Topical treatment (part two): Vehicles, nature and functions

Abstract

Vehicles of topical medicines support the treatment with their physical effects, in addition to their carrying function. Different types of vehicles are composed of various mixtures of three main elements: water (hydrophilic bases), oil and powder. If a vehicle includes only one element, it is called monophasic, if two, biphasic, and if more than two, then it is termed polyphasic. According to the type of utilization, they may be classified as "liquids, semisolids and solids". Liquids are solutions (monophasic-hydrophilic), colloids (in classic type monophasic), suspensions (biphasic), liquid oils (monophasic), liniments (biphasic) and liquid emulsions (W/O-O/W). Semisolids including creams, ointments (pomades), pastes, foams and seras is the most commonly used group. All semisolids are biphasic or polyphasic except for some ointments which are pure semisolid oil (such as petrolatum). The group of solids includes only powdei's which are very bad vehicle and used only for prophylaxis. (Turkderm 2012; 46: 175-80)