Site-directed drug delivery

Pachene, M. J., Belinka, B., and Simon, P. Novel methods for site-directed drug delivery Drug Deliv. Technol. 3(l) 40-45, 2003. 

Another very important site for drug delivery is the central nervous system (CNS). The blood-brain barrier presents a formidable barrier to the effective delivery of most agents to the brain. Interesting work is now advancing in such areas as direct convective delivery of macromolecules (and presumably in the future macromolecular drug carriers) to the spinal cord [238] and even to peripheral nerves [239]. For the interested reader, the delivery of therapeutic molecules into the CNS has also been recently comprehensively reviewed... 

PCI has been shown to increase the biological activity of a large variety of macromolecules and other molecules that do not readily penetrate the plasma membrane (Table 1). PCI has also been shown to enhance the treatment effect of targeted therapeutic macromolecules. These results show that PCI can induce efficient light-directed delivery of macromolecules into the cytosol, indicating that PCI may have a variety of useful applications for site-specific drug delivery, e.g., in gene therapy, vaccination, and cancer treatment. PCI of BLM has recently been approved for a clinical Phase I trial, where several indications have been included. The first patients with head and neck cancer have recently been treated at... 

Clausen AE, Bernkop-Schnurch A. Direct compressible poly-methacrylic acid-starch compositions for site-specific drug delivery. J Control Release 2001 75 93-102. 

The nasal cavity and the rectum are unique sites of drug delivery in that the drugs will be absorbed directly into the bloodstream. These routes have been explored for possible use. 

If one were to imagine the ideal drug-delivery system, two prerequisites would be required. First, it would be a single dose for the duration of treatment, whether it be for days or weeks, as with infection, or for the lifetime of the patient, as in hypertension or diabetes. Second, it should deliver the active entity directly to the site of action, thereby minimizing or eliminating side effects. This may necessitate delivery to specific receptors, or to localization to cells or to specific areas of the body. 

The buccal mucosa, which lines the inside of the cheek, has been investigated as an alternative route for drug delivery, especially for proteins and peptides. There are many advantages associated with the use of the buccal mucosa as a site for the delivery of drugs into the systemic circulation. Since blood flow from the buccal epithelium drains directly into the internal jugular... 

A special group of carrier-linked prodrugs are the site-specific chemical delivery systems [23], Macromolecular prodrugs are synthetic conjugates of drugs covalently bound (either directly or via a spacer) to proteins, polypeptides, polysaccharides, and other biodegradable polymers [24],... 

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