Drug delivery systems
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Drug delivery systems (DDSs) are polymeric or lipid carrier systems that transport drugs to their targets or receptor sites in a manner that provides their maximum therapeutic activity, prevent their degradation or inactivation during transit to the target site(s).
Drug delivery
systems
Introduction
Drug
delivery systems (DDSs) are polymeric or lipid carrier systems that transport
drugs to their targets or receptor sites in a manner that provides their
maximum therapeutic activity, prevent their degradation or inactiva-tion during
transit to the target site(s), and protect the body from adverse reactions due
to inappropriate disposition. The goal of a DDS is to release the drug(s) to
simultaneously provide maximal safety, effectiveness, and reliability (Figure 14.1). Design of an effective delivery system
requires a thorough understanding of the drug, the disease, and the target
site. Various physicochemical product properties that influence the quality
features of plasma clearance kinetics, tissue distribution, metabolism, and
cellular interactions of a drug can often be controlled by using a delivery
system.
DDSs
can broadly be classified into two groups: macromolecular drug carrier systems
and particulate carrier systems (such as, microspheres, nanospheres, and
liposomes). For site-specific delivery, the drug is released directly into a
specific area, whereas in non-site-specific delivery, the drug is released and
it enters the body systemically. Following administration, tar-geting of drugs
to specific sites in the body can be achieved by linking par-ticulate systems
or macromolecular carriers to monoclonal antibodies or to
Figure 14.1 Objectives of a dosage form or a drug delivery system.
Figure 14.2 Commonly used nanocarriers for drug delivery and targeting.
The ability of a macromolar or
particulate carrier system to deliver a drug to a target site depends on the
following characteristics: molecular weight/size, surface charge, surface
hydrophobicity, and presence of targeting ligands. Figure
14.2 shows com-monly used nanocarriers for drug delivery and targeting.
In
this chapter, various DDSs will be described. Biological events and processes
influencing drug targeting will also be discussed. This chapter will provide
the reader with an insight into the rapid developments in the area of drug
delivery and targeting.
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