Study On The Application Of Sponge Spicule In The Transdermal Delivery Of Insulin

Insulin has been widely used in the treatment of diabetes since its discovery,it is the most effective drug for the treatment of diabetes at present.The insulin treatment is usually performed by subcutaneous injection.Transdermal drug delivery is a treatment method in which drugs are absorbed through the skin into the tissue or further into the blood circulation to achieve the treatment effect.And microneedles is an effective and promising method to promote the percutaneous delivery of insulin in current research.The spicules in sponge has the characteristics of natural origin,easy to preparation,single and stable main chemical composition,small size and sharp tip.Previous studies have found that sponge spicule massage the skin to form a large number of tiny pores on the surface of the skin,while macromolecules that cannot penetrate normal skin can enter the skin through these tiny pores.Therefore,we applied sponge spicule to transdermal delivery of insulin.We selected the Haliclona sp.spicule with the best promoting effect from 5 spicule of different sponges.In the in vitro study of the effect of Haliclona sp.spicule acupuncture on promoting insulin transdermal delivery,the insulin penetration rate of 10 mg spicules could reach 54.841±3.87%within 24 h after skin treatment,it is close to the penetration rate of 63.24±1.09%of the cuticle exfoliated skin.This results showed that the Haliclona sp.spicule had a good ability to promote insulin percutaneous penetration in vitro(n=3).In addition,10 mg Haliclona sp.spicule was used to massage the back skin of rats and then the insulin dosage of administration were 4 U,10 U and 20 U,respectively.The results showed that the blood glucose of diabetic rats decreased at a slow rate within 1-8 h after the administration,and the initial blood glucose could be reduced to 13.7±7.4%,7.0±1.4%and 13.1±6.3%after 8 h.And the insulin administration promoted by spicule could maintain the hypoglycemia of diabetic rats for 12 h without fasting.The percutaneous permeation of insulin assisted by spicules can indeed achieve a good hypoglycemic effect(n=3).The safety study of the skin showed that the spicules only caused slight irritation,and these irritation responses could be recovered within 72 h.It shows that the bone acupuncture has basic safety when used on skin.Although there are still many deficiencies in the preliminary experiment,the way of promoting the transdermal delivery of insulin by spicules is worthy of recognition.This result can pave the way for our future study,and it proves the feasibility and practical significance of spicules in the percutaneous administration.