Formulation optimization of long-circulating liposomes entrapped with glycyrrhetic acid by Box-Behnken design and response surface methodology

Aim: To optimize the formulation of long-circulating liposomes entrapped with glycyrrhetic acid (GA-LCLP). Methods: GA-LCLP was prepared by the membrane-hydration method. The effects of the factors, such as the amount of soybean lecithin, sodium desoxycholate and PLA-mPEG, on the entrapment efficiency, the diameter, the release rate and the general requirements were evaluated and optimized by Box-Behnken design, which was carried out by the Design-Expert 7.0.3 (Probation Edition). Results: In the optimized GA-LCLP formulation, the entrapment efficiency was (92.67 ± 0.88)%, the diameters was (248.8 ± 20.3) nm, and the release rate was (42.24 ± 3.35)%. Moreover, the deviations of the measured values from the predicted ones were less than 10% (n = 3). Conclusion: Each index of the optimized GA-LCLP formulation was well fitted with the predicted value. Therefore, the adopted model was reasonable and effective. In addition, the physicochemical properties of the optimized GA-LCLP by Box-Behnken design was stable.