Optimal Fabrication of Nano Menthol/PEG Particles by Electrospraying

Background: L-menthol [(1R,3R,4S)-(-)-menthol] is a flavoring that is the main component of mint herb essential oils, especially of the Mentha piperita and Mentha arvensis species. Its low solubility in aqueous systems makes precise formulation necessary in the final products. Of the methods available for fabrication of nanoparticles for use in pharmaceuticals, electrospraying is easy and requires only one step. Objective: Electrospraying was used to fabricate menthol/PEG micro/nanoparticles. The experiments used menthol concentrations of 10%, 15% and 20% (wt) and PEG concentrations of 5%, 10% and 15% (wt). Methods: The effect of menthol and PEG concentration on the morphology of the fabricated particles was investigated using scanning electron microscopy (SEM). Response surface methodology (RSM) was used to determine the best levels for each parameter under optimal conditions. Results: SEM results revealed that an increase in PEG and menthol concentrations in solution, increased the particle diameters. RSM showed that particle diameter should be calculated as the square root of a function of the first order and cubic forms of menthol and PEG. Optimization results show that the optimal menthol concentration is 10.7% (wt) and PEG concentration is 7.31% (wt). The optimal modeled particle diameter of 1219 nm approached the real test particle diameters (1136 nm). The results indicate that the modeled conditions were appropriate for menthol/PEG electrospray particles. Conclusion: The results showed that the maximum PEG concentration effects particle diameter because of its polymeric structure. At high menthol concentrations, the percentage of menthol in a droplet was greater than the PEG concentration and some menthol sublimated during drop formation. At low menthol concentrations, PEG covered the menthol and prevented sublimation, decreasing the effect of menthol concentration.