Stability of an extemporaneously prepared clopidogrel oral suspension

The stability of an extemporaneously prepared clopidogrel oral suspension was studied. Methods Clopidogrel oral suspension (5 mg/mL) was prepared using clopidogrel bisulfate tablets, Ora-Plus, and Ora-Sweet. Six 2-oz samples were prepared; three were stored at room temperature and three under refrigeration. One milliliter was withdrawn from each sample, diluted to 10 mL with methanol, and exposed to high-frequency sound waves in a water bath to ensure complete dissolution of clopidogrel. A 300-microL sample was then withdrawn, diluted with mobile phase to an expected concentration of 15 microg/mL, and assayed in duplicate using high- performance liquid chromatography immediately after preparation and at 7, 14, 28, and 60 days. The stability of the clopidogrel suspension was determined by calculating the percentage of the initial concentration remaining on each test day. Stability was defined as retention of at least 90% of the initial concentration.At least 97% of the initial clopidogrel concentration remained throughout the 60-day study period, regardless of storage conditions. There were no detectable changes in color, odor, taste, or pH and no visible microbial growth in any sample. The preparation was palatable, with a slightly gritty consistency and a slightly bitter aftertaste; the bitterness intensified slightly between 28 and 60 days but remained fairly mild.Extemporaneously compounded suspensions of clopidogrel, 5 mg/mL, in a 1:1 mixture of Ora-Plus and Ora-Sweet were stable for at least 60 days when stored in amber plastic bottles at room temperature and under refrigeration.