Size control of poly( d, l-lactide- co-glycolide) and poly( d, l-lactide- co-glycolide)-magnetite nanoparticles synthesized by emulsion evaporation technique

Abstract

Emulsion evaporation method was used to prepare poly(lactide- co-glycolide) (PLGA) nanoparticles with oleic acid stabilized superparamagnetic iron oxide nanoparticles, in the presence of sodium dodecyl sulfate (SDS) as a surfactant. The magnetite nanoparticles, initially obtained as water soluble particles, were surface functionalized with oleic acid to ensure their efficient entrapment in the PLGA matrix. The inclusion of magnetite with oleic acid (MOA) into the PLGA nanoparticles was accomplished in the organic phase. Synthesis was followed by dialysis, performed to eliminate the excess SDS, and lyophilization. The PLGA–magnetite nanoparticles were compared with naked PLGA nanoparticles. Naked PLGA nanoparticles ranged in size from 38.6 to 67.1 nm; when MOA was entrapped in the PLGA matrix, the nanoparticle size ranged from 78.8 to 115.1 nm. The MOA entrapment efficiency varied from 57.4 to 91.9%. The efficiency of SDS removal by dialysis from the nanoparticles varied from 51.0 to 88.8%. SDS concentration played a critical role in controlling the nanoparticle size. A three-fold increaser in the PLGA concentration was possible with the proposed method without increasing the size of the empty PLGA nanoparticles over 100 nm The size and uniformity of the MOA suspension, was found critical in forming small and uniform magnetic–polymeric nanoparticles (M-P NPs).