Production of copper loaded lipid microparticles by PGSS® (particles from gas satured solutions) process

•Copper nanoparticles were successfully loaded into lipid microparticles by PGSS.•Mixtures with a water content up to 40% were effectively processed.•Microparticles with uniformly distributed metal nanoparticles were produced.•Copper encapsulation efficiency up to 60% was achieved.

Production of lipid particles loaded with metal nanoparticles by supercritical fluids based processes has been barely studied. In this work, copper nanoparticles were loaded into glyceryl palmitostearate microparticles by PGSS® (Particles from Gas Saturated Solutions). The effect of different variables, temperature (60-80 °C), copper load (0.2-5%w/w) and water addition (0-40%w/w), in particle size and encapsulation efficiency has been studied. The dispersion of metal nanoparticles in the lipid has been determined by SEM-FIB coupled with EDS mapping. In all cases, mean particle size values lower than 70 μm have been obtained, and encapsulation efficiencies around 60% have been achieved. The addition of water has no negative effect in encapsulation efficiency nor in nanoparticles dispersion within the lipid microparticle, being important since nanoparticles are commonly synthetized in aqueous medium.

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