Investigation of the effects of nanoemulsion formulation containing glycyrrhizin in Streptozotocin-induced diabetic rats

This study aims to prepare and in vitro and in vivo characterize nanoemulsion formulation containing GLY (GLY-NE). Firstly, the NE formulation was prepared and in vitro characterized. Later, the hypoglycemic and antioxidant effects of GLY-NE formulations in STZ-induced diabetic rats were investigated. Also, histopathological evaluation was performed. The droplet sizes of blank NE (B-NE; 110.75 ± 9.60) and GLY-NE (126.44 ± 3.86) were in the nano-size range. Furthermore, PDI values of B-NE and GLY-NE formulations were less than 0.3. The zeta potential values of B-NE and GLY-NE were (−)19.02 ± 1.18 mV and (−) 20.52 ± 0.83 mV, respectively. At the end of the 21st day, comparing the same dose groups administered GLY or GLY-NE, the blood glucose levels of the diabetic rats administered GLY-NE (D-GLY-NE groups) were lower than the diabetic rats administered GLY (D-GLY groups). Furthermore, the blood glucose level of D-GLY-NE (40 mg/kg) was significantly lower than that of D-GLY (40 mg/kg; p < 0.05). Compared with the diabetic control, the serum ALT and AST levels and liver MDA of the diabetic rats treated with GLY or GLY-NE (for all doses) were significantly decreased, while the liver SOD activity and GSH levels were significantly increased (p < 0.05). The NE formulation may be a potential dosage form for oral delivery of GLY.