Oil-in-water emulsion lotion providing controlled release using 2-methacryloyloxyethyl phosphorylcholine n-butyl methacrylate copolymer as emulsifier.

Lotion is a useful vehicle for active ingredients used to treat skin disease because it can be applied to the scalp, can cover large areas of skin, and it is easy to spread due to low viscosity. An emulsion lotion (EL) containing 2-methacryloyloxyethyl phosphorylcholine n-butyl methacrylate copolymer (PMB) as an emulsifier that provides controlled-release was developed. Diphenhydramine (DPH) was used as a model drug. Formulation with 5% DPH, 5% soybean oil, and 4% PMB in water was emulsified using a high-pressure homogenizer. Polysorbate 80 (TO) was used instead of PMB for comparison. They were applied in vitro to Yucatan micropig intact or stripped skin at a practical dose (2 μL/cm(2)). For stripped skin, penetration of DPH from 4% PMB EL was slower than that from 1% TO EL; results for intact skin were similar. The same phenomenon was observed with application to rabbit skin in vivo. When 4% PMB EL dried on the skin, it made a thin film matrix incorporating the oil phase, which controlled the release of DPH. The release rate could be controlled by the ratio of oil phase to PMB. The EL with PMB shows promise as a vehicle for long-acting treatment of skin diseases.