New Materials and Systems for Drug Delivery and Targeting

The range of bioactive substances emerging as potential drug candidates, together with those currently under research and development, continue to provide major challenges for efficient drug delivery and targeting. Various strategies for formulation design using diverse chemicals as formulation excipients are available, and numerous materials are being considered and developed to provide specific fbnctionalities in the design of medicines. A number of approaches to formulation and drug delivery will be discussed at this symposium and this lecture, serving as a general introduction, highlights the need and value of these approaches coupled with the related issues of excipient properties and design. It has been a constant ambition of formulation scientists to optimise drug delivery systems which provide a defined dose, at a chosen rate, at a selected time, to a targeted biological site. Whilst improvements in drug delivery over recent years are impressive, there is still some way to go in filly achieving these objectives. Key issues requiring continuing research and study range from fbndamental understanding of the biosystems and targets and basic characterisation of novel classes of bioactive agents, to the development of ‘designer’ or ‘smart’ materials which provide required excipient or carrier properties to achieve modulated and targeted drug delivery. Coupled with these activities is the necessary realism of the practical constraints imposed in designing drug delivery systems. These include the necessity of using materials which will achieve regulatory approval and clearance, and the constraints imposed by the nature of the various routes of administration available for drug delivery.