Formulation of Modified Microspheres Based on Cyclodextrin-Lactic Acid Polymers

Polymers, based on Poly L-lactic acid (L-PLA) and coupled with b-Cyclodextrin (b-CD), have been used for the preparation of microspheres for drug encapsulation. The strategy was based on the modification of the terminal carboxylic group of L-PLA (73.000) by coupling it with a b-CD in the presence of the peptide coupling agents: DCC/HOBT. The degree of functionalisation was found to be 80%. Characterizations of the new product were carried out using 1H NMR, gel permeation chromatography, and acid base titration. The size of the functionalized microspheres was determined to be 211 µm by Dynamic Light Scattering (DLS). Amphotericin B (AmB), a polyenic antifungal molecule, has been incorporated in L-PLA coupled with b-CD microspheres. The maximal quantity of AmB encapsulated, reported to 100 mg of the microspheres, was 7.2 mg (encapsulation ratio 60% by mol).