• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.379-384
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• 2021

A microneedle is a tool that used for drug delivery and diagnosis. Unlike general injections, the microneedle is short in length, enabling effective drug delivery while minimizing pain and risk of infection. Conventionally, microneedles have been manufactured precisely at a nanometer level based on microelectro mechanical systems (MEMS) technology, requiring expensive equipments & maintenance and complicated processes. To address the issues, 3D printing research has been conducted to fabricate microneedles simply, economically, and rapidly. Since 3D printing facilitates to manufacture prototypes and apply feedbacks, it is advantageous for the development and commercialization of microneedle for pharmaceuticals and cosmetics. Therefore, this review will introduce stereolithography (SLA), two-photon polymerization (2PP), dynamic light processing (DLP), continuous liquid interface production (CLIP), and fused deposition modeling (FDM) 3D printing technologies and also highlight research trends for microneedle production using them. Furthermore, the limitation of the current microneedle technology and the direction to be solved in the future will be discussed.

• Bulletin of Food Technology
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• v.9 no.2
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• pp.111-127
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• 1996

Potassium Sorbate의 향균능력측정결과 효모(Saccharomyces cerevisiae)의 성장에 대하여 uncompetitive 기작으로 작용하였다. 열처리 실험의 결과 Potassium Sorbate는 가열온도에 대하여 Arrhenius, 또한 가열시간에 대하여 1차반응식관계로 향균능력을 잃었으며 따라서 보존제로 Potassium Sorbate를 식품에 첨가후 포장, 가열살균하는 일반 식품가공공정상에서 가열살균공정이 첨가 보존제의 잔류향균능력을 잃게 하는 것으로 나타났다. 플라스틱 film과 치즈안에서 Potassium Sorbate의 확산계수 및 확산에 의한 물질전달 현상을 수학적모델과 컴퓨터 simulation 그리고 실험에 의해 구하였다. 저밀도폴리에틸렌(LDPE)이 범용플라스틱중에서 가장 작은 확산계수를 가져 빠른 물질전달이 요구되는 film층 또는 약물저장층으로 적합한것으로 나타났다. 그외 고밀도 폴리에틸렌(HDPE)과 폴리프로필렌(PP), 폴리에스터(PET)는 느린 물질전달이 요구되는층 또는 복합다층 film에서 물질전달에 단방향성을 주는 고차단층으로 적합한것으로 나타났다. Potassium Sorbate분말과 LDPE resin분말을 섞은후 단일스크루 익스트루더로 항균성 포장 film을 제조한 결과 LDPE film의 tensile strength과 elongation, elastic modulus는 Potassium Sorbate를 3% 이상 포함할때까지 변화하지 않았다. 그러나 film의 투명도는 급격히 낮아졌다. 향균성LDPE film은 효모가 접종된 한천배지상에서 항균물질인 Potassium Sorbate를 배지위로 서서히 방출시켜 효모의 성장속도(growth rate)를 저하시키고 초기성장지체기(lag period)를 연장시킨다. 따라서 식품포장재로 적용시에 미생물의 오염을 막고 식품저장기간을 연장할것이라 여겨진다.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.556-561
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• 2021

Recently, iron oxide nanoparticles have been used as the subject of many studies on drug delivery system (DDS) due to their excellent magnetic properties and biocompatibility in response to external magnetic fields. In this study, hyaluronic acid-superparamagnetic microneedles (HA-SMNs) and carboxy methyl cellulose-superparamagnetic microneedles (CMC-SMNs) containing superparamagnetic iron oxide nanoparticles (SIONs) were prepared with HA and CMC as a matrix materials of MNs (microneedles). Various properties of SMNs were then investigated with scanning electron microscopy (SEM), superconducting quantum interference device-vibrating sample magnetometer (SQUD-VSM), frequency mixing magnetic detection (FMMD), and polymer/bio membrane. The SQUID-VSM measurements showed superparamagnetism of HA-SMNs and CMC-SMNs containing SIONs. The FMMD results demonstrated that the signal intensity changed significantly as the concentration of SIONs increased. In addition, SMNs exhibited the average skin permeability intensities on the bio membrane for HA-SMNs and CMC-SMNs were 92.5 and 98.5%, respectively. These results suggested that SMNs could be utilized as deliver materials for a TDDS and MR molecular imaging.

• The Journal of the Acoustical Society of Korea
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• v.41 no.5
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• pp.564-569
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• 2022

Blood-Brain Barrier (BBB) is the brain protecting system blocking the inflow of harmful substances into brain parenchyma from brain blood vessel. However, the BBB has a negative effect on the treatment of various brain diseases such as Alzheimer's dementia or brain tumors because it also prevents drug delivery into brain parenchyma. To overcome this problem, a brain drug delivery technique using Focused Ultrasound (FUS) which allows BBB to be temporarily opened by inducing the acoustic cavitation effect of microbubbles has been developed. Thus far, various studies using the FUS technique has been conducted to improve drug delivery efficiency, and therefore, this paper discusses recently developed drug delivery technologies using the FUS-induced BBB opening.

• Polymer(Korea)
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• v.29 no.3
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• pp.260-265
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• 2005

The initial burst of drug release is an important role in the controlled delivery of drug having hish toxicity and narrow therapeutic ranges. Nanosphere composed of monolayer could not achieve precisely controlled drug release because of the initial burst of drug on surface. In this study, double layered nanosphere was prepared for sustained drug delivery without initial burst. Double layered nanosphere composed of dextran and PLGA was fabricated by using conventional W/O/W double emulsion method. To control surface tension on the outer layer of nanospheres, PVA was used as a surfactant. Release behavior of dextran as model drug was observed as the $3{\times}1$mm wafers formed by compression mould in the deionized water for 7 days. Double layered nanosphere has sustained release behavior, in contast to single layered nanospheres. such as mechanical mixture and dextran nanospheres. Especially, nanosphere containing PVA $0.2\%$ has shown nearly the zero-order release profile. As a result of this study, double layered nanospheres has more sustained release profile of drug without the initial burst and the release behavior of dexoan on tile double layered nanospheres was controlled by the contents of PVA as a surfactant.

• Journal of Biomedical Engineering Research
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• v.38 no.1
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• pp.43-48
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• 2017

Chemotherapy, radiation therapy, and surgery are major methods to treat cancer. However, current cancer treatments report severe side effects and high recurrences. Recent studies about engineering nanoparticles as a drug carrier suggest possibilities in terms of specific targeting and spatiotemporal release of drugs. While many nanoparticles demonstrate lower toxicity and better targeting results than free drugs, they still need to improve their performance dramatically in terms of targeting accuracy, immune responses, and non-specific accumulation at organs. One possible way to overcome the challenges is to make precisely controlled nanoparticles with respect to size, shape, surface properties, and mechanical stiffness. Here, we demonstrate $500{\times}200nm$ discoidal polymeric nanoconstructs (DPNs) as a drug delivery carrier. DPNs were prepared by using a top-down fabrication method that we previously reported to control shape as well as size. Moreover, DPNs have multiple payloads, poly lactic-co-glycolic acid (PLGA), polyethylene glycol (PEG), lipid-Rhodamine B dye (RhB) and Salinomycin. In this study, we demonstrated a potential of DPNs as a drug carrier to treat cancer.

• Journal of the Korean Chemical Society
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• v.60 no.3
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• pp.187-193
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• 2016

In this study, preparation of positively and negatively charged carbon nanotube (CNT)-collagen (CG) hydrogels with pH sensitive characteristic was reported. The positive and negative characteristics of the prepared hydrogels were created by introduction of positively functionalized CNT-NH₂ and negatively functionalized CNT-COOH, respectively, into the collagen hydrogel. The surface charge of CNTs (CNT-NH₂ and CNT-COOH), CG and CNTs/CG hydrogels was measured by Zetasizer. The swelling ratios of CNT-NH₂/CG and CNT-COOH/CG hydrogels in aqueous solution were checked by measuring of weight changes of the hydrogels in the range of pH 2~10. In detail, the positively charged CNT-NH₂/CG hydrogel swelled up to 5% at pH 4 in comparison to the weight at pH 7, while the negatively charged CNT-COOH/CG hydrogel swelled up to 10% at pH 10. The prepared CNT-NH₂/CG and CNT-COOH/CG hydrogels will be very useful as pH sensitive oral drug-delivering systems for gastrointestine (pH ~2) and small intestine (pH ~9), respectively.

• Journal of IKEEE
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• v.28 no.1
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• pp.97-103
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• 2024

Some drugs can offer far better medical effectiveness as it is injected through the intradermal layer of the skin, known as a needle-free injection. However, conventional needle-free devices might deliver a relatively large amount of drug in a just single spot of skin, splitting open the tissue layer structure, which might cause bruising and bleeding. By injecting the small volume with a fast repetition rate in a large surface area of skin, the patient may get much fewer injuries and pain. To achieve that specification, the driving force must be instantaneous and short-pulsed. Such a form of an injection device has been developed but the efficacy of those devices has been rarely examined. Therefore, this study developed the laser-induced microjet device that ejects microjet whose speed is ~310 m/s, during the 400~800 ㎲ of pulse time. The device can eject ~1 µL of the drug at the rate at which each shot repeated 10 shots per second. Using this specification, we evaluated the efficacy of drug injection onto mouse models. After injecting the insulin solution into the mouse model, the blood insulin level is detected, resulting in 20 % of blood insulin level with the ordinary needle syringe injection method.

• Polymer(Korea)
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• v.32 no.4
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• pp.328-333
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• 2008

The osmotic delivery systems are based on osmosis. The transverse diffusion of water through a porous membrane from a medium with a low osmotic pressure to a medium with a high osmotic pressure. Nifedipine tablet dosage forms of Procardia $XL^{(R)}$(Pfizer) and $Adalat^{(R)}$(Bayer) are commercialized systems of this type that push-pull osmotic tablet operates successfully in delivering water-insoluble drugs. We prepared osmotic pellet system by fluidized bed coating method, and model-drug used nifedipine. The osmotic pellet system was composed of the core material. the swelling and osmotic pressure layer, the drug coating layer, and the porous membrane. This work is performed to investigate the effect of different factors, such as composition and thickness of membrane. The osmotic pellet has been successfully prepared by fluidized bed coating technology. The drug release behavior depended on the increase of CA ratio and thickness in porous membrane. The morphology of the osmotic pellet before and after the dissolution test were observed by SEM. In conclusion, we found that the drug release of osmotic pellet depended on the composition and coating thickness of porous membrane.

• Polymer(Korea)
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• v.29 no.3
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• pp.288-293
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• 2005

Osmotic granule system which is one of the drug delivery systems has been developed to improve manufacturing process and other problems of tablet osmotic systems. It consists of water swellable seed layer, nifedipine drug layer, and drug release controlled membrane layer and manufactured by fluidized bed coater. The granule size and mombrane thickness can be controlled by various amounts of seed and coating solution, respectively. It could be observed that the morphology of osmotic granule was different at each coating step as well as type of coating solution. The bigger the size of granule, the slower the release rate was observed due to decreasing the total specific surface wed of granule. Also, it was observed that the increase of membrane thickness was caused to retard the dissolution of nifedipine due to decreasing the water absorption rate. The drug solubility for dissolution media is greatly affected to nifedipine release. From these results, we assured that osmotic granule can be fabricated by fluidized bed coating methods, and the appropriate release profile could be controlled by the controlling of bead size, membrane thickness and dissolution media.