Formulation of modified microspheres based on cyclodextrin-lactic acid polymers

Abstract

Polymers, based on Poly L-lactic acid (L-PLA) and coupled with β-Cyclodextrin (β-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 β-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 1 H 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 β-CD microspheres. The maximal quantity of AmB encapsulated, reported to 100 mg of the microspheres, was 7.2 mg (encapsulation ratio 60% by mol).