Electrospun scaffolds of amphiphilic PLLA, PEO and PPO blocks copolymers as drug carriers

L. M. D. LOIOLA ; P. R. CORTEZ TORNELLO; G.A. ABRAHAM; M. I. FELISBERTI

Dresden

Conferencia; European Polymer Conference, Dresden 2015; 2015

European Polymer Federation

Electrospun polymeric scaffolds are very attractive for many biomedical applications. By adjusting the component ratio of block copolymers, properties of electrospun matrices can be tailored with desired functions. Further, amphiphilic copolymers can encapsulate drug molecules and electrospun membranes can be used for drug release in a controlled manner. [1] In the present work, L-lactide was copolymerized with poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) as hydrophilic comonomers to obtain biodegradable amphiphilic block copolymers. Fibrous scaffolds of such copolymers were prepared by electrospinning. The electrospun membranes were used as carriers for both hydrophilic and hydrophobic model drugs. Beaded fibrous structures were observed by scanning electron microscopy. X-ray diffraction and differential scanning calorimetry analyzes showed the crystallinity suppression of loaded model drugs and the presence of two distinct phases: an amorphous PEO/PPO phase and a major crystalline PLLA phase. The drug distribution was elucidated by the combination of dynamic mechanical analysis (DMA) and confocal Raman spectroscopy. The effect of the hydrophobic drug on the thermal properties of electrospun membranes, as investigated by DMA, indicated that loss modulus curves were similar to those observed in neat membranes, presenting a single and large glass transition (Tg ~ -15°C). However, the presence of the hydrophilic drug led to two distinct Tg related to PEO/PPO (-45°C) and PLLA (50°C) amorphous phases. The mapping of both drugs and copolymers characteristic Raman signals revealed that the hydrophilic drug was mainly located within the PEO/PPO-rich beaded structure, whereas the hydrophobic drug was homogenously dispersed in the membrane structure. As the drug release behavior can be modified by altering the fiber morphology, copolymer hydrophilicity ratio and drug loading, in vitro drug release kinetics are currently being investigated.