# High-Load Borage Oil Nanoemulsion Development via Polyol-Free D‑Phase Emulsification

## TL;DR

This study develops a safe and stable borage oil nanoemulsion using a novel polyol-free method, suitable for pharmaceutical applications.

## Contribution

A scalable, solvent-free D-phase emulsification method for high-load borage oil nanoemulsions without alkyl polyols.

## Key findings

- Optimized formulations achieved 300–400 nm droplets with narrow size distribution and high zeta potential.
- The method allows up to 50% w/w oil concentration with minimal surfactant use.
- In vivo toxicity tests showed no significant toxicity in Galleria mellonella.

## Abstract

This study presents
the development of borage oil nanoemulsions
using the D-phase emulsification (DPE) method, notably excluding alkyl
polyols. Utilizing polysorbate 80 as the surfactant, the method achieves
high oil concentrations (up to 50% w/w) with minimal surfactant use,
obviating the need for hydrophilic–lipophilic balance adjustments.
A Box–Behnken design analyzed the effects of borage oil, surfactant,
and initial water concentrations on particle size and stability. Initial
water concentration significantly reduced the average hydrodynamic
diameter (AHD), with optimized formulations showing spherical droplets
of 300–400 nm, narrow size distributions (PdI < 0.3), and
robust zeta potential (←20 mV), maintaining physical stability
for 12 months. Microscopy, X-ray diffraction, and thermal analyses
affirmed the amorphous or liquid crystalline state of the formulations.
Scale-up to 1 kg retained similar physicochemical properties. The
in vivo toxicity assessment in the Galleria mellonella model indicated no significant toxicity, highlighting the formulation’s
safety. This scalable, solvent-free approach offers insights into
the influence of key formulation variables, potentially advancing
its application in pharmaceuticals.