Effect of PEG 400 Concentration on the Physicochemical Characteristics and Stability of Avocado Seed Oil Nanoemulsion Hair Spray

This study investigated the impact of PEG 400 concentration on the properties and stability of an avocado seed oil nanoemulsion hair spray, which could potentially reduce hair loss. Three formulations (F1–F3) with varying PEG 400 concentrations (15%, 20%, 25%) were tested. Results showed that increasing PEG 400 decreased pH and viscosity while increasing spreadability. Formula F3 (25% PEG 400) demonstrated the best stability and was characterized by a particle size of 14.6 nm, a polydispersity index of 0.234, and a zeta potential of −4.0 mV. Despite its stability and small droplet size, the low zeta potential suggests that further research is needed to understand its colloidal stability and hair-growth efficacy before it can be used pharmaceutically.