Publications by authors named "Yeon Hee Yun"

The modern day drug delivery technology is only 60years old. During this period numerous drug delivery systems have been developed. The first generation (1950-1980) has been very productive in developing many oral and transdermal controlled release formulations for clinical applications.

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Various pharmaceutical particles have been used in developing different drug delivery systems ranging from traditional tablets to state-of-the-art nanoparticle formulations. Nanoparticle formulations are unique in that the small size with huge surface area sometimes provides unique properties that larger particles and bulk materials do not have. Nanoparticle formulations have been used in improving the bioavailability of various drugs, in particular, poorly soluble drugs.

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Carrier geometry is a key parameter of drug delivery systems and has significant impact on the drug release rate and interaction with cells and tissues. Here we present a piezoelectric inkjet printing system as a simple and convenient approach for fabrication of drug-loaded polymer microparticles with well-defined and controlled shapes. The physical properties of paclitaxel (PTX)-loaded poly(lactic-co-glycolic acid) (PLGA) inks, such as volatility, viscosity and surface tension, were optimized for piezoelectric inkjet printing, and PTX-loaded PLGA microparticles were fabricated with various geometries, such as circles, grids, honeycombs, and rings.

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Piezoelectric inkjet printing of polymers and proteins holds great promise for fabrication of miniaturized bioelectronic devices, such as biochips and biosensors. In this study, a bienzymatic glucose biosensor prototype based on poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT-PSS), glucose oxidase (GOD), and horseradish peroxidase (HRP) was fabricated by a piezoelectric inkjet printer. An aqueous bioelectrical ink containing PEDOT-PSS, GOD, and HRP was prepared and printed on an indium-tin-oxide (ITO)-coated poly(ethylene terephthalate) (PET) film.

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In a continuing search for compounds with antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), a chloroform extract of roots of Aralia continentalis was found to contain continentalic acid (CA, C(20)H(30)O(2)), a diterpenic acid. This compound exhibited potent activity against standard methicillin-susceptible Staphylococcus aureus (MSSA) as well as clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). It was determined that continentalic acid had minimum inhibitory concentrations (MICs) of approximately 8-16 microg/mL against S.

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