ABSTRACT
The term macroemulsion is sometimes employed to distinguish the ordinary emulsions defined from microemulsions, nanoemulsions, and micellar systems. Emulsion formulations can be used orally, parenterally, ophthalmically, or topically, and they can be used by respiratory route. Nanoemulsions contain oil phases, surfactants or emulsifiers, active pharmaceutical ingredients, and additives. Many oils, in particular, those of vegetable origin, are liable to auto-oxidation, and their use in pharmaceutical formulations requires the addition of an antioxidant. The advantages of formulating various lipophilic anti-cancer drugs in submicron oil-in-water (O/W) emulsion are obvious. The oil phase of the emulsion systems can act as a solubilizer for the lipophilic compound. Although nanoemulsions are chiefly seen as vehicles for administering aqueous insoluble drugs, they have more recently received increasing attention as colloidal carriers for targeted delivery of various anticancer drugs, photosensitizers, neutron capture therapy agents, or diagnostic agents.
