An oil in water microemulsion or sub-micron emulsion composition for dermal delivery of at least one pharmaceutically active ingredient comprising an oil phase dispersed throughout a water phase, said oil phase including at least one of the group consisting of animal, mineral or vegetable oils, silanes, siloxanes, esters, fatty acids, fats, halogen compounds, and alkoxylated alcohols； and at least one lipophilic surfactant； and said water phase including at least one hydrophilic surfactant, water and optionally non-surfactant amphiphilic compound, the weight ratio of the at least one hydrophilic surfactant to the at least one lipophilic surfactant being approximately 9.0:1.0 to 2.0:3.0.
