[Effects of surfactant and solvent on the encapsulation efficiency and size in using double emulsion method for preparing bovine hemoglobin loaded nanoparticles as blood substitutes].

On the basis of previous researches, we have prepared Bovine hemoglobin-loaded nanoparticles (HbP), using the double emulsion method. More mild dispersing treatment was employed during the primary and secondary emulsion; over 97% encapsulation efficiency (EE%) and an average size about 286 nm were achieved by using surfactants, screening solvents, as well as avoiding the traditional strong dispersing process. The value of Hydrophile-lipophile balance in oil phase exerted a significant effect on EE% and led to higher EE% when matched with the surfactants in outer aqueous phase. When compared with the sole solvent Span80, the mixed surfactants such as Poloxemer188/Span80 stabilized the emulsion more efficiently and increased the EE%. The higher concentration of surfactants resulted in higher EE% and narrower size distribution. But over some amount, the surfactants had no significant effect on EE%, resulting in larger size and polydispersity index (PDI). The appropriate removal rate of solvents contributes to higher EE%, smaller size and PDI.