Solid-state nanoparticle coated emulsions for encapsulation and improving the chemical stability of all-trans-retinol.
Submicron oil-in-water (o/w) emulsions stabilised with conventional surfactants and silica nanoparticles were prepared and freeze-dried to obtain free-flowing powders with good redispersibility and a three-dimensional porous matrix structure. Solid-state emulsions were characterised for visual appearance, particle size distribution, zeta potential and reconstitution properties after freeze-drying with various sugars and at a range of sugar to oil ratios. Comparative degradation kinetics of all-trans-retinol from freeze-dried and liquid emulsions was investigated as a function of storage temperatures. Optimum stability was observed for silica-coated oleylamine emulsions at 4 °C in their wet state. The half-life of all-trans-retinol was 25.66 and 22.08 weeks for silica incorporation from the oil and water phases respectively. This was ∼4 times higher compared to the equivalent solid-state emulsions with drug half-life of 6.18 and 6.06 weeks at 4 °C. Exceptionally, at a storage temperature of 40 °C, the chemical stability of the drug was 3 times higher in the solid-state compared to the wet emulsions which confirmed that freeze-drying is a promising approach to improve the chemical stability of water-labile compounds provided that the storage conditions are optimised.
Ian Wark Research Institute, The ARC Special Research Centre for Particle and Material Interfaces, Mawson Lakes, Adelaide, SA 5095, Australia.
Nasrin
N
Ghouchi-Eskandar
Spomenka
S
Simovic
Clive A
CA
Prestidge
D002626:Chemistry, Pharmaceutical; D004339:Drug Compounding; D004355:Drug Stability; D004356:Drug Storage; D004655:Emulsions; D005612:Freeze Drying; D006207:Half-Life; D007700:Kinetics; D053758:Nanoparticles; D036103:Nanotechnology; D009821:Oils / Q000737:chemistry; D010316:Particle Size; D011208:Powders; D012822:Silicon Dioxide / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods*; D013696:Temperature; D014801:Vitamin A / Q000737:chemistry*; D014815:Vitamins / Q000737:chemistry*
D004655:Emulsions; D009821:Oils; D011208:Powders; D013501:Surface-Active Agents; D014815:Vitamins; D014801:Vitamin A; D012822:Silicon Dioxide