Electrospinning of polylactide and polycaprolactone mixtures for preparation of materials with tunable drug release properties

Electrospun microfibers with a variable ratio between polycaprolactone and polylactide homopolymers were prepared from chloroform/acetone solutions. Thermal properties of both as-processed and melt crystallized samples were studied. Time-resolved WAXD patterns were taken during heating runs in order to evaluate the initial crystallinity and changes occurred during cold crystallization. DSC and WAXD experiments clearly indicated that fiber orientation facilitated the crystallization of polylactide, especially when fibers had a high polycaprolactone content. Triclosan could be effectively loaded by electrospinning and was well mixed in the polycaprolactone and polylactide phases. SAXS patterns allowed inferring that both polymers were also well mixed in the electrospun fibers and that triclosan hindered the lamellar stacking of polycaprolactone. Thermal properties, crystallinities and fiber surface morphologies were also significantly modified by the incorporation of triclosan. The release of drug loaded samples into different mixtures of ethanol and Sörensen medium was evaluated and the different affinity between triclosan and the two studied homopolymers was demonstrated. In this way, it was possible to obtain a series of materials with tuned release behavior and tuned antibacterial effect. The biocompatibility of all triclosan loaded polymer mixtures was evaluated by studying cell adhesion and proliferation.