STABILITY OF CYCLOSPORINE IN AN EXTEMPORANEOUSLY COMPOUNDED PASTE

The stability of cyclosporine in an extemporaneously compounded paste was studied. Cyclosporine oral solution 100 mg/mL was mixed with an ad hesive gel to prepare six aluminum-lined ointment tubes containing pas te with cyclosporine 9.6 mg/g. Two of the tubes were stored at 37 degr ees C, two at 21 degrees C, and two at 2 degrees C. Cyclosporine was e xtracted from samples taken on days 2, 4, 5, 7, 9, 14, 18, 22, 28, and 31, and the concentration was measured by high-performance liquid chr omatography (except for samples obtained on day 2) and fluorescence po larization immunoassay. Throughout the study period, the concentration of cyclosporine remaining in the paste was >90% of the initial concen tration according to both assay methods.Cyclosporine 9.6 mg/g in a pas te compounded extemporaneously from cyclosporine oral solution and an adhesive gel was stable for at least 31 days when stored in aluminum-l ined ointment tubes at 37, 21, and 2 degrees C.