One month of sustained release of insulin from a polymer implant

Rats made diabetic with streptozotocin received a single subcutaneous implant of an insulin polymer pellet that released insulin continuously at approximately 2 U/day. Continuous normoglycemia was achieved for up to 1 mo. Mean glucose level for treated animals was 113 mg/dl as compared with 398 mg/dl for untreated diabetic controls. Diurnal blood glucose values for treated animals ranged from 71 to 116 mg/dl. Polyuria and glycosuria were corrected by the presence of the insulin + polymer. Treated animals gained weight normally and reached a mean weight of 350 g, whereas untreated control animals lost weight, to a mean of 150 g. When insulin + polymer preparations were periodically implanted and removed at 7-day intervals, normoglycemia was only associated with the presence of implants.