Controlled Release of the Anti-cancer Drug Paclitaxel from Bioresorbable Poly(ester-ether-ester) Microspheres

The release of the anti-cancer drug paclitaxel (PTX) from microspheres of the bioresorbable poly(ε-caprolactoneoxyethylene-ε-caprolactone) tri-block copolymer was studied. The microspheres, both loaded and not with PTX, were prepared by emulsion-evaporation technique, then characterized by SEM, AFM, total reflection and spotlight FT-IR spectroscopy, and DSC. The quantities of PTX released were measured by HPLC. The results showed a slow and very regular release, which fits very well the Peppas equation, Mt/M∞ = k · t, where Mt is the amount of solute released at the time t, M∞ is the amount of drug released at the plateau condition, k represents the Peppas kinetic constant and n the diffusion order. Key-Words: Poly(ester-ether-ester), Paclitaxel, Microspheres, Bioresorbable Material, Characterization, Controlled Release