Drug delivery/targeting system

Adamantane derivatives can be employed as carriers for drug delivery and targeting systems. Due to their high lipophUicity, attachment of such groups to drugs with low hydrophobicity could lead to a substantial increase of drug solubihty in lipidic membranes and thus increases of its uptake. 

Some of their derivatives have been used as antiviral drugs. Due to their flexible chemistry, they can be exploited to design drug delivery systems and in molecular nanotechnology. In such systems, they can act as a central lipophilic core and different parts like targeting segments, linkers, spacers, or therapeutic agents can be attached to the said central nucleus. Their central core can be functionalized by peptidic and nucleic acid sequences and also by numerous important biomolecules. 

Notwithstanding the plaints above, the last question must be discussed can a delivery system be used to overcome conditions imposed by the biological system (excluding those posed by the route of administration) to achieve optimized therapy Two major approaches to this end have been proposed regional drug delivery and targeted drug delivery. 

Controlled release, although resulting in a zero-order delivery system, may also incorporate methods to promote localization of the drug at an active site. In some cases, a controlled-release system will not be sustaining, but will be concerned strictly with localization of the drug. Site-specific systems and targeted-delivery systems are the descriptive terms used to denote this type of delivery control. 

Before treating the various classes of sustained- and controlled-release drug-delivery systems in this chapter, it is appropriate to note that drug delivery may be incorporated in other chapters where the various classes of drug products and routes of administration are discussed. In addition, the reader is referred to Chapter 14 on target-oriented drug-delivery systems. 

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