Univ.-Prof. Mag. Dr. Ulrich J. Griesser
Preformulation and Polymorphism
The group studies material science aspects of drugs and excipients and their impact on the manufacture and quality of dosage forms. These research and development steps, summarised under the term preformulation, form the basis of modern drug development and enable the rational design of drug manufacturing processes and the optimisation of active ingredient properties in terms of stability, safety and efficacy. The focus is on gathering in-depth scientific information about small active ingredient molecules, which make up the majority of all medicinal products and are processed in a solid, usually crystalline form. This requires a series of analyses of the active ingredient to understand its physico-chemical and structural properties and to predict their influence on the subsequent dosage form.
Comprehensive experimental characterisation of solid-state properties and phenomena provides the basis for innovative optimisation strategies and new insights that are critical to the entire drug development process. This requires extensive systematic investigations and appropriate analytical methodology. The focus is on crystallisation experiments from solvent, melt or gas phase, where new polymorphic forms with the same composition but different crystal structures or solvent adducts are discovered for almost all active ingredients. The selection of the most suitable solid form for further development or the design of strategies to improve solubility and stability as well as processing properties is based on experimental data supplemented by computational methods. One successful strategy is the production of cocrystals, in which the active ingredient is combined with a biologically inactive excipient to form a new crystal form with, for example, improved solubility properties.
Many drugs form hydrates, i.e. they can incorporate water into their crystal structure, which can be more or less strongly bound. If the water is removed by drying processes, the physical properties (e.g. water solubility) and often the chemical stability of the active ingredient change. The characterisation and control of hydrate formation is therefore an essential part of pharmaceutical product development today. The group specialises in the development of methods for the investigation of water-solid interactions and the elucidation of the structural and thermodynamic principles of hydrate formation.
Most drugs are processed into tablets by applying pressure. In recent decades, however, research has increasingly focused on 3D printing technologies as a potential alternative to tablet manufacturing. One contribution from our group is the development of pharmaceutical excipients that solidify without pressure simply by adding a few drops of water. This type of ‘water-soluble gypsumr’ enables both a significantly faster production of tablets using 3D powder printing and the pressureless production of pharmaceutical mouldings directly in blister packs.