Beta-cyclodextrin – Citric acid complexation by ball milling and annealing

In the present study Beta-cyclodextrin (β-CD) and Citric acid (CA) molecules were shown to interact by both ball milling (BM) and annealing treatments. Thermal and structural properties of the resulting complexes formed at different conditions were characterized. Applying theoretical modelling (quantum calculations) the β-CD/CA interaction was confirmed and the binding sides were determined. During ball milling at room temperature citric acid was found to be located inside the β-CD cavity, accompanied by partial cyclodextrin dehydration. The results obtained provide an answer to the question what the binding mechanism of the β-CD/CA molecules is, having a determining bearing on the potential application of the formed complexes.