Assessment of in vivo drug dissolution by means of numerical deconvolution considering gastrointestinal availability

Abstract Numerical deconvolution has been applied for calculating the in vivo dissolution process. Due to intraindividual variations in drug absorption on different occasions of administration, a misleading picture of the actual amount dissolved in vivo can be obtained. A modified method for calculating the amount of drug dissolved in vivo is presented which considers both the reference formulation (weighting function) and the test formulation (response function) as equally available to the gastrointestinal tract, i.e. the place where the dissolution process actually occurs. The potential antipsychotic compound, remoxipride, administered as controlled release microcapsules, is used as a model system. It is demonstrated that if the deconvolution data are compensated for the amount of remoxipride absorbed from each formulation (test and reference), very good quantitative in vitro/in vivo dissolution correlations are obtained for each subject. The impact of considering both the conventional deconvolution curve and the modified one will be discussed.