ract The ability to externally control release from implants offers a safer and more efficient way of delivering drugs to the body as compared to traditional drug depots that rely upon diffusion and do not allow for a change in dosage after implantation. Previous studies employed magnetic nanoparticle (NP)-loaded shape memory polymer (SMP) films to determine if magnetic actuation could be used to release a model drug (rhodamine B) from strained and unstrained samples and to establish structure/property relationships regarding drug release from SMPs. This previous study was limited by short release time characterization periods (7 hours) and does not provide long-term release information from these scaffolds. To address this limitation, the current study analyzed how magnetic actuation affects release of rhodamine B from both strained and unstrained SMP films with varied chemistries (crosslinked and uncrosslinked) in accelerated hydrolytic (0.1M NaOH), accelerated oxidative (20% H2O2), and ‘real time’ (PBS) media over 26 days. As a proof-of-concept for further control over release, rhodamine B was first loaded into microparticles (µP), which were subsequently incorporated into SMP scaffolds to evaluate release over time. General trends show that magnetic actuation in samples containing NPs increased release relative to those without. Linear (uncrosslinked) samples release significantly more rhodamine B than crosslinked samples. In these long-term studies, straining samples did not have an effect on release rates compared with non-strained samples. ‘Real time’ media allowed for the highest measured release. Accelerated oxidative media resulted in the lowest measured release, which is attributed to H2O2 oxidation of the rhodamine B. Lastly, incorporation of rhodamine B into microparticles prior to loading into films completely eliminated release of rhodamine B at the given mass used. This work acts as a proof-of-concept for controlling sustained drug delivery by varying SMP chemistry, straining, magnetic NP incorporation, and drug-loaded microparticles
