Ionic Hydrogel for Accelerated Dopamine Delivery via Retrodialysis.

Local drug delivery directly to the source of a given pathology using retrodialysis is a promising approach to treating otherwise untreatable diseases. As the primary material component in retrodialysis, the semipermeable membrane represents a critical point for innovation. This work presents a new ionic hydrogel based on polyethylene glycol and acrylate with dopamine counterions. The ionic hydrogel membrane is shown to be a promising material for controlled diffusive delivery of dopamine. The ionic nature of the membrane accelerates uptake of cationic species compared to a nonionic membrane of otherwise similar composition. It is demonstrated that the increased uptake of cations can be exploited to confer an accelerated transport of cationic species between reservoirs as is desired in retrodialysis applications. This effect is shown to enable nearly 10-fold increases in drug delivery rates from low concentration solutions. The processability of the membrane is found to allow for integration with microfabricated devices which will in turn accelerate adaptation into both existing and emerging device modalities. It is anticipated that a similar materials design approach may be broadly applied to a variety of cationic and anionic compounds for drug delivery applications ranging from neurological disorders to cancer

Moclobemide and imipramine in chronic depression (dysthymia): An international double-blind, placebo-controlled trial

An international, multicenter, placebo-controlled study was undertaken to determine the safety and antidepressant efficacy of moclobemide, a new reversible inhibitor of monoamine oxidase A, and imipramine in the treatment of dysthymia (DSM-III-R). A total of 315 patients were enrolled and randomly assigned to an 8-week treatment in one of three groups (moclobemide, imipramine and placebo). Patients were male or female outpatients aged between 18 and 65 years meeting DSM III-R criteria for dysthymia, primary type, with late or early onset. Of the patients in each group 85% completed the 8-week treatment period. The percentage of patients who no longer fulfilled DSM-III-R symptom criteria at treatment end-point was significantly higher in the moclobemide (60%) and imipramine (49%) treatment groups than in the placebo group (22%). Differences to placebo were also statistically significant both for moclobemide and for imipramine on the other efficacy variables (i.e. Hamilton Rating Scale

Reducing Passive Drug Diffusion from Electrophoretic Drug Delivery Devices through Co‐Ion Engineering

Funder: Cambridge Trust and Ministry of EducationFunder: University of Cambridge Borysiewicz Fellowship programFunder: Biotechnology and Biological Sciences Research Council David Phillips FellowshipFunder: European Union's Horizon 2020 research and innovation programmeFunder: Trinity Hall Research StudentshipAbstract: Implantable electrophoretic drug delivery devices have shown promise for applications ranging from treating pathologies such as epilepsy and cancer to regulating plant physiology. Upon applying a voltage, the devices electrophoretically transport charged drug molecules across an ion‐conducting membrane out to the local implanted area. This solvent‐flow‐free “dry” delivery enables controlled drug release with minimal pressure increase at the outlet. However, a major challenge these devices face is limiting drug leakage in their idle state. Here, a method of reducing passive drug leakage through the choice of the drug co‐ion is presented. By switching acetylcholine's associated co‐ion from chloride to carboxylate co‐ions as well as sulfopropyl acrylate‐based polyanions, steady‐state drug leakage rate is reduced up to sevenfold with minimal effect on the active drug delivery rate. Numerical simulations further illustrate the potential of this method and offer guidance for new material systems to suppress passive drug leakage in electrophoretic drug delivery devices