Non-delaminating pulsatile release composites

Abstract By sequestering individual doses of chemical in stimuli-sensitive depot membranes and stacking them between stimulant barriers, automated pulsatile chemical release can be obtained from a simple polymer laminate. By using non-degrading hydrogel depots, this approach has been demonstrated releasing multiple chemicals in up to ten pulses, with each depot membrane delaminating and releasing its payload at a preprogrammed time. This paper reports the first experimental demonstration of a non-delaminating, non-degrading pulsatile release composite, for applications where delamination may be unsuitable. Non-delaminating systems not only require significantly larger development resources, they have an inherent periodicity limit which increases with the number of pulses desired. This limit is not analytically tractable, prompting the development of a computational model to predict the complete release profile. This model is validated against experimental delaminating systems, then adapted to non-delaminating systems to correlate the system׳s pulsatility with the physical parameters of the system, including diffusion coefficients, stimulant concentration, solute loading, scavenger loading and membrane thicknesses. These correlations facilitate rapid feasibility assessment of proposed non-delaminating pulsatile release applications prior to development of physical systems.