Oligonucleotide adsorption on nanoemulsions obtained by spontaneous emulsification.

This paper describes the adsorption of an oligothymidylate (pdT(16)) on nanoemulsions obtained by spontaneous emulsification procedures. Formulations were composed by medium chain triglycerides, egg lecithin, glycerol, water (NE) and stearylamine (NE SA). After optimization of operating conditions, the mean droplet size was smaller than 255 nm. Adsorption isotherms showed a higher amount of pdT(16) adsorbed on cationic NESA (60 mg/g) compared to NE (20 mg/g). pdT(16) adsorption was also evidenced by the inversion of the zeta-potential of NESA (from +50 to -30 mV) and the morphology of oil droplets examined through transmission electron microscopy. The overall results showed the role of electrostatic interactions on the adsorption of pdT(16) on the oil/water interface of nanoemulsions.