The Effect of Active Pharmaceutical Ingredients on Aerosol Electrostatic Charges from Pressurized Metered Dose Inhalers

The final publication is available at Springer via: http://dx.doi.org/10.1007/s11095-015-1674-6.Purpose. This study investigated the effect of different active pharmaceutical ingredients (API) on aerosol electrostatic charges and aerosol performances for pressurized metered dose inhalers (pMDIs), using both insulating and conducting actuators. Methods. Five solution-based pMDIs containing different API ingredients including: beclomethasone dipropionate (BDP), budesonide (BUD), flunisolide (FS), salbutamol base (SB) and ipratropium bromide (IPBr) were prepared using pressure filling technique. Actuator blocks made from nylon, polytetrafluoroethylene (PTFE) and aluminium were manufactured with 0.3 mm nominal orifice diameter and cone nozzle shape. Aerosol electrostatics for each pMDI formulation and actuator were evaluated using the electrical low-pressure impactor (ELPI) and drug depositions were analysed using high performance liquid chromatography (HPLC). Results. All three actuator materials showed the same net charge trend across the five active drug ingredients, with BDP, BUD and FS showing positive net charges for both nylon and PTFE actuators, respectively. While SB and IPBr had significantly negative net charges across the three different actuators, which correlates to the ionic functional groups present on the drug molecule structures. Conclusions. The API present in a pMDI has a dominant effect on the electrostatic properties of the formulation, overcoming the charge effect arising from the actuator materials. Results have shown that the electrostatic charges for a solution-based pMDI could be related to the interactions of the chemical ingredients and change in the work function for the overall formulation

Polarized ATR-FTIR spectroscopy of the membrane-embedded domains of the particulate methane monooxygenase.

[[sponsorship]]化學研究所[[note]]已出版;[SCI];有審查制度;具代表性[[note]]http://gateway.isiknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Drexel&SrcApp=hagerty_opac&KeyRecord=0006-2960&DestApp=JCR&RQ=IF_CAT_BOXPLO

A Novel PET-Based Piezoresistive MEMS Sensor Platform for Agricultural Applications

A simple and cost effective process is demonstrated for fabricating polyethylene terephthalate (PET) cantilever-based sensor platform with piezoresistive transduction. A one step method is developed to coat graphene nanoplatelet piezoresistive layer on to the PET structural layer. The proposed platform can be used for a variety of sensing applications. The novelty of this process is that it does not require any expensive lithography tools or a specialized clean room facility. We report here the fabrication, characterization, and application of this sensor for the detection of soil macronutrients. Ours is the first report demonstrating the use of PET-based microelectromechanical system for agricultural sensing application

Polymeric Piezoresistive Microcantilevers With Reduced Electrical Variability

The observed electrical variability has limited the usage of the carbon black (CB)-SU8 (an epoxy polymer of di-glycidyl ether of bisphenol A) nanocomposite as a piezoresistive element in the microelectromechanical systems-based sensor applications. We report here a simple modification to the CB-SU8 nanocomposite preparation, which improves the dispersion of the CB particles in the SU8 polymer matrix creating a CB-SU8 photopatternable nanocomposite with a stable conductive network. The modified CB-SU8 nanocomposite was used as the piezoresistive element to fabricate microcantilever devices for strain sensing applications. Improved stability of these microcantilever devices is reflected from their electrical characterization. The electromechanical characterization of these microcantilevers demonstrated their piezoresistive behavior

Zinc oxide nanorods functionalized paper for protein preconcentration in biodiagnostics

Distinguishing a specific biomarker from a biofluid sample containing a large variety of proteins often requires the selective preconcentration of that particular biomarker to a detectable level for analysis. Low-cost, paper-based device is an emerging opportunity in diagnostics. In the present study, we report a novel Zinc oxide nanorods functionalized paper platform for the preconcentration of Myoglobin, a cardiac biomarker. Zinc oxide nanorods were grown on a Whatman filter paper no. 1 via the standard hydrothermal route. The growth of Zinc oxide nanorods on paper was confirmed by a combination of techniques consisting of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS,) scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) analysis. The Zinc oxide nanorods modified Whatman filter paper (ZnO-NRs/WFP) was further tested for use as a protein preconcentrator. Paper-based ELISA was performed for determination of pre-concentration of cardiac marker protein Myoglobin using the new ZnO-NRs/WFP platform. The ZnO-NRs/WFP could efficiently capture the biomarker even from a very dilute solution (Myoglobin < 50 nM). Our ELISA results show a threefold enhancement in protein capture with ZnO-NRs/WFP compared to unmodified Whatman filter paper, allowing accurate protein analysis and showing the diagnostic concept