Abstract

Investigation of Semisolid Pharmaceutical Preparations

The investigation of semisolid pharmaceutical preparations is challenging for analysts due to their complex composition. In general, a prerequisite to quantify active pharmaceutical ingredients as well as impurities is the separation of these chemical entities from matrix compounds. Regarding semisolid preparations, this can be a difficult task, however. The complete isolation of analytes is disturbed by adsorption to matrix components, by insufficient distribution of lipophilic analytes between solvents and samples and by coextraction of matrix components. Also, emulsifiers may interfere with separation procedures. In fact, even test procedures supplied by marketing authorization holders in some cases proved to be less robust. The scientific literature contains only a limited pool of publications dealing with the investigation of semisolid pharmaceutical preparations which can be used to give assistance in complex analytical problems.

This article provides an overview of recurrent analytical complicacies in the investigation of semisolid preparations as usually seen in an Official Medicines Control Laboratory and tries to highlight some approaches to typical topics. Ultrasound treatment, sufficiently long lasting extraction times or complete dissolution of samples in appropriate solvents help to achieve reasonable results. In some cases, Normal Phase HPLC may provide an alternative principle of separation leading to reliable analytical results.

Korrespondenz:

Dr. Nicholas Schramek, Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Sachgebiet Pharmazie, Veterinärstr. 2, 85764 Oberschleißheim (Germany); e-mail: nicholas.schramek@lgl.bayern.de