Controlled release of ranitidine from conductive polypyrrole films

Incorporation and controlled release of active substances from the conductive polypyrrole films by electric stimulation were investigated. Change of the redox state of the conductive polymer was induced by this stimulation, which allowed the incorporation and release of the drug at different rates. Polymerization of pyrrol on a stainless steel substrate was performed by cycling the potential 40 times in predetermined potential window, after which uniform polymeric film was formed and used as a medium for incorporation and release of the active substance. Stability of obtained films, as well as the electrochemical behaviour of ranitidine hydrochloride was investigated by cycling the potential of the film electrode in 0.9 % NaCl in the same potential window used for the polymerization. Uptake and release of the active substance was performed at constant potential and monitored by chronoamperometry. Although incorporation of the ranitidine hydrochloride was not obvious from the measured infrared spectra, incorporation and release was confirmed and quantified by monitoring the concentration of the active substance in the electrolyte. It was determined that maximum reversible uptake was 351 μg cm-2. However, successive potential stimuli did not result in the equal released quantity, as expected for the ideal controlled-release system based on conducting polymers

Controlled release of ranitidine from conductive polypyrrole films

Incorporation and controlled release of active substances from the conductive polypyrrole films by electric stimulation were investigated. Change of the redox state of the conductive polymer was induced by this stimulation, which allowed the incorporation and release of the drug at different rates. Polymerization of pyrrol on a stainless steel substrate was performed by cycling the potential 40 times in predetermined potential window, after which uniform polymeric film was formed and used as a medium for incorporation and release of the active substance. Stability of obtained films, as well as the electrochemical behaviour of ranitidine hydrochloride was investigated by cycling the potential of the film electrode in 0.9 % NaCl in the same potential window used for the polymerization. Uptake and release of the active substance was performed at constant potential and monitored by chronoamperometry. Although incorporation of the ranitidine hydrochloride was not obvious from the measured infrared spectra, incorporation and release was confirmed and quantified by monitoring the concentration of the active substance in the electrolyte. It was determined that maximum reversible uptake was 351 μg cm-2. However, successive potential stimuli did not result in the equal released quantity, as expected for the ideal controlled-release system based on conducting polymers

UNDERGRADUATE APPLICATION BASED RESEARCH: DESIGN AND TESTING OF WIRELESS PHONE CHARGER

Currently, there exists an abundance of handheld electronic devices, especially smart phones that require frequent charging. Traditionally, these devices were charged by using wired power adapters (chargers). However, the use of wires poses limits in terms of user convenience and distance from electrical outlets. While wireless chargers exist, commercial widespread use of the technology for consumer electronics is relatively recent. Also, the application of the underlying science and engineering principles of power transfer wirelessly are not commonly explored in Electrical Engineering Technology (EET) programs. In this paper, the authors report their findings and present the results of application- based research on the prototyping and testing of a wireless charger. This research was conducted as an independent study course by one student, who was supervised by an Electrical Engineering Technology professor. The design procedure is explained, tests results are presented, lessons learned are discussed, and ways in which the project could be incorporated into the lab component of an Electrical Engineering Technology course are suggested. Lastly, the authors suggest ways in which their design and approach could be improved

Fraction of grains development measured by electrolytic grain size analyzer

Quantum sensitivity is an important emulsion property for photographic image formation and is usually calculated from a fraction of grains developable vs. log exposure (F-log E) curve. In this thesis, a new method, the electrolytic grain-size analyzer (EGSA) technique has been developed that will allow one to obtain F-log E curves for each grain size class in polydisperse emulsions. The correctness of the F-log E curve obtained by this new method has been examined by comparing the F-log E curve with that calculated from the normalized D-log E curve in the case of monodisperse emulsions. The problems in EGSA measurement, such as noise and emulsion solubility, which affect the accuracy of F-log E curves obtained by such a method, have been solved and are discussed in detail. The technique has been applied to the case of an emulsion with a bimodal grain size distribution

In-situ absorption and fluorescence studies of electrogenerated species

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Electrochemical, spectrophotometric, electroanalytical and electrochemical quartz crystal microbalance studies of some redox-active films

Redox films are a broad class of electrochemically active films with many potential uses. In the present work, Prussian Blue and carbon coated electrodes have been investigated as possible electrochemical sensors for ascorbic acid and pH, respectively. The potential of Prussian Blue as an optical sensor has also been investigated. In the case of Prussian Blue, it has been discovered that up to 100 monolayers can be systematically deposited on gold electrodes by a new technique that we have called "directed assembly". This provides control of layer thickness with nanometer precision. In the case of carbon coated electrodes, we have developed a mechanical coating technique for quartz crystals, which allows them to be used in electrochemical cells, simultaneously as working electrodes and as mass sensors in a quartz crystal microbalance. This opens up the possibility of developing a variety of new sensor technologies, including pH-sensitive microelectrodes

Implications of External Memory for Investigations of Mind

External memory–records of experiences that are maintained in repositories that are external to their users–provides context for many everyday cognitive acts. Some initial research has shown that such context influences learning, remembering, and judgements of knowing. The scope of both basic and applied memory research should be broadened in ways that address issues about the interaction of external memory and mind

Analysis and design of resonant inductively coupled circuits : application to benefit denial solutions for the retail industry

Thesis: M. Eng. in Manufacturing, Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 81-82).ProTeqt develops benefit denial solutions that are electromagnetically deactivated. A magnetic field from the deactivation tablet inductively heats an enabler that provides the proper force to disengage the locking mechanism. Its latest design was not functional at one inch above the deactivation tablet, because of significant efficiency losses in the electromagnetic energy transfer. This is problematic when the product's package is thick. In order to improve the maximal functional distance, an LC circuit is inserted inside the locking device. This thesis describes the optimization and integration of the circuit, used as a weakly coupled electromagnetic resonator in wireless energy transfer. The most efficient resonator design is proposed, under the inherent constraints of this application. It is then tested in real situation in order to evaluate the failure rate of the complete device. Some modifications of the enabler are proposed and discussed to maximize the reliability. Finally, a simulation is conducted to test the sensitivity of the results to the circuit manufacturing variability. Under several clearly stated assumptions, it appears that the manufacturing variability of the hand-made enabler is the most significant, although it does not threaten the reliability of the current locking mechanism.by Amaury Rony.M. Eng. in Manufacturin

Metformin and cimetidine: Physiologically based pharmacokinetic modelling to investigate transporter mediated drug–drug interactions

Metformin is used as a probe for OCT2 mediated transport when investigating possible DDIs with new chemical entities. The aim of the current study was to investigate the ability of physiologically-based pharmacokinetic (PBPK) models to simulate the effects of OCT and MATE inhibition by cimetidine on metformin kinetics. PBPK models were developed, incorporating mechanistic kidney and liver sub-models for metformin (OCT and MATE substrate) and a mechanistic kidney sub-model for cimetidine. The models were used to simulate inhibition of the MATE1, MATE2-K, OCT1 and OCT2 mediated transport of metformin by cimetidine. Assuming competitive inhibition and using cimetidine Ki values determined in vitro, the predicted metformin AUC ratio was 1.0 compared to an observed value of 1.46. The observed AUC ratio could only be recovered with this model when the cimetidine Ki for OCT2 was decreased 1000-fold or the Ki's for both OCT1 and OCT2 were decreased 500- fold. An alternative description of metformin renal transport by OCT1 and OCT2, incorporating electrochemical modulation of the rate of metformin uptake together with 8–18-fold decreases in cimetidine Ki's for OCTs and MATEs, allowed recovery of the extent of the observed effect of cimetidine on metformin AUC. While the final PBPK model has limitations, it demonstrates the benefit of allowing for the complexities of passive permeability combined with active cellular uptake modulated by an electrochemical gradient and active efflu

Trinity Tablet, May 2, 1903

https://digitalrepository.trincoll.edu/tablets/1515/thumbnail.jp