The use of gamma-emitting radionuclides for diagnostic imaging in
nuclear medicine has been established for many years. Sophisticated
gamma ray detecting camera systems and computer links enable the
clinical investigator to image different regions of the body and to
quantify organ function. Parallel developments have also occurred in the
field of radiopharmaceuticals, and today a wide range of products is
available that will exhibit specific uptake within target tissues
following parenteral administration. For example, radioiodide is taken
up by the thyroid and iodinated fatty acids can be used to image the
myocardium. Labelled antibodies have been used with success to target
certain tumours. The concept of targeting has also been considered by
pharmaceutical scientists who wish to deliver drugs rather than
radionuclides to specific sites in the body. The systems that have been
employed are often physically similar to those used as
radiopharmaceuticals (for example colloids, aerosols and liposomes).
Furthermore, pioneering work by Digenis and others in the United States
States and by Alpsten and co-workers (1976)in Sweden had demonstrated
the potential of gamma scintigraphy for investigating the fate of
tablets and capsules in the gastrointestinal tract of man in a non-
invasive way. In 1979, the Biopharmaceutics Research Group at Nottingham
together with academic pharmacists from Manchester held a one-day
syffiposium at Nottingham University to discuss how radio- nuclides
could be used in drug formulation studies to provide better approaches
for the delivery of drugs to their sitesof action.
