In the majority of cases, new formulations/drug products are evaluated in a standard human PK study. However, invaluable insights on the performance of a drug product can often be gained by incorporating a gamma emitting radiolabel into the drug product and performing a pharmacoscintigraphic study.
Visualising the drug product as it transits through the gastrointestinal tract provides information about its location and state of disintegration, which can then be correlated with the PK of the molecule. Conclusions can be drawn aboutthe performance of the formulation including the ability of a formulation to target a specific location, the rate of erosion in comparison with in vitro dissolution data and the impact of absorption windows on bioavailability. Incorporating scintigraphic labelling into RapidFACTTM programmes has proven extremely valuable to many clients.
Scintigraphic assessments of drug products for locally acting compounds can be used as a method to determine product performance in the absence of PK data. Visual confirmation and quantification of the delivery of drug product to the target site is a recognised method to assess bioequivalence.