Enhancing the hydrophilicity of poly(lactic-co-glycolic acid) with serum albumin by creating colloidal drug carriers

Serum protein/copolymer-based nanosized carrier particles with tunable hydrophilic feature was created by a simple preparation method involving the combination of bovine serum albumin (BSA) and poly(lactic-co-glycolic acid) (PLGA). Maintaining the biocompatible nature of the macromolecules, the use of highly toxic solvents was eliminated and a non-ionic surfactant consisting of a natural vitamin E derivative (TPGS) is utilized as stabilizing agent, whose unique triple role is highlighted. In addition to stabilizing the carrier particles, it also functions as an active vitamin E agent and promotes the encapsulation of vitamin D-3 as well by solubilization. Both the BSA-TPGS and the BSA-PLGA interactions have been quantitatively characterized for the first time using several physicochemical and colloid chemistry techniques to produce the nanoscale structure in aqueous medium. The critical micelle concentration (cmc) and the endotherm enthalpy change (Delta H-mic= 12.45 +/- 0.81 kJ mol(-1)) of the formation of TPGS micelles determined by isothermal titration calorimetry (ITC) was presented as a new data. The prepared nanosized structure has similar to 200 nm in size with no core-shell structure and the contact angle studies clearly confirm the increasing hydrophilic character of the carriers by the presence of protein and systematic change in the PLGA copolymer ratio. Hydrophobic drug loading can also be controlled by using this combined structure.