Validation study of the unguator, an apparatus for compounding dermatological preparations.

A study was conducted at the Laboratory of Pharmaceutical Technology, University of Liege, Belgium, of the performance of the Unguator Mixing System, an instrument belonging to a new generation of electronic mortar and pestle apparatus, which was designed to improve pharmaceutical compounding, provide pharmaceutically elegant preparations, and reduce nonproductive time. The goal of this study was to verify that preparations that met the actual quality criteria established by the United States Pharmacopeia, the Therapeutic Compounding Formulary, and the British Pharmacopoeia could be achieved by using the Unguator Mixing System. To achieve this goal, the optimal conditions, such as speed, mixing time, and order of addition of the components, were determined for each of several representative preparations. Two different systems were studied, the Unguator 2000 and the Unguator E/S, and effectiveness of standard and disposable blades was examined. Formulations prepared during the study were tested for appearance, microscopic appearance, and, when judged necessary, uniformity of content. Study results revealed that both models tested were less suitable for preparation of gel bases than for other types bases. Very positive and reproducible results were obtained with compositions containing a low content of active ingredient in hydrophobic ointment or hydrophilic cream. A hydrophobic drug such as clioquinol can be mixed effectively in a hydrophilic carbomer gel with either model, as quantitative assays of different batches showed perfect homogeneity, and microscopic examination found no large agglomerates. Special conditions were required for a material such as benzoyl peroxide which consists of large and hard agglomerates. Salicylic acid hydrophobic 10% ointment can be prepared without any difficulty with both models. Both systems provided full protection for the operator against dust inhalation, since all preparation steps, with the exception of weighing the ingredients, occur in closed containers.