A new model of resorbable device degradation and drug release - part I: zero order model

BACKGROUND: Within the field of resorbable devices, recent years have seen an increased demand for better reliability from drug delivery systems and resorbable polymer degradation control, causing researchers to abandon trial-and-error approaches towards model-based methods. In this context, we developed a lumped-parameters zero-order model for the degradation of resorbable polymeric drug release systems. Such a model is thought to be applicable in the design of specific devices based on the expected degradation time and drug delivery rates, as it is based on a 'shrinking core' approach and takes into account the main physicochemical parameters involved in polymer degradation, in drug release and in mechanical strength prediction, all independently estimated. RESULTS: The model, based on conservation equations, leads to numerically solved ordinary differential equations, the predictions of which were verified through literature data. Data of different authors and various systems were satisfactorily matched by model predictions, thus confirming the reliability of parameter estimation procedures. CONCLUSION: The present model is among the very few that completely address all aspects involved in device degradation and drug delivery altogether, and thus represents a step ahead with respect to current available solutions, firmly enforcing itself into the ongoing debate on the modelling of degradation and release behaviour. (c) 2008 Society of Chemical Industry.