The stability and availability of cyclosporine from the oral dosage form when stored in plastic syringes were examined. Solutions of cyclosporine were stored in plastic syringes for 28 days at 25 degrees C. Half of the solutions remained in room light, and samples were obtained at 3, 6, and 12 hours and 1, 2, 3, 4, 5, 6, 7, 14, 21, and 28 days. The remaining samples were protected from light, and samples were obtained at 1, 3, 5, 7, 14, 21, and 28 days. Samples stored in plastic were compared with control solutions stored in the original amber bottle. All samples were analyzed for unchanged cyclosporine by high-pressure liquid chromatography. Cyclosporine was stable and completely available from the oral dosage form when stored in plastic syringes for up to 28 days. There was no difference in the stability of cyclosporine between the solutions exposed to room light and those protected from light. Solutions of the oral dosage form of cyclosporine may be stored in plastic syringes without protection from light for up to 28 days.