Foto del docente

Roberto Gotti

Associate Professor

Department of Pharmacy and Biotechnology

Academic discipline: CHEM-07/A Pharmaceutical Chemistry

Research

Keywords: chiral separation validation of analytical methods capillary electrophoresis chromatographic analysis sample preparation analysis of therapeutic proteins paper-based microfluidics

The research area is in the field of pharmaceutical analysis and in particular it concerns the development and application of chromatographic techniques (HPLC and GC-MS) and capillary electrophoresis (CE) in analysis of bioactive compounds.

The specific subjects of research are:
1) Development and application of electrokinetic systems based on complex pseudostationary phases (mixed micelle, micelle-cyclodextrin, microemulsions, proteins).
2) Development and application of capillary isoelectric focusing for characterization of therapeutic proteins (in particular monoclonal antibodies). 
3) Microfluidic paper-based analytical device

1. Development and application of electrokinetic systems based on complex pseudostationary phases.
Improved separation selectivity in electrokinetic systems can be achieved by supplementing the electrophoretic running buffer with additives able to establish reversible interactions with the solutes to be separated. Among the additives, surfactants are very successful; they are used at concentration higher the critical micelle concentration (cmc). Under these condition a micellar pseudostationary phase is obtained. In this field the research activity has been addressed to the development of new micellar systems based on mixed micelle (from different surfactants) such as sodium dodecyl sulfate (SDS) and bile salts. Further, the role of cyclodextrins as chiral additives in electrokinetic systems has been considered. Finally, microemulsion based on oils such as heptane and octane in the presence of surfactants and co-surfactants, have been applied as separation pseudostationary phases. The possible role of the components of the considered pseudostationaty phases can be hypothesized by means of the evaluation of characteristic chromatographic parameters such as selectivity, resolution, capacity factor, and efficiency; furthermore, also physico-chemical parameters such as zeta potential, ionic radius of the micelle aggregates, inclusion/complexation constants and kinetic constants can be determinated in order to characterize the complex systems.
The use of proteins as additives to the running buffer belongs to this research field; proteins can be considered as useful chiral selectors.
In general the development of all of these described complex systems can be advantageously carried out by means of chemometric and Quality by Design approaches: this part of the research activity is in collaboration with a team of the University of Florence. The proposed CE systems allowed to achieve interesting and useful methods for related substances analysis in pharmaceuticals.
2. Capillary isoelectricfocusing (CiEF)
CiEF is developed and applied to study and characterize the charge variants of therapeutic proteins and in particular of monoclonal antibodies, allowing the determination of the isoelectric points of the charge variants. This characterization is of fundamental importance in the quality control of biotechnological drugs.
3. The fabrication of microfluidic chips can be achieved using chromatographic paper. By employing a wax printer, hydrophobic boundaries can be defined for channels, allowing for fluid flow regulated by capillary action thus avoiding external pumps. The resulting devices, known as microfluidic paper-based analytical devices (µPADs), are used as platforms for reactions that enable the colorimetric detection of various analytes of interest whose quantitation can be achieved by scanning using a smartphone. Since the movement of fluid within the paper-based microfluidic channels of the device is correlated with its architecture, it's essential to dimensionally optimize the device prior to its utilization. In this research line, the Analytical Quality by Design (AQbD) approach is adopted for this optimization purpose.