Search

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., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Precipitation of bovine serum albumin (BSA) by anionic surfactants with alkyl chains of increasing lengths (octyl, decyl, dodecyl sulfates) was studied at room temperature, at pH 3.0, in isotonic sodium chloride solution. The particle size of albumin, the zeta potential, the surface charge and fluorescent properties of BSA-surfactant composites were investigated concerning addition of increasing amount of surfactant. The thermal stability of the systems was monitored by calorimetric analysis (DSC). The formation of the well-ordered structure in the self-assembly process in liquid phase was studied by XRD measurement. The structure of the precipitated BSA-surfactant nanocomposites was characterized by small-angle X-ray scattering (SAXS). Finally, ibuprofen (IBU) molecules were enclosed in BSA-surfactant bioconjugate systems and the release properties of the drug were investigated. It has been found out that, as a consequence to the increasing number of carbon atoms in the alkyl chains of the surfactant, the structure and the fluorescent properties of the aggregates formed can be controlled due to the increase in the hydrophobicity of BSA-surfactant composites. The bioconjugates are well applicable as carrier to realize controlled release of drug molecules., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Bovine serum albumin (BSA) based core-shell nanoparticles were developed as carrier systems for drug transportation. At pH=3, the oppositely charged polyelectrolytes: poly(sodium-4-styrene)sulphonate (PSS) and the chitosan (Chit) bind to the positively charged protein via electrostatic interactions. We applied ibuprofen (IBU) as model molecule which has low solubility. The changes in the BSA's secondary structure during the steps of the synthesis were inspected by FT-IR measurements. The size and the zeta potential were determined by dynamic light scattering (DLS). The changes in the structure and in the size were investigated by small angle X-ray scattering (SAXS) too, for each composite. The release of the ibuprofen was studied by vertical diffusion cell (Franz cell) at pH 7.4 at 25 and 37.5°C. The structure of the core-shell nanoparticles have significantly changed as the pH has risen from 3.0 to 7.4. Kinetic models were used to describe the release mechanism. The experimental results demonstrated that the BSA has an ordered structure at pH=3 which will become random coil by adding ibuprofen. The first shell restores the ordered structure of the protein. The controlled release was carried out; the IBU release decreased by 40% in the case of two-layered composites compared with the "naked" BSA., (Copyright © 2014 Elsevier B.V. All rights reserved.)