(351c) Pulsed Release Through Layered Polymers

In recent years, pulsed release of drugs has been of interest to achieve improved pharmaceutical therapies. To date, most pulsed release systems have relied on user intervention or complex devices (timers, pumps) limiting the application in which they are feasible. We have developed a barrier-mediated pulsed release (BMPR) system in which individual doses of drug are loaded within stimuli-sensitive hydrogels (depots) which release solute only upon contact by a stimulant. These depots are protected by reactive barrier layers which scavenge the stimulant for a controllable period of time, tuning the delay time between pulses over a large range. We have demonstrated this tuned release from a delaminating BMPR system using citric acid as model stimulant to produce multiple pulses of model drug (methylene blue) over a different range of timescales. We are now adapting this approach to a non-delaminating system whose performance cannot be predicted analytically. We have therefore built a computational model to predict the release profiles of these systems. The model framework assumes on Fickian diffusion of mobile species, binary hydrogel states and transport limited reaction kinetics. This presentation will discuss both the experimental and computational BMPR systems, analyze their agreement, and introduce efforts to further generalize this delivery strategy by incorporation of glucose as the stimulant.