For insulin infusion: a miniature precision peristaltic pump and silicone rubber reservoir

This paper describes a miniature precision peristaltic pump and a silicone rubber reservoir developed for the infusion of insulin in diabetic subjects. The ability of the 100-ml reservoir to maintain sterility of its contents over 26 refilling cycles (48 days) is demonstrated. Accelerated bench tests on 10 pumps over 30 days indicate an accuracy of +/- 1% on flow rate whether measured over 10 min or 24 h and with or without 1 atm of outlet back pressure. Comparison of calibrations made before and after 58 animal and clinical tests of 6--71 days' duration showed a percentage difference in calibration that varied with a mean +/- SD of 0.05 +/- 3.09%. Microscopic examination of pump tube samples after 21 days of clinical use indicated redistribution of surface material without evidence of particle spallation. Samples subjected to accelerated wear equivalent to 620 days of clinical use showed extensive luminal surface modification and particulate deposits on downstream filters. These were identified by X-ray spectroscopy as silicon compounds.