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Administrating Insulin and Insulin Analogues

Oral Insulin

Introduction

Many people who are about to start on insulin injections inquire about alternatives to self injection. Insulin therapy has been around for eighty years, yet alternative methods of insulin delivery have been slow to emerge. The reason for this is that insulin is easily broken down by most methods tested and doesn’t really work that well. This page was written in response to the very many enquiries we receive with regard to alternative routes of insulin delivery.

Why are insulin ‘tablets’ not available as yet?

Insulin is a protein which can be digested just like other proteins in the food. The stomach is a very acidic environment and proteins are quickly denatured (rather like milk ‘curdling’). The presence of food will also influence absorption and make a dose less predictable. This is why oral insulin has never been successful.

What can be done to get around this problem?

Modern pharmaceutical technology allows us to enclose drugs in capsules which can get through the stomach barrier without being destroyed.

What oral preparations are in development?

An oral insulin capsule containing insulin crystals, IntesulinR is currently under development by a company called Coremed Inc., (USA). The development of oral insulin is the sole purpose of this company which gives an idea of the ‘difficulty factor’ as well as the prevailing interest. They have been conducting animal studies sine 1994.

Have there been any positive results?

Animal data has shown ‘significant’ glucose lowering efficacy of IntesulinR when administered with food. While these results are certainly of interest there is still a long way to go before we see oral insulin in common use.

Have any human studies been done?

Yes. The preparation was found to be as effective in controlling blood sugars as injectable regular insulin in a small group of people with type 2 diabetes according to a randomized, single-blind study reported in the February 2003 issue of Diabetes Care.

A study or oral insulin, looking at whether oral insulin can prevent the development of type 1 diabetes in those who have evidence of autoimmunity was funded by the National institute of Diabetes and Digestive and Kidney Diseases (USA). The results were disappointing, however to quote the study chair ‘negative findings also provide important scientific answers’.

 

Dr Nishan Wijenaike
Consultant Diabetologist
West Suffolk Diabetes Service
November 2003