pH-responsive drug-delivery devices for implantable applications

A drug-delivery microdevice integrating pH-responsive nano-hydrogel composite membranes functioning as intelligent nano valves is described. The polymeric microdevices are monolithic without requiring peripheral control hardware or additional components for controlling drug-release rates. pH-responsive nanoparticles were synthesized and embedded into a composite membrane. The resulting pH-responsive composite membrane was integrated with PDMS micro reservoirs to form the proof-of-concept microdevices. In vitro release characterization of the microdevices was conducted in which the release rate of Vitamin B₁₂ (VB₁₂) as a model drug increased dramatically when the local pH value was decreased from 7.4 to 4. By adjusting nanoparticle percentages, drug reservoir shape and size, and drug loading concentrations, complex drug release profiles in response to local pH changes can be achieved, functioning as a platform technology for intelligent drug delivery.