# Optimization of the Conditions of Solid Lipid Nanoparticles (SLN) Synthesis

## TL;DR

This paper optimizes the synthesis of solid lipid nanoparticles for drug delivery, achieving high efficiency and stable properties.

## Contribution

The study introduces closed-loop high-pressure homogenization for SLN synthesis and achieves 99.8% curcumin encapsulation efficiency.

## Key findings

- A 2:1.25 lipid:surfactant ratio was optimal for curcumin incorporation into SLNs.
- Closed-loop homogenization at 300 bar pressure produced stable nanoparticles with desired physicochemical properties.
- Encapsulation efficiency of curcumin reached 99.80% in optimized SLNs.

## Abstract

Solid lipid nanoparticles (SLNs) have been synthesized as potential drug delivery systems. They are classified as solid lipid nanocarriers that can successfully carry both hydrophilic and hydrophobic drugs. SLNs are based on a biocompatible lipid matrix that is enzymatically degraded into natural components found in the human body. Solid lipid nanoparticles are suitable for the incorporation of hydrophobic active ingredients such as curcumin. The study included the optimization of lipid nanoparticle composition, incorporation of the active compound (curcumin), a stability evaluation of the obtained nanocarriers and characterization of their lipid matrix. Through process optimization, a dispersion of solid lipid nanoparticles (solid lipid:surfactant—2:1.25 weight ratio) predisposed to the incorporation of curcumin was developed. The encapsulation efficiency of the active ingredient was determined to be 99.80%. In stability studies, it was found that the most suitable conditions for conducting high-pressure homogenization are 300 bar pressure, three cycles and a closed-loop system. This yields the required values of the physicochemical parameters (a particle size within a 200–450 nm range; a polydispersity index of <30%; and a zeta potential of about |±30 mV|). In this work, closed-loop high-pressure homogenization was used for the first time and compared to the currently preferred open-loop method.