Diversity and Functionality of Excipients for Micro/Nanosized Drug Carriers

Abstract

Continuous efforts to improve performance of drugs via incorporation in particulate and soft colloidal carriers have introduced new functional categories of excipients. These excipients are used to protect drugs, modify their release, and increase their bioavailability and/or selectivity for target tissues with the aim to improve patient compliance, and therapeutic outcomes. Structural and physicochemical variability of these materials may affect their functionality in the final formulation. Therefore, it is of great importance to identify, evaluate, and control physical or chemical characteristics of excipients that are important for their intended use. These characteristics are known as functionality-related characteristics of excipients.This chapter gives an overview of characteristics and variability of the three distinct groups of excipients commonly used for preparation of particulate and soft colloidal carriers: biodegradable polymeric materials, silica-based materials, and natural surfactants. Special attention is paid to functionality, functionality-related characteristics, and functionalization of these materials in relation to their use for preparation of micro/nanosized drug carriers.