ABSTRACT
This chapter examines general approaches and utility of in vivo/in vitro correlations and associations. In vitro tests must be validated by an in vivo correlation/association to be a meaningful quality control tool and to be useful as a surrogate marker for in vivo performance. Science and regulatory issues relative to in vivo/in vitro correlations have been topics of several national and international conferences and publications. For immediate-release products, useful correlations may sometimes be developed for several dosage forms, i.e., a correlation or association is applicable irrespective of formulation differences. Two general relationships can be defined between in vitro dissolution and in vivo bioavailability as follows: in vivo/in vitro correlations; and in vivo/in vitro associations. The in vivo parameters essential for correlation and/or association with in vitro data are obtained from bioavailability and/or bioequivalence studies in humans. In vitro parameters for correlation and/or association with in vivo performance parameters are obtained from in vitro dissolution test procedures that yield dissolution profiles.
