• 한국임상수의학회지
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• 제19권2호
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• pp.228-235
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• 2002

유방염은 젖소에 있어서 유량의 감소, 유질 저하로 인한 우유 폐기문제, 젖소의 도태, 치료비 및 노동력의 부담등을 초래하는 가장 경제적 손실이 큰 질환이다. 현재까지 비유기 최종 착유 후에 항생제를 주입하는 건유기 치료법이 유방염 관리에 가장 효과적이며 폭넓게 쓰이고 있는 방법으로 알려져 있다. 하지만, 건유기 치료는 건유기 주입 항생제 제품들이 건유기 초기에만 지속적인 활성을 지니기 때문에 건유기 말기와 분만 전기에 있어서의 신규 감염은 방어할 수 없다. 따라서 본 연구는 건유기 유방염 관리를 위해 PLGA를 이용한 서방형 생분해 cephalexin microsphere를 제조하여 이의 임상적 효능을 평가하고자 하였다. PLGA는 무독성의 조직 반응을 일으키지 않는 특성으로 인해 약물 방출 조절 체계의 일환으로 인정을 받아왔다. 본 연구에서 cephalexin microsphere는 표면에 특징적인 구멍을 가지고 있는 구형 모양으로 확인이 되었으며 약물 방출 시험에서 초기 과다 방출 이후로 21일간 약물의 방출이 점차 감소한 뒤 3주와 4주 사이에 2차 방출을 보이는 맥동성 방출 양상이 관찰되었다. 현장적용 시험에서는 cephalexin microsphere를 주입한 실험군에서 대조군에 비해 분만 후 신규 감염율 및 치료율, 평균 체세포 수의 변화의 측면에서 볼 때 유의성 있는 차이가 있음을 확인하였다. 따라서 생분해 microsphere를 이용한 건유기 치료법은 건유기 동안 신규 감염을 예방하고 기감염을 감소시킴으로써 종전의 건유기 치료를 좀 더 효과적으로 증진시킬 수 있을 것으로 사료된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.360.1-360.1
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• 2016

Hydroxyapatite (Ca10(PO4)6(OH)2, HAP) particles have attracted a great deal of attention in biomedical fields due to their good biocompatibility, bioactivity and fairly broad applications as drug delivery, dental implant, bone cement, and etc. Thus, many researchers have made an effort to add new functionalities such as luminescence, drug delivery, and bone regeneration properties up to HAP powders by controlling their nanostructure as well as composition. In this research, the mesoporous strontium substituted HAP (Sr-HAP) microspheres were synthesized using a hydrothermal method. In this synthesis, aspartic acid monomers were utilized to form microsphere by controlling surface energy of HAP particles and Sr ions were substituted into Ca ion sites, which induced luminescence property in HAP powders. Moreover, the change in the amount of Sr substitution was found to influence the particle size, morphology, and concurrently surface area, which led to changing drug loading as well as drug release property. The amount of Sr influences the morphology, luminescent properties, particle size, surface area cell viability and drug loading property, which are investigated by SEM, TEM, XRD, FTIR, BET, XPS and in vitro test such as MTT assay and drug release test. In particular, the multifunctional Sr-HAP with molar ratios of 0.25 (Sr/(Ca+Sr)) possessed the strongest luminescent property as well as the superior drug loading and sustained release properties that were correspondent with large surface area and pore size. Our study indicates that the fabricated multifunctional Sr-HAP microspheres are quite useful for bone regeneration and drug delivery.

• 공업화학
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• 제29권2호
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• pp.147-154
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• 2018

현재 항암제의 낮은 치료 효율과 부작용을 해결하기 위해 고분자 기반의 약물전달체의 연구가 활발하게 진행되고 있다. 기존의 고분자기반의 약물 전달체는 우수한 결과를 보이는 등 상당한 진전이 있었음에도 불구하고, 대부분 혈중에서 안정성이 감소하여 표적 부위에 도달하기 전에 약물이 방출될 뿐만 아니라 오랜 시간 동안에 약물을 방출함으로써 부작용 및 낮은 치료 효율을 초래한다는 문제점을 가지고 있다. 본 총론에서는 이러한 비효율적인 약물 방출의 문제점을 개선하기 위한 방법으로 독성이 없고 생체 적합한 천연 고분자 키토산에 자극 응답성 물질을 도입하여 혈중에서 안정성을 높이고 표적 부위에서 약물을 과다 방출하여 치료 효율을 극대화할 수 있는 방법을 제시하고자 한다.

• Macromolecular Research
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• 제14권5호
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• pp.530-538
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• 2006

There are three important components in tissue engineering: the cells, signaling factors (cytokines and growth factors), and scaffolds. To obtain finely engineered tissue, all three components should perform their individual functions and be fully integrated with each other. For the past few years, we have studied the characteristics of photodimerizable HA (CHA)/alginate (CA) composite materials. CHA/CA complex hydrogels, which were irradiated under UV light and, then treated with calcium ions, were found to have good biocompatibility, mechanical properties and water resistance for implantable tissue scaffolds. In this study, we introduced a cell growth factor (basic fibroblast growth factor; bFGF) into the CHA/CA scaffolds and studied its release behavior. We also introduced tetracycline hydrochloride and flurbiprofen into the same scaffolds as model activation factors and evaluated their release behaviors from the scaffolds. The drug release rate from the materials was influenced by various parameters, such as the degree of crosslinking, the cross linker type, the physico-chemical properties of the drug, and the amount of the drug in the polymer. The results indicated that the negatively charged CHA/CA composite materials showed sustained release behavior and that HA has a particularly strong negative charge, making it attractive toward tetracycline hydrochloride and bFGF, but repulsive toward flurbiprofen.

• Journal of Veterinary Science
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• 제25권2호
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• pp.30.1-30.16
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• 2024

Background: Biofilms, such as those from Staphylococcus epidermidis, are generally insensitive to traditional antimicrobial agents, making it difficult to inhibit their formation. Although quercetin has excellent antibiofilm effects, its clinical applications are limited by the lack of sustained and targeted release at the site of S. epidermidis infection. Objectives: Polyethylene glycol-quercetin nanoparticles (PQ-NPs)-loaded gelatin-N,O-carboxymethyl chitosan (N,O-CMCS) composite nanogels were prepared and assessed for the on-demand release potential for reducing S. epidermidis biofilm formation. Methods: The formation mechanism, physicochemical characterization, and antibiofilm activity of PQ-nanogels against S. epidermidis were studied. Results: Physicochemical characterization confirmed that PQ-nanogels had been prepared by the electrostatic interactions between gelatin and N,O-CMCS with sodium tripolyphosphate. The PQ-nanogels exhibited obvious pH and gelatinase-responsive to achieve on-demand release in the micro-environment (pH 5.5 and gelatinase) of S. epidermidis. In addition, PQ-nanogels had excellent antibiofilm activity, and the potential antibiofilm mechanism may enhance its antibiofilm activity by reducing its relative biofilm formation, surface hydrophobicity, exopolysaccharides production, and eDNA production. Conclusions: This study will guide the development of the dual responsiveness (pH and gelatinase) of nanogels to achieve on-demand release for reducing S. epidermidis biofilm formation.

• Journal of Pharmaceutical Investigation
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• 제40권spc호
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• pp.33-43
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• 2010

Hyaluronic acid (HA) is a biodegradable, biocompatible, non-toxic, non-immunogenic and non-inflammatory linear polysaccharide, which has been used for various medical applications including arthritis treatment, wound healing, ocular surgery, and tissue augmentation. Because of its mucoadhesive property and safety, HA has received much attention as a tool for drug delivery system development. It has been used as a drug delivery carrier in both nonparenteral and parenteral routes. The nonparenteral application includes the ocular and nasal delivery systems. On the other hand, its use in parenteral systems has been considered important as in the case of sustained release formulation of protein drugs through subcutaneous injection. Particles and hydrogels by various methods using HA and HA derivatives as well as by conjugation with other polymer have been the focus of many studies. Furthermore, the affinity of HA to the CD44 receptor which is overexpressed in various tumor cells makes HA an important means of cancer targeted drug delivery. Current trends and development of HA as a tool for drug delivery will be outlined in this review.

• Biomolecules & Therapeutics
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• 제12권2호
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• pp.85-91
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• 2004

In all attempt to elucidate the role of apoptosis in drug resistance, cisplatin-resistant human chronic myelogenous leukemia (CML) K562 cells (K562/CDDP) were established and compared with drug sensitive parent cells (K562) in the induction of apoptosis. K562/CDDP cells were 5-fold more resistant to cisplatin compared to K562 cells. In addition, K562/CDDP cells were significantly more resistant to apoptois as judged by DNA fragmentation and DAPI staining. K562/CDDP cells exhibited decreased proleolytic activity of caspase-3 and this was further demonstrated by decreased cleavage of its substrate poly (ADP-ribose) polymerase (PARR- Western blot analysis showed that K562/CDDP cells had longer sustained levels of BCL-$X_L$ whereas no difference was noted in the level of Bcl-2. the translocation of Bax to mitochondria was significantly delayed in K562/CDDP cells. These results suggest that the reduced translocation of Bax and the sustained expression of BCL-$X_L$ may cause resistance to apoptosis through prevention of mitochondria release of cytochrome c, which subsequently induces reduction of caspase-3 activity and that this response is partly responsible for the acquired resistance to cisplatin ill K562 cells.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.469-477
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• 2018

We describe surgical sutures enabled with the local, sustained delivery of a TGF-${\beta}$ inhibitory drug, tranilast. To fabricate drug-delivery sutures, we separately prepared a tranilast-loaded strand using poly (lactic-co-glycolic acid), which was then physically braided with a surgical suture already in clinical use. By this method, the drug-delivery sutures maintained the mechanical strength and allowed the modulation of drug release profiles by simply altering the tranilast-loaded strand. The drug-delivery sutures herein released tranilast for up to 14 days. When applied to animal models, scarring was indeed reduced with diminished TGF-${\beta}$ expression and fibroblast numbers during the entire 21 day testing period.

• Korean Journal of Radiology
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• 제20권1호
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• pp.34-49
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• 2019

Conventional transcatheter arterial chemoembolization (c-TACE) is a widely used first-line palliative treatment for patients with unresectable hepatocellular carcinoma (HCC). Despite the effectiveness of c-TACE, to date, technique and procedure scheduling has not yet been standardized. Drug-eluting microspheres (DEMs) were therefore introduced to ensure more sustained and tumor-selective drug delivery for permanent embolization. These DEMs can load various drugs and release them in a sustained manner over a prolonged period. This approach ensures the delivery of high concentrations of chemotherapeutic agents to tumors, without increasing systemic concentrations, and promote tumor ischemia and necrosis. This review summarizes the recent advances in the use of DEM-TACE to treat HCC.

• 한국임상수의학회지
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• 제22권3호
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• pp.175-180
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• 2005

본 연구는 개에서 키토산 비드를 이용한 cefadroxil 방출에 영향을 주는 인자, 약물을 함유한 최적의 키토산 비드의 제조, 그리고 키토산 비드로부터 약물의 방출을 평가하는 것이다. 키토산 비드는 tripolyphosphate (TPP)와 이온결합으로 생성되며 비드의 크기는 1 mm 미만이었다. 비드로부터 cefadroxil 방출은 여러 인자에 영항을 받는다. TPP의 pH가 감소할수록 cefadroxil의 비드내 함유량은 증가하지만, 비드로부터 방출량은 감소한다. Cefadroxil의 방출속도은 TPP 농도가 증가할수록 감소한다. 결합시간이 길어지면, 방출량이 감소한다. Cefadroxil을 함유한 키토산 비드를 50 mg/kg 용량으로 건강한 개 4두의 피하에 이식한 결과, cefadroxil의 혈청내 농도는 1 ${\mu}g/ml$ 이상으로 7일간 유지되었다. 따라서 cefadroxil을 함유한 키토산 비드는 개의 농피증 치료에 유용한 것으로 사료되며 약물방출을 통제할 수 있는 약물수송체가 이용될 수 있다고 사료된다.