Positively charged submicron emulsions - a new type of colloidal drug carrier

A positively charged submicron emulsion was prepared and stabilized by forming a mixed film comprising phospholipids, poloxamer and stearylamine at the o/w interface of the oil droplets. This was confirmed concomitantly by the selective adsorption of the thiocyanate anion and the lack of adsorption of Ca²⁺ onto the emulsified oil droplets of the actual emulsions. The incorporation of various drugs in the new type of submicron emulsions altered neither the nature of the surface charge nor the mean droplet size. These results clearly demonstrated that the positively charged submicron emulsion can be used as a new type of colloidal drug carrier.