Galenic Difficulties in Incorporation of Urea into Topical Semi-Solid Vehicles Used in Compounded Prescriptions

Overview

Urea belongs to frequently prescribed pharmaceuticals in topical dermatologic therapy of individually prepared medical preparations. However it is a quite unstable substance. For preparations containing urea it is necessary to choose appropriate pH and to avoid some incompatibilities. The proper galenic processing also depends on the urea concentration and the nature of vehicle base with which urea should be combined. This paper aims to introduce urea characteristics, its basic use in dermatological practice, possibilities of compounding with semi-solid vehicles most often used in combined prescriptions (Synderman, Cutilan, Ambiderman, Cremor neoaquasorb) according to prescribed urea concentrations, and to men tion important incompatibilities and some mistakes in prescriptions.

Key vords:
urea – urea stability – lactate buffer – inclusion into semi-solid vehicles – mistakes in prescriptions