Correlation of bioavailability in man with simulated absorption data for three doxantrazole preparations.

The in vitro and in vivo availability of doxantrazole, a potential antiallergic compound has been evaluated. A solution was significantly less bioavailable than either tablet or suspension formulations and it is suggested that this is associated with the large volume of the solution vehicle altering the hydrophilicity of the gastrointestinal fluids. In vitro availability was determined from absorption rate constants and absorption profiles obtained using the Sartorius absorption and solubility simulators. A statistically significant correlation was found between the percentage absorbed in vitro at 1 h and both total urinary recovery and area under plasma curve values in vivo. It is considered that in vitro determination of diffusion through artificial lipid membranes may be a useful predictive method of in vivo availability.