Developing a Commercial Air Ultrasonic Ceramic Transducer to Transdermal Insulin Delivery

Abstract

The application of low-frequency ultrasound for transdermal delivery of insulin is of particular public interest due to the increasing problem of diabetes. The purpose of this research was to develop an air ultrasonic ceramic transducer for transdermal insulin delivery and evaluate the possibility of applying a new portable and low-cost device for transdermal insulin delivery. Twenty-four rats were divided into four groups with six rats in each group: one control group and three experimental groups. Control group (C) did not receive any ultrasound exposure or insulin (untreated group). The second group (T1 ) was treated with subcutaneous insulin (Humulin® R, rDNA U-100, Eli Lilly and Co., Indianapolis, IN) injection (0.25 U/Kg). The third group (T2 ) topically received insulin, and the fourth group (T3 ) received insulin with ultrasound waves. All the rats were anesthetized by intraperitoneal injection of ketamin hydrochloride and xylazine hydrochloride. Blood samples were collected after anesthesia to obtain a baseline glucose level. Additional blood samples were taken every 15 min in the whole 90 min experiment. In order for comparison with changes in blood glucose levels, the data were corrected by subtracting the baseline glucose for each rat from each blood glucose level at any time. The statistical multiple comparison (two-sided Tukey) test showed a signifi cant difference between transdermal insulin delivery group (T2 ) and subcutaneous insulin injection group (T1 ) during 90 min experiment (P = 0.018). In addition, the difference between transdermal insulin delivery group (T2) and ultrasonic transdermal insulin delivery group (T3) was signifi cant (P = 0.001). Results of this study demonstrated that the produced low-frequency ultrasound from this device enhanced the transdermal delivery of insulin across hairless rat skin.