The Journal of Drug Targeting publishes papers and reviews on all aspects of drug delivery and targeting for molecular and macromolecular drugs including the design and characterization of carrier systems (whether colloidal, protein or polymeric) for both vitro and/or in vivo applications of these drugs. Papers are not restricted to drugs delivered by way of a carrier, but also include studies on molecular and macromolecular drugs that are designed to target specific cellular or extra-cellular molecules. As such the journal publishes results on the activity, delivery and targeting of therapeutic peptides/proteins and nucleic acids including genes/plasmid DNA, gene silencing nucleic acids (e.g. small interfering (si)RNA, antisense oligonucleotides, ribozymes, DNAzymes), as well as aptamers, mononucleotides and monoclonal antibodies and their conjugates. The diagnostic application of targeting technologies as well as targeted delivery of diagnostic and imaging agents also fall within the scope of the journal. In addition, papers are sought on self-regulating systems, systems responsive to their environment and to external stimuli and those that can produce programmed, pulsed and otherwise complex delivery patterns. The Journal of Drug Targeting also carries papers on the physiological and other biological barriers to delivery and targeting, and means of overcoming the barriers, for example, by penetration enhancers, and covers subjects such as extravasation, diffusion in tumours and target tissues, avoidance of the reticulo-endothelial system, and toxicity testing and licensing of novel delivery systems.