Ointment is evenly spread on the skin, in contrast to creams and solutions

Background The efficacy of topical therapy depends on the patient spreading the topical drug in an even layer to give a standard dose. Ointments are b elieved to be more effective than creams and solutions. Objectives To compare the application and spreading of four different pharm aceutical vehicles. Methods Twenty-nine healthy volunteers applied a fixed amount (0.1 g) of so lution (S), ointment (O), cream (C) and low-viscosity cream (LVC) to the ab dominal skin. Area of spread, skin surface lipids (dependent on formulation ) and changes in skin surface temperature (cooling due to evaporation of fo rmulation water/alcohol) were measured. Results Area of spread: O = C = LVC = S. Skin surface lipids: O > C > LVC > S. Difference in skin surface lipids between centre and periphery: O < C = LVC = S. Cooling: O < C = LVC < S. Conclusions The four formulations were spread to similar areas. The ointmen t was spread evenly in the treated area while the other formulations were u nevenly spread, with a lower dose in the periphery. Creams and solutions ha ve disadvantages as vehicles, as rapid evaporation of formulation water/alc ohol, measured as cooling, influences spread, resulting in an uneven topica l dose within the treated area. In contrast. ointment is evenly spread and is thus a more appropriate formulation. Patients should be instructed to ap ply creams and solutions to multiple sites and to spread them quickly.