Beads made of alpha-cyclodextrin and vegetable oils: oil composition and physicochemical properties influence bead feasibility and properties

Beads made of alpha-cyclodextrin and soybean oil are an efficient system for the encapsulation of lipophilic drugs. In this work we investigated the impact of vegetable oil composition and physicochemical properties on bead feasibility and properties. Vegetable oils used in the formulation of dermatological medicines were selected. Beads were successfully formed using wheat germ and sweet almond oils. The oils which could be formulated as beads had low acid value and contained at least 99 % of triglycerides. Bead yield, crystalline organization and rheological behavior of these formulations were similar. Beads formed from soybean oil were larger than those from wheat germ and sweet almond oils due to some traces of triglyceride degradation products. Borage oil led only to a fluid mixture which did not evolve into beads. The acid value of this oil was high and total triglyceride content was 68 % demonstrating the presence of a significant amount of triglyceride degradation products. The rheological behavior and X-ray diffraction pattern of the borage oil-based formulation were different from the other oils. Beads can be successfully prepared with various vegetable oils without modifying the conditions optimized with soybean oil. However, triglyceride degradation products can either increase bead size or prevent their formation.