Emeritus Professor Mino R Caira
(Director, Centre for Supramolecular Chemistry Research)
Professor of Physical Chemistry. BSc Honours (1970), MSc (1971), PhD (1975), University of Cape Town. Lecturer, Senior Lecturer, Associate Professor, University of Port Elizabeth (1976-1988). Post-Doctoral Fellowship, Texas Christian University, Fort Worth, TX (1983). Associate Professor at UCT (1988 - 2001), Professor (2002 - 2009), Professor of Physical Chemistry (2010-present).
My research focuses on the supramolecular modification of pharmaceutically relevant materials (active pharmaceutical ingredients or APIs, as well as excipients) for the purpose of altering their physical properties to facilitate drug processing and drug delivery. A given drug molecule can generally be transformed in the laboratory into a variety of supramolecular entitites such as polymorphs (different crystalline forms/’supramolecular isomers’), solvates (containing both the API and solvent molecules in the same crystal), co-crystals (new supramolecules comprising at least one API and a partner molecule linked to it by non-covalent bonds), and inclusion complexes (of the API with a physiologically acceptable carrier molecule, e.g. a cyclodextrin). Each novel form of a drug has unique physicochemical properties, so this approach of generating novel entities has potential for (inter alia) improving drug stability, controlling the drug release rate, rendering the drug product more easily tablettable, and reducing adverse side effects. Beneficiation of this kind also leads to patentable products.
Techniques that are used in this research include powder and single crystal X-ray diffraction (to determine detailed solid-state structures of the new drug forms), thermal analysis (for quantifying their phase changes on heating, determining thermodynamic stability) and FTIR/Raman spectroscopy (to observe spectral changes following supramolecular modification of the drug). To investigate the thermodynamics of drug complexation in solution (for cyclodextrin complexes in particular), both high-resolution NMR spectroscopy and isothermal titration calorimetry are employed. Solubility properties are assessed from dissolution rate data.
Compounds under investigation include both well-established medicinal agents and new drug candidates. While the methodology employed and the approach to this research is the same for drugs in any therapeutic class, currently there is a strong focus on agents with antitubercular, antimalarial, antibiotic, anticancer and anti-HIV activities. Because of its applied nature, there is strong interest in this research from pharmaceutical companies. Several projects are undertaken in collaboration with scientists at prominent pharmacy schools and research institutions in Europe and the USA. A related on-going project of current interest is the beneficiation of antioxidants and agrochemicals (pesticides, herbicides) through their inclusion in cyclodextrin molecules. These are being investigated in collaboration with scientists in Argentina and Romania.