Nuclear medicine techniques in the evaluation of pharmaceutical formulations

Nuclear medicine imaging techniques have great potential in the study of the behaviour of drug formulations and drug delivery systems in human subjects. No other technique can locate so precisely the site of disintegration of a tablet in the G1 tract, the depth of penetration of a nebulised solution into the lung, or the residence time of a drug on the cornea. Using the gamma camera to image the in vivo distribution of pharmaceutical formulations radiolabelled with a suitable gamma emitting radionuclide, images may be used to quantify the biodistribution, release and kinetics of drug formulations and delivery from novel carrier systems and devices. Radionuclide tracer techniques allow correlation between the observed pharmacological effects and the precise site of delivery. The strength of the technique lies in the quantitative nature of radionuclide images. Such studies not only provide data on the nature and characteristics of a product, such as reliability and reproducibility but, may also be used in submission to Regulatory Authorities in product registration dossiers.