Polylactide/poly(ethylene glycol)/polylactide triblock copolymer micelles as carrier for delivery of hydrophilic and hydrophobic drugs: a comparison study

摘要

Tri-block poly(lactide)–poly(ethylene glycol)–poly(lactide) (PLA–PEG–PLA) copolymers were synthesized and self-assembled into micelles in aqueous solution by double emulsion and nanoprecipitation methods. These micelles were loaded by atorvastatin and lisinopril as hydrophobic and hydrophilic model drugs, respectively. The resulting nanostructures were characterized by various techniques. Atomic force microscopy images disclosed that the micelles have spherical structure with the average size of 100?nm. The micelles exhibited high encapsulation efficiency of about 48?±?0.13% and 84?±?0.13 for atorvastatin and lisinopril, respectively. Fourier transform infrared spectroscopy and differential scanning calorimetry confirmed that strong interaction between atorvastatin and copolymer was the major driving force behind drug loading which subsequently lead to more sustained release behavior of corresponding micelles. Whereas, in case of lisinopril there was no evidence for strong interaction between drug and copolymer. The surface adsorption was the main parameter for drug loading which in turn caused the drug to be quick released. Overall, the results indicated that PLA–PEG–PLA micelles can be considered as a promising carrier for both hydrophilic and hydrophobic drugs with different release characteristics.