頭部戰傷에 關한 硏究

윤복영 延世大學校 大學院 1961 국내박사

Sb-SnO2 전극을 이용한 난분해성 물질의 전기분해와 수소발생에 관한 연구

윤복영 계명대학교 대학원 2008 국내석사

This study is to recognize the characteristics of non-biodegradable matters and to investigate the evaluation of H₂ considered next generation fuel by electrolysis. After making the electrode Ti/Sb-SnO₂ by thermal decomposition, the kind of electrolyte, the strength of current and the electrochemical degradation were measured according to pH. UV-Vis photospectrometer and HPLC were used to investigate the existence of intermediate in degradation measurement, and to know the organic fully-oxidation, the CO₂ which was the last product of organic was measured. In case of using the NaCl electrolyte, the organic was removed better than Na₂SO₄, and the evaluation of H₂ and intermediate also were much evaluated than Na₂SO₄ because of the reactivity and conductivity of Cl-. In case of Na₂SO₄ electrolyte, there was hardly evaluation of intermediate, the degradation was removed orderly following the time. The DaeGu-dying waste water degradation experiment which was conducted to know real application showed that NaCl electrolyte completely removed chromaticity but Na₂SO₄ had a little chromaticity. The limited current of Ti/Sb-SnO₂ is 5 mA/cm², and in case of 10 mA/cm², there happened the occurrence of crack on the surface of electrode because of rising voltage in electrolysis. 본 연구는 전기화학적 방법에 의한 난분해성 물질의 분해 특성을 파악하며 동시에 전기분해시 발생하는 차세대 연료인 수소생성을 조사하였다. 열분해법으로 Ti/Sb-SnO₂전극을 제조하여 전해질의 종류, 전류의 세기, pH에 따라 전기적인 분해를 측정하였다. 분해도 측정에는 UV-Vis photospectrometer와 HPLC로 중간생성물의 유무를 조사하였고, 난분해성 유기물의 최종산화물인 이산화탄소의 발생을 측정하여 유기물의 완전산화 여부를 조사하였다. NaCl 전해질을 사용한 경우에는 Na₂SO₄에 비해 비교적 잘 제거되나 Cl-의 반응성과 비전전도의 영향으로 중간생성물과 수소의 발생이 Na₂SO₄를 사용했을 때 보다 많이 생성되었다. Na₂SO₄ 전해질을 사용한 경우에는 중간생성물의 생성이 거의 없고 분해 물질이 시간에 따라 순차적으로 제거되었다. pH 변화에 따른 영향은 받지 않았으며, 실폐수 적용을 위해 대구염색공단의 방류수를 분해하는 실험에서 처리한계시간 30분으로 하여 NaCl의 경우 색도가 완전 제거되고 Na₂SO₄의 경우에는 약간의 색이 남아 있었다. Ti/Sb-SnO₂전극의 한계전류 밀도는 5 mA/㎠이며, 전류밀도 10 mA/㎠에서는 전기분해시 전압상승으로 전극표면에 균열이 생김을 알 수 있었다.

SMEDDS를 이용한 난용성 약물의 흡수율 개선에 관한 연구

윤복영 전북대학교 대학원 2003 국내석사

SMEDDS를 이용한 난용성 약물의 흡수율 개선에 관한 연구

尹福永 전북대학교 2003 국내석사

PATR 1 Formulation Design and Bioavailability Assessment of SMEDDS Formulation of Simvastatin Simvastatin, a highly effective cholesterol-lowering agent, has been widely used for the treatment of hypercholesterolemia. As all lactone prodrug administered orally, it hydrolyzes in vivo to simvastatin acid, which a potent inhibitor of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase. This enzyme catalyzes the conversion of HMG-CoA to mevalonate, which is an early and rate-limiting step in the biosynthesis of cholesterol. Simvastatin, a white to off-white, nonhygroscopic, highyl crystalline powder with a melting point of 135-138'C, is practically insoluble in water and poorly absorbed from the GI tract. To overcome many problems (poorly water solubility and the oral delivery of such drug is associated with implications of low bioavailability et al.), various formulation strategies are reported in the literature including the use of surfactants, cyclodextrins, nanoparticles, solid dispersions, micronization, lipids, and permeation enhancers. In order to improve the bioavailability efficiency of simvastatin, several ways have been explored: freezing mill, spray dry and alginate beads. Much attention has been paid to the application of microemulsions as drug delivery systems. Because of their high solubilizing capability, thermodynamic stability and spontaneously formation by simple mixing of the various components. Their advantages over conventional emulsions are their stability and ease of manufacture. SMEDDS are isotropic mixtures of an oil, surfactant, cosurfactant, and drug. They form fine oil-in-water emulsions when introduced into aqueous media under mild agitation. The digestive motility of the stomach and intestine provide the agitation necessary for self-emulsification in vivo. The spontaneous formation of an emulsion upon drug release in the GI tract advantageously presents the drug in a solubilised form, and the small droplet size provides a large interfacial surface area for drug absorption. For selecting a suitable self-emulsifying vehicle, it is important to assess: (a) the drug solubility in various components; (b) the area of self-emulsifying region in the phase diagram; and (c) droplet size distribution following self-emulsification. Various types of self microemulsifying formulations were prepared using four types of oil (Capryol 90, Lauroglycol 90, Labrafil M 1944 CS and Labrafil M 2125), two surfactants (Cremophor EL and Tween 80), and three cosurfactants (Carbitol, PEG 400 and propylene glycol). The efficiency of emulsification was studied using a laser diffraction size analyzer to determine particle size distributions of the resultant emulsions. The objectives of the present study were to develop and characterize SMEDDS of simvastatin using propylene glycol monocaprylate (Capryol � 90) as solubilizers, polyoxyl 35 castor oil (Cremophor^� EL) as surfactants and diethylenglycol monoethyl ether (Carbitol) and to assess their bioavailability in beagle dogs. The SMEDDS was optimized by the solubility of simvastatin and the microemulsion existence range after the preparation of microemulsion with varying compositions of Capryol^� 90 and S/CoS mixtures (Cremophor^� EL as surfactants (S) and the combination of Carbitol as cosurfactant (CoS)). The microemulsion existing range is increased proportional to the ratio of S/CoS, however, it decreased remarkable the solubilisity of drug. SMEDDS is the mixtures of oils, surfactants, and cosurfactants, which emulsify under conditions of gentle agitation, similar to those which would be encountered in the gastro-intestinal (GI) tract. Optimized formulations selected for bioavailability assessment were Carpryol 90 (40%), Cremophor EL (30%) and Carbitol (30%). SMEDDSs containing simvastatin 20 mg were compared to a conventional simvastatin tablet (Zorcoa^� , 20 mg/tab) by the oral administration as prefilled hard gelatin capsules to fasted beagle dogs for in vivo study. The area under the serum concentration-time curve from time zero to the last measured time in plasma, AUC_(0→24h), was significantly greater in SMEDDS, suggesting that bioavailability increase 158.90% and 142.85% by the SMEDDS-D form, SMEDDS-H form, respectively. The self-microemulsifying formulations of simvastatin afforded the improvement in absolute oral bioavailability relative to previous data of simvastatin tablet formulation. PART 2 Formulation Design and Bioavailability Assessment of SMEDDS Formulation of Lovastatin Poorly water solubility may be the harbinger of poor oral absorption, profound food effects, site-specific absorption, and extreme sensitivity to salt or polymorphic form, formulation composition, or process variables. The suitability of formulating with organic solvents, oils and emulsions, surfactant systems, complexing agents and even particle size reduction to submicron size then may be evaluated within the context of known properties of the compound. The potential for lipidic SMEDDS to improve the oral bioavailability of a poorly absorbed was investigated through many studies within the past decade. The use of lipid formulations to solubilize drugs can provide the means to delivery insoluble agents via either injectable or oral routes. Lipid-based vehicles are typically considered when the property responsible for the poor aqueous solubility of a given compound is its hydrophobicity. The physicochemical properties of these molecules generally dictate that their dissolution in the gastrointestinal (GI) tract is poor and in many cases limits the extent of drug absorption, oral bioavailability and consequently clinical utility. Lovastatin is a kinds of cholesterol-lowering drugs that are potent inhibitors of the enzyme HMG-CoA reductase. This enzyme is responsible for the conversion of HMG-CoA to mevalonate, which is the major rate-limiting step in the synthesis of cholesterol. After oral administration, lovastatin is hydrolyzed to the active β -hydroxy acid form and produce significant lowering of serum cholesterol in normal human volunteers and in patients with heterozygous familial hypercholesterolemia. Lovastatin is isolated from a strain of Aspergillus terreus and a white, nonhygroscopic crystalline powder that is insoluble in water and sparingly soluble in alcohol and acetonitrile. The absorption of lovastatin in gastrointestial is averaged 30% of oral dose and its serum concentration through systemic circulation is less than 5%. Optimized formulations selected for bioavailability assesment were transqutol, polyethylene glycol, propylene glycol, dimethylether isosorbide, and propylene glycol monocaprylate (Capryol^� 90) as solubilizers and polyoxyl 35 castor oil (Cremophor^� EL) as a surfactant. The multi-component delivery systems were optimized by evaluating their ability to self-emulsifying when introduced to an aqueous medium and gentle agitation, and by determination of particle size of the resulting emulsion. The potential for SMEDDS to improve the oral bioavailability of poorly absorbed, hypercholesterolemia drug (lovastatin) was investigated in fasted beagles by the oral administration. The area under the serum concentration-time curve from time zero to the last measured time in plasma, AUC_(0→24h), was significantly greater in SMEDDS, suggesting that bioavailability increase 130% and 192% by the SMEDDSs, respectively. The self-emulsifying formulations of lovastatin afforded the improvement in absolute oral bioavailability relative to previous data of lovastatin tablet formulation. These data indicate the utility of dispersed self-microemulsifying formulations for the oral delivery of lovastatin and potentially other poorly absorbed drugs.

공단지역에서 유해화학물질 누출 시 ALOHA와 CALPUFF 모델을 이용한 영향평가

윤복영 경북대학교 대학원 2015 국내박사

The development and diversification of industries brought constant increases in chemical uses. New chemicals of 400 types enter the domestic market every year, and serious chemical accidents has been consistently reported. Therefore it is imperative to plan scientific and systematic management of chemicals. Ulsan is known as the industrial powerhouse with the largest petrochemical complex in the nation created in 1962 and more than 1,100 of manufacture businesses are intensively placed in. Thus, there is high probability of a chemical accident because of intensive areas and aging facilities. Accidental releases of hazardous chemicals definitely impact on industry workers, as well as residents, crops and livestock near the site of the accident. Therefore scientific estimation of potentially affected area of chemical accidents and a study of behavior tips are required. The purpose of this study was to estimate the damage range by releases of hazardous chemicals around the Ulsan petrochemical complex using ALOHA and CALPUFF models. Hydrogen fluoride (HF), hydrogen chloride (HCl) and acrylonitrile (CH2CHCN) were applied for dispersion modelling, which were selected from statistical analyses of chemicals using in Ulsan petrochemical industry. ALOHA is available to conduct relatively rapid simulation of the damage range with consideration of the seasons, influencing factors and case date. CALPUFF simulate dispersion behaviors of hazardous chemical releases based on weather condition and geographical feature and decay time points. The damage ranges of each chemicals were determined by level of concern of three chemicals was determined based on ERPG (emergency response planning guidelines for air contaminants) which is utilized by Korea occupational safety & health agency (KOSHA). As a result of ALOHA simulation, a separation distance was relatively larger in autumn season. Damage range was correlated with each influencing factors such as cloud amount, the amount of leakage and the time of leakage, and it was relatively larger at the night-time. Furthermore, it was found that weather conditions and geographical features at the leakage point were the most significant factors of CALPUFF simulation. It is expected that these results are utilized as scientific bases to establish reasonable security plans to minimize residents’ damages from the chemical releases. 산업의 다변화로 화학물질 사용은 지속적으로 증가하고 있으며, 다른분야에 비해 빠르게 성장하고 있지만 매년 각종 화학사고로 인해 체계적인 관리에 대한 필요성이 증대되고 있다. 국내 산업단지의 대표적인 누출사례인 구미공장 불산 누출사고는 공장 근로자 뿐만 아니라 인근지역까지 확산되어 농작물과 가축 그리고 인근주민에게 피해가 발생하여 대규모 화학사고에 대한 대책 수립이 요구되고 있다. 특히 울산은 국가산업단지와 석유화학단지가 밀집되어 있고 조성시기가 가장 오래된 산업단지가 있는 곳으로 각별한 주의가 필요한 지역이다. 따라서 유해화학물질 누출사고 발생시 확산 모델링을 통해 초기이격거리를 산정하여 영향범위를 예측하고자 하였다. 누출시나리오는 울산의 산업단지에서 불화수소와 염화수소 그리고 아크릴로니트릴이 누출되었을 경우 울산의 기상과 지형 자료를 이용하여 누출영향범위를 평가하였다. 누출영향평가는 ALOHA와 CALPUFF 모델을 이용하였다. ALOHA 모델 분석은 계절별 영향인자별 분석 등 민감도 분석과 사례일 분석을 통해 누출지점에서의 피해영향범위를 분석하였다. CALPUFF의 경우 누출지점의 기상과 지역적 특성을 고려한 시각별 이격거리 변화를 분석하였다. 대상물질의 우려농도기준은 ERPG(emergency response planning guidelines for air contaminants) 기준을 적용하였다. ALOHA를 이용한 분석에서 계절별 분석은 가을에 이격거리가 가장 크게 나타났으며, 영향인자별 분석은 운량, 풍속, 누출량 그리고 누출시간대가 영향범위와 큰 상관성이 있었다. 이러한 민감도 분석을 바탕으로 사례일을 선정 분석하였다. CALPUFF를 이용하여 누출사고시 이격거리와 소멸시기를 확인하였고 지역의 풍향과 풍속 그리고 산지지형 등의 영향으로 대상물질의 거동이 상이하게 나타나는 것을 알 수 있었다. 누출영향평가 결과는 석유화학단지에 누출사고시 합리적인 안전대책을 수립할 수 있는 기초자료로 이용될 수 있을 것이다.