Formulation and characterisation of beads prepared from natural cyclodextrins and vegetable, mineral or synthetic oils

A continuous external shaking for 2.5 days of a mixture composed of α-cyclodextrin (6%), soybean oil (19.6%) and water (74.4%) resulted in a calibrated lipid carrier namely bead with a high fabrication yield. The purpose of this work was to explore the possibility to substitute α-cyclodextrin by other natural cyclodextrins, i.e. β- and γ-cyclodextrin and then soybean oil by mineral (Primol® 352 and Marcol® 82) or synthetic (Silicon 200® fluid 10, 50 or 100cSt) oils. Beads can be successfully prepared using Marcol® 82 with α-cyclodextrin and Silicon 50 or 100cSt with γ-cyclodextrin. The area inside oil/cyclodextrin/water ternary diagram corresponding to bead occurrence was superior for the Marcol® 82/α-cyclodextrin couple compared to that observed with soybean oil/α-cyclodextrin couple. Only a few ratios of Silicon 50 and 100cSt/γ-cyclodextrin/water led to beads. The combinations which did not induce bead occurrence gave either emulsions, two non-miscible liquids or a solid mixture. Whatever the materials used, beads exhibited similarities: presence of a crystalline organisation and viscoelastic properties. Manufacturing process of paraffin- and silicon-based beads need further optimisation to increase fabrication yield and later on, to take advantages from the high stability of both oils for the formulation of drugs with beads.