To better understand and "program" the drug release in human plasma, a kinetic characterization of the process is necessary for every drug ligand and macromolecular support. Due to few observed species and limited standard information, process modelling based on extended kinetic structures is difficult. Laboratory experiments that mimic the natural conditions and the bio-environment, together with statistical estimators allow identification of reduced (apparent) kinetic models. The scope of this paper is to present a more systematic approach to interpret the kinetic models and to link the identified apparent rate/equilibrium constants to kinetic characteristics of an extended "intrinsic" reaction path. The developed stoichiometric analysis and linear lumping rules are exemplified for a case study from literature, that considers a four-ligands ("drug" dansyl groups) release from a dendrimeric support structure in a reducing environment that mimic the human plasma. (C) 2004 Elsevier Ltd. All rights reserved.