Image Credits: Africa Studio/shutterstock.com
The structure of lipid nanoparticles is similar to that of nanoemulsions. Typically, the size of nanoparticles varies between 50 and 1000 nm. It is different from nanoemulsions in that the lipid core is in solid state.
The matrix contains solid lipids or combinations of lipids. The solid lipid particle is stabilized against aggregation by adding polymers or surfactants, whereas in the case of nanoemulsions, natural lecithins are preferred. If lipid nanoparticles are meant to be employed as a carrier, the active ingredients are dissolved or finely spread in the lipid matrix.
Preparing Lipid Nanoparticles Using the High-Pressure Hot or Cold Homogenization Process
Lipid nanoparticles can be made through high-pressure homogenization. A hot homogenization method and a cold homogenization method are explained below in Table 1. The scaling-up to the production scale appears to be uncomplicated since high-pressure homogenization is employed in large-scale processing of emulsions and dispersions in many fields.
Table 1. Scheme for the production of lipid nanoparticles by the hot or cold homogenization technique.
||Hot Homogenization Technique
||Cold Homogenization Technique
||Melt lipid; dissolve or solubilize active ingredient in the lipid.
||Disperse melted lipid in hot aqueous surfactant solution.
||Cooling and recrystallization of the active lipid mixture using liquid nitrogen or dry ice.
||Preparation of a pre-emulsion by means of a rotor-stator homogenizer.
||Milling of the active lipid mixture by means of a ball mill or a jet mill.
||High-pressure homogenization above the melting point of the lipid.
||Disperse lipid microparticles in cold aqueous surfactant solution.
||Cooling and recrystallization.
||High-pressure homogenization at or below room temperature.
Benefits of Using Lipid Nanoparticles in Cosmetics
Following are the important features that make lipid nanoparticles attractive for cosmetic use:
- Controlled release of active ingredients
- Enhanced stability of chemically unstable active ingredients
- Enhanced skin hydration and protection through the formation of a film on the skin
- Pigment effect
Incorporating Lipid Nanoparticles into New Cosmetic Products
Unlike nanoemulsions and liposomes, creating completely new products is not needed if one wishes to use lipid nanoparticles. Their excellent physical stability and compatibility with other ingredients enable them to be often added to existing formulations without any trouble.
Since lipid nanoparticles are patent protected across the world as Nanopearls® or Lipopearls®, product exclusivity can be assured when they are used in new products.