Endocrine Abstracts

The tight glycaemic control in type 1 diabetes which requires uncomfortable multiple insulin injections is associated with patients’ non-compliance. Therefore, methods which can sustain therapeutic controlled insulin release into the blood based on topical applications may be beneficial with glycaemic control. Accordingly, the present study investigated whether topically applied pectin insulin (PI) amidated matrix patch sustains insulin release into the bloodstream and control some selected deranged metabolic parameters in experimental diabetes. PI patches were prepared by dissolving pectin/insulin in deionised water with subsequent solidification with CaCl₂. Oral glucose tolerance (OGT) responses were evaluated in groups of streptozotocin (STZ)-induced diabetic rats given a glucose load (0.86 g/kg) after an 18 h fast followed by topical application of PI patches containing various insulin doses (2.47, 3.99, 9.57, and 16.80 μg/kg). Short-term (5 weeks) effects were assessed in animals applied thrice daily with topical PI (16.80 μg/kg) 8 h apart. Animals treated with drug-free pectin and insulin (175 μg/kg, s.c.) acted as untreated and treated positive controls, respectively. Blood samples and tissue samples were collected for the measurement of selected biochemical parameters and effects on the expression of insulin-stimulated enzymes and facilitative glucose transporters. OGT responses to PI patches exhibited lower blood glucose levels compared to untreated animals. Plasma insulin concentrations increased significantly following PI patch application with the highest dose eliciting the highest insulin levels by comparison with the lowest dose (4.52±0.27 vs 7.13±0.09 ng/ml). The transdermal PI treatment restored the reduced glycogen concentrations, expression of insulin-stimulated enzymes and facilitative glucose transporters in muscle and hepatic tissues observed in diabetic animals to near normalcy after 5 weeks. We suggest that transdermal PI delivers insulin into the bloodstream with concomitant amelioration of some metabolic parameters suggesting that the formulation may free diabetic patients from multiple insulin injections thereby improving patient compliance.