Insulin therapy subcutaneous administration

The standard mode of insulin therapy has traditionally been by subcutaneous injection using disposable needles/syringes. However, other routes of administration, including continuous subcutaneous insulin infusion pumps and inhalation of finely powdered aerosolized insulin, are currently being explored. 

F. Role in therapy Limited evidence suggests that better control of postprandial glucose may lead to long-term benefits. Both insulin lispro and insulin aspart, because of their rapid absorption after subcutaneous administration, are effective in this regard, but they have not been compared. 

The standard mode of insulin therapy is subcutaneous injection using conventional disposable needles and syringes. During the last 3 decades, much effort has gone into exploration of other means of administration. 

In some cases, cell surface expression of certain species can be induced for example, interleukin-1 has been shown to induce the biosynthesis and cell surface expression of procoagulant activity in human vascular endothelial cells [197]. Such materials may also be exploitable as candidates for bioadhesion studies. Millions of lives of patients with diabetes have been saved since the introduction of insulin therapy. However, several daily injections of insulin are required to maximize glucose control in diabetic patients. Insulin is administered by subcutaneous injection, but this route of administration has a slow onset and subsequent prolonged duration of action. These limitations show up more when higher doses of insulin are injected, which results in a long duration of action and forces the patients to consume additional amounts of food to limit the risk of hypoglycemia [198]. 

Controlled parenteral delivery of proteins has recently been reviewed by Pitt (1950) and Heller (1993a,b). Developments in insulin delivery systems have been reviewed by Saudek (1993), devices for insulin administration by Selam and Charles (1990), and subcutaneous insulin therapy by Houtzagers (1989), Home and Alberti (1992), Koivisto (1993), and Heine (1993). 

Insulin pump therapy consists of a programmable infusion device that allows for basal infusion of insulin 24 hours daily, as well as bolus administration following meals. As seen in Fig. 40-3, an insulin pump consists of a programmable infusion device with an insulin reservoir. This pump is attached to an infusion set with a small needle that is inserted in subcutaneous tissue in the patient s abdomen, thigh, or arm. Most patients prefer insertion in abdominal tissue because this site provides optimal insulin absorption. Patients should avoid insertion sites along belt lines or in other areas where clothing may cause undue irritation. Infusion sets should be changed every 2 to 3 days to reduce the possibility of infection. 

Drug administration route There is a greater risk of developing ketoacidosis with insulin-pump therapy than with multiple daily insulin injections, because there is always a smaller subcutaneous depot of insulin at any time with the insulin pump. However, in practice, the frequency of ketoacidosis is similar with insulin pump and insulin injections. Insulin-pump therapy can lead to some localised non-serious skin infections at the infusion site. In general, current pumps are robust and reliable, but malfunctions can still occur. [15 ]... 

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