07/2016, Finished R&D Projects

Development of a process for the incorporation of urea into an ointment base for the development of a keratolytic

  • funding program: ZIM-KF (BMWi)
  • term: 01.03.2016 – 28.02.2018
  • project partners:

Pharmazeutische Kontroll- und Herstellungslabor GmbH (PKH)
Otto-von-Guericke-Universität Magdeburg (OvGU)

Initial position:

Urea is one of the most important prescription drugs. Urea is hygroscopic and therefore complicated in storage and handling. The use in water-containing formulations is unproblematic since urea dissolves readily in water. In contrast, the use in water-free systems is difficult.

So far, the urea is rubbed for comminution with mortar and pestle under acetone directly in the pharmacies and then incorporated into the ointment base. This is time consuming and does not guarantee that no sensible particles are contained.


The task is to develop a water-free urea ointment and a process in which the urea with a particle size <60 μm is incorporated into the ointment base in the highest possible concentration. For this purpose, a W/O-emulsion shall be prepared at PPM, which afterwards will be dried at Otto von Guericke University Magdeburg to obtain a water-free formulation.


It was possible to produce an emulsion according to specifications by means of ultrasonic membrane technology in a continuous process. The most stable formulation was found to be yellow vaseline and a urea solution in the ratio of 30% oil to 70% aqueous phase. The droplets show a very narrow size distribution within the desired range. The method is currently not suitable for the production of larger amounts.

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