Three drugs with different hydrophilicity are encapsulated in poly-lactide (PLA) and Poly(lactide-co-glycolide) (PLGA) drug delivery systems prepared by ring-opening polymerization (ROP). Formation of well-defined core-shell type nanoparticles (NPs) is observed for α-tocopherol (TP) and by systematically altering the hydrophilicity of the drug carrier NPs the entrapment efficiency (EE (%)) can be remarkably controlled. The highest (90%) of EE (%) is obtained for the most lipophilic TP from the applied three drugs in the 75% lactide-containing PLGA75 NPs, which is ca. 69% for PLA NPs. Subsequent to drug loading the detailed characterization of the polymers and the formed NPs was carried out. Precipitation titrations reveal that our PLGAs have narrower weight distribution than the commercially available polymer enabling favorable properties to obtain NPs with better size distribution. It is pointed out that during the synthesis the applied solvent and stabilizing agent play a decisive role in the size distribution and stability of the drug carrier NPs. The Pluronic F127-stabilized NPs have the smallest diameter (ca. 190 nm) with less polydispersity among the applied stabilizing agent in nanoprecipitation.
Keywords: Biocompatible polymers; Drug encapsulation; Ketoprofen; PLGA nanoparticles; Tocopherol (vitamin E).
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