Determination of the Solubility of p-Coumaric Acid (p-CA) in Different Oils for the Production of Nanostructured Systems: Pre-formulation Studies

Abstract

Introduction: p-Coumaric acid (p-CA), a natural phenolic compound, demonstrates great therapeutic potential with antioxidant, anti-inflammatory, anticancer, and antimicrobial activities. However, its clinical application is limited by low water solubility and reduced bioavailability. Nanotechnology emerges as a solution, enabling the encapsulation of p-CA in nanoparticles to enhance its stability and targeting capabilities. Studies predict its use as an adjuvant in the treatment of neurodegenerative diseases, diabetes, cancer, and microbial infections, including multidrug-resistant strains. Objective: This study aimed to analytically validate a spectrophotometric method for quantifying the solubility of p-CA in various oils, to establish a reliable methodology for future studies on the therapeutic application of p-CA and the development of nanotechnology formulations. Methodology: The methodology involved determining the maximum wavelength (λmax) of 310 nm by spectrophotometry and preparing standard solutions (SP) to ensure a linear absorbance according to the Beer-Lambert Law. The solubility tests of p-CA were performed in oils such as isopropyl palmitate (PI), dicaprylyl carbonate (CC), benzyl alkylate (C12-14) (AB), isohexadecane (IH), caprylic acid triglycerides (TG), and oleic acid (AO). The samples were kept in contact with the oils under stirring for 72 hours and analysed by calculating the dissolved concentration by the molar absorptivity (ε). Results: The results revealed that AO and TG were the most effective oils in solubilising p-CA, while isohexadecane demonstrated low solubility. The variation in molar absorptivity and standard deviations (SD and RSD) confirmed the influence of oil polarity on solubilization and analytical precision. Conclusion: The developed methodology proved to be sustainable and efficient, validating a pathway to optimise p-CA formulations for safer and more effective therapeutic applications.