vehicles. The predicted drug shelf-life T₉₀ at 25°C shows that an almost twofold increase can be achieved by formulating eptifibatide in the semi-aqueous vehicle, which is 60 months at its maximum stability of pH 5.75, as opposed to the 33 months in the aqueous vehicle at its maximum stability of pH 5.25.