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Purpose: The aim of this study was to optimize the minoxidil (Mx) liposome / ethosome formulations obtained by mechanical dispersion method. The (statistical) design of experiments (DOE) is an efficient procedure for planning experiments so that the data obtained can be analized to yield valid and objective conclusions. Taguchi method uses the signal-to-noise (SN) ratio, which is directly transformed from the quadratic quality loss function, as a measure to determine the robustness of a process. Methods: The effects of membrane composition, liposome size, amount of drug and number of vortexing cycles on the efficacy entrapment were studied in a 25 complete factorial design, made up of 32 runs. Based on the results from the factorial design, a new design was applied to find the optimum condition and to analyse how sensitive the reponse were to variations in the settings of the experimental variables. The SN ratio (h) was used to estimate the quality variation. The variability characteristic is inversely proportional to the SN ratio, so the larger the h is, the more robust is the system. Results: Cholesterol, ethanol and the amount of drug exerted statistical significance, while number of vortexing cycles and time did not. The optimization study carried out leaded to a ethosomal system with a high content in cholesterol. Conclusion: Experimental and Taguchi designs are two valid strategies to improve formulations of liposomes and ethosomes by optimizing the composition of the vesicles and reaction conditions. Cholesterol and ethanol constitute the most importants factors that provide high stability, flux properties and entrapment efficacy of Mx. |
