Development of a Spectrophotometric Method for Quantification of Carvacrol in Nanoemulsions

Carvacrol has shown antimicrobial activity against a wide range of Gram-positive and Gram-negative bacteria. However, its hydrophobic nature, volatility, and susceptibility to oxidation mediated by light or heat limit its use. Nanoencapsulation provides a protective barrier against degradation and volatilization processes and improves the dispersibility of bioactive compounds. A simple, rapid, and sensitive analytical method was developed and validated by UV spectrophotometry to quantify carvacrol in a nanoemulsion obtained by self-nanoemulsification, using acetonitrile as a solvent to recover the analyte from the nanoemulsion. The UV scanning spectrum of carvacrol (240–300 nm) in acetonitrile showed maximum absorbance at wavelength 275 nm, typical of this monoterpene. The calibration curve was linear from 15 to 65 μg/ml, with a determination coefficient of 0.999. The detection and quantification limits found were 1.6455 and 4.9863 μg/ml, respectively. The validation results confirmed that the method developed is specific, linear, accurate, and precise and it can be successfully applied for the determination of encapsulation efficiency and the content of carvacrol present in a nanoemulsion. Graphical abstract