Development and optimization of Clinacanthus nutans liquid spray using a two-level full factorial design

This study aimed to develop and optimize a topical Clinacanthus nutans liquid spray that dries quickly after spraying and has low stickiness. An experimental design was adopted to evaluate the effects of the amounts of polyvinylpyrrolidone (X₁) and glycerol (X₂) and the ratio of acetone:ethanol (X₃) on the stickiness (Y₁ ), solution viscosity (Y₂), evaporation rate (Y₃), and spray coverage radius (Y₄) of the solution. Results revealed that all independent factors had a substantial effect on Y₁ -Y₃. In this model, the synergistic effect was uncommon. The optimized formulation consisted of X₁ of 0.1%, X₂ of 1.0%, and X₃ of 59:41. The response values of Y₁, Y₂, Y₃, and Y₄ were 92.24 mN, 4.63 cP, 0.0959%, and 9.40 cm, respectively. The actual results were close to those predicted by the experimental design model. Therefore, the optimized topical spray formulation can be used in actual practice.