Look like a large pen. They send a fine spray of insulin through the skin at high pressure- Tend to be expensive. A refillable cartridge holds insulin good for about 2 days. The needle and tubing need to be changed every other day and frequent glucose monitoring is necessary, but usually no more than if you take multi injections a day to keep tight control. Internal insulin pumps are surgically implanted, usually in the abdomen.
Users deliver insulin doses above and beyond the basal dose delivered by the pump during the day.
The insulin goes directly to the liver as would normally occur in a person without diabetes. The insulin patch is placed on the skin and gives a continuous low dose of insulin during the day. To receive more insulin the user pulls off a tab on the patch. In the future researchers are looking at delivering insulin through the pulmonary system using a powder and an inhaler. Eli Lilly has just started a project with Dora Pharmaceuticals to research this alternative delivery system.