non-invasive and less degradative ways of insulin administration

Protein and peptide delivery systems attract great attention nowadays. they play crucial role in several diseases, but their way of administration has some disadvantages that makes patients dissatisfied. in this study, we choose insulin as a peptide that is used for type i and type ii diabetic patients, but injection way of its usage is not suitable in diabetes as a chronic remedy. although oral way is a needle-free one, but its bioavailability through that would be decreased because of degradation in gastro-intestine and consequently, further dosage should be used to get the desired hypoglycemic effect. administration of insulin through non-parenteral and less enzymatic pathways, such as intranasal, pulmonary, transdermal, colon and vaginal routes, is new that attracts researchers’ attention considerably. although the bioavailability of insulin may be lower than the current injection way, but it may be improved by some strategies like the use of permeation enhancers. there are also some limitations in each way, but propagation of them would result in improvement of patients’ quality of life and may cause some economic profits. the objective of this review was to introduce the convenient ways for long term insulin administration with few enzymatic barriers.