Methodological Approaches for the Characterization of the Self-assembling Behaviour in the Pharmaceutical Field

Abstract

Self-assembling is a thermodynamic process in which single components aggregate into large ordered structure as a function of temperature and concentration. Self-assembling has been longer exploited in the pharmaceutical field for the development of colloidal delivery systems for therapeutic, theranostic or preventive medicine purposes. In fact, the design of new polymeric or lipid self-assembling systems represents an advance in material science and nanomedicine, giving rise to a plenty of drug or functional substance carriers as polymeric or surfactants micelles, liposomes, vesicles and biomembranes. Recently, the growing interest in bioresponsive nanomaterials, able to respond to different stimuli in vivo (pH or temperature), has greatly influenced the architecture of these self-assembling systems, leading to the formulation of functionalized, coated, layered or multi-walled colloidal particles. This improvement has definitely made not effortless the chemical-physical characterization of the self-assembling process in the pharmaceutical field. The present chapter is aimed to review the common available techniques employed to characterize the self-assembling behaviour of drug delivery systems in a temperature or concentration dependent manner. A particular focus will be placed on the calorimetric techniques (as differential scanning calorimetry, DSC or isothermal titration calorimetry, ITC), but also on alternative methodologies as high-resolution ultrasonic spectroscopy (HR-US).