• Food Science and Biotechnology
• /
• 제18권5호
• /
• pp.1071-1075
• /
• 2009

Allyl isothiocyanate (AI), a volatile compound of mustard, has excellent antimicrobial effects, but its volatility hinders its wide usage as an ingredient of food products. Microencapsulation technique, therefore, was applied for delaying the release time of AI. For delaying the release time of AI, the mustard powder, which contained AI, was microencapsulated with 5% modified starch by using fluidized bed processing. The efficiency of the controlled release of AI at various pH was analyzed by the head space (HS) analysis and solid phase microextraction (SPME) method using gas chromatography (GC). Also, modified starch encapsulated powder was added into kimchi for applying in food industry. As the result, the release time of AI was delayed by microencapsulation with modified starch and the higher pH could be the faster release of AI. Also, the period until the pH values and total acidity of kimchi reached up to 4.5 and 0.6%, which give its malsour taste, was extended by microencapsulation. These results showed that modified starch encapsulated powder could prolong the preservation in food system.

• Journal of Pharmaceutical Investigation
• /
• 제34권3호
• /
• pp.229-254
• /
• 2004

The objective of this study was to scrutinize the rationale of SUPAC-MR and its application in processing postapproval changes to modified release solid oral dosage forms. The types of postapproval changes that were primarily covered with SUPAC-MR included variations in the components and composition, the site of manufacturing, batch size, manufacturing equipment, and manufacturing process. SUPAC-MR defined levels of postapproval changes that the industry might make. Classification of such categories was based on the likelihood of risk occurrence and potential impact of changes upon the safety and efficacy of approved drug products. In most cases, the changes could be classified into 3 levels. It described what chemistry, manufacturing, and control tests should be conducted for each change level. The important tests specified in SUPAC-MR were batch release, stability, in vitro dissolution, and in vivo bioequivalence tests. It then suggested what type of a filing report should be submitted to the FDA for each change level. In general, level 1 changes could be reported in an annual report, whereas level 2 and/or 3 changes could be submitted in changes-being-effected or prior approval supplements. It could be understood that the purpose of SUPAC-MR was to maintain the safety and quality of approved modified release solid oral dosage forms undergoing certain changes. At the same time, it contributed to providing a less burdensome regulatory process with the manufacturers when they wanted to make postapproval changes. European regulatory agencies also implemented SUPAC-like regulations in handling such changes to drug products. Therefore, in this study a recommendation was made for KFDA and the Korean industry to evaluate thoroughly the usefulness of these guidances and regulations in dealing with postapproval changes to modified release solid oral dosage forms.

• Journal of Pharmaceutical Investigation
• /
• 제41권3호
• /
• pp.185-190
• /
• 2011

The purpose of this study was to evaluate the phagocytic uptake of surface modified PLGA microspheres containing ovalbumin (OVA) into dendritic cell. In order to find the most suitable formulation for targeted delivery to antigen presenting cells (APC), OVA was encapsulated by a double emulsion solvent evaporation method with three PLGA microspheres (PLGA 50:50, PLGA 75:25 and PLGA 85:15) and two surface modified microspheres by chitosan and sodium dodecyl sulfate (SDS). Physicochemical properties were evaluated in terms of size, zeta potential, encapsulation efficiency, different scanning calorimeter (DSC), x-ray diffraction, morphology, and OVA release test from microspheres. Phagocytic activity was estimated using dendritic cells and analyzed by fluorescence activated cell sorter (FACS). The result showed that zeta potential of PLGA particles was changed to positive by the chitosan modification. The release profile of chitosan modified PLGA microspheres exhibited sustained release after initial burst. The chitosan modified microspheres had higher phagocytic uptake than the other microspheres. Such physicochemical properties and phagocytic uptake studies lead us to conclude that chitosan modified microspheres is more suitable formulation for the targeted delivery of antigens to APC compared with the other microspheres.

• 한국농공학회논문집
• /
• 제56권5호
• /
• pp.1-9
• /
• 2014

The DIROM (Daily Irrigation Reservoir Operation Model) was modified to estimate amounts of water release from reservoirs, considering customary irrigation water management practices, such as water supply for puddling and transplanting paddy rice from seeding beds and mid-season drainage. The applicability of the modified model was investigated by simulating amounts of water release from three study reservoirs: Hwamae, Ogi, and Doya Reservoirs. In terms of annual amounts of water release, the relative errors between the observed and simulated values in 2012 and 2013 ranged -26.20 % to 10.28 % and 4.90 % to 30.06 %, respectively; in case of reservoir water levels, the RMSE values ranged 0.45 m to 1.34 m and 0.40 m to 1.27 m, respectively. Also, it was revealed that the model provided better simulation results for monthly water releases than the original model. In addition, the model presented better performance in simulating 10-day amounts of water release from April to June. However, the model had still significant errors in the simulation results from July to September because the reservoirs were practically operated to adapt to water management circumstances. Finally, it is concluded that the modified DIROM can estimate the amounts of water release from reservoirs, reflecting irrigation water management customs in paddy-field districts. To achieve higher prediction accuracy of the model, it is necessary to incorporate practical reservoir operation rules into the model.

• Restorative Dentistry and Endodontics
• /
• 제40권3호
• /
• pp.209-215
• /
• 2015

Objectives: The aim of this study was to evaluate the fluoride release of conventional glass ionomer cements (GICs) and resin-modified GICs. Materials and Methods: The cements were grouped as follows: G1 (Vidrion R, SS White), G2 (Vitro Fil, DFL), G3 (Vitro Molar, DFL), G4 (Bioglass R, Biodinamica), and G5 (Ketac Fil, 3M ESPE), as conventional GICs, and G6 (Vitremer, 3M ESPE), G7 (Vitro Fil LC, DFL), and G8 (Resiglass, Biodinamica) as resin-modified GICs. Six specimens (8.60 mm in diameter; 1.65 mm in thickness) of each material were prepared using a stainless steel mold. The specimens were immersed in a demineralizing solution (pH 4.3) for 6 hr and a remineralizing solution (pH 7.0) for 18 hr a day. The fluoride ions were measured for 15 days. Analysis of variance (ANOVA) and Tukey's test with 5% significance were applied. Results: The highest amounts of fluoride release were found during the first 24 hr for all cements, decreasing abruptly on day 2, and reaching gradually decreasing levels on day 7. Based on these results, the decreasing scale of fluoride release was as follows: G2 > G3 > G8 = G4 = G7 > G6 = G1 > G5 (p < 0.05). Conclusions: There were wide variations among the materials in terms of the cumulative amount of fluoride ion released, and the amount of fluoride release could not be attributed to the category of cement, that is, conventional GICs or resin-modified GICs.

• International Journal of Concrete Structures and Materials
• /
• 제18권3E호
• /
• pp.213-219
• /
• 2006

Modified singular fracture process zone(S-FPZ) model is proposed in this paper to determine a fracture criterion for continuous crack propagation in concrete. The investigated fracture properties of the proposed fracture model are strain energy release rate at a micro-crack tip and the relationship between crack closure stress(CCS) and crack opening displacement(COD) in the FPZ. The proposed model can simulate the actual fracture energy of experimental results fairly well. The results of the experimental data analysis show that specimen geometry and loading condition did not affect the CCS-COD relation. However, the strain energy release rate is a function of not only specimen geometry but also crack extension. The strain energy release rate remained constantly at the minimum value up to the crack extension of 25 mm, and then it increased linearly to the maximum value. The maximum fracture criterion occurred at the peak load for specimens of large size. The fracture criterion remained at the maximum value after the peak load. The variation of the fracture criterion is caused by micro-cracking and micro-crack localization. The fracture criterion of strain energy release rate can simply be the size effect of concrete fracture, and it can be used to quantify the micro-cracking and micro-crack localizing behavior of concrete.

• Archives of Pharmacal Research
• /
• 제16권2호
• /
• pp.123-128
• /
• 1993

The surface of cyarabine-entrapped albumin microspheres, the surface modified albumin microspheres hsowed remakably incrased hydrophilicity, good dispersability in aqueous medium and reduced aggregation during storage which met the requirements of injectable drug carriers in acqueous vehicle. In vitro cytarabine release from hydrophilic albumin microspheres (HAM) was a function of the cytarabine to albumin ratio, whereas no significant difference in the releasing capacity was obnserved between surface modified HAM within the small size range$(2\;to\;5\mu{m)}$ studied. HAM containing 15-23% drug were gradually degraded by protease and continuously released up to 60% of the total entrapped cytarabine for 6h. These results thus suggest that HAM is a suitable cytarabine carrier which may be injected intraveneously with the benefits of a reduced risk of blood embolism induced by aggregates and prolonged cytarabine release.

• 폴리머
• /
• 제28권1호
• /
• pp.59-66
• /
• 2004

온도에 의존하여 졸-젤 전이를 나타내는 온도민감성 리포솜을 함유하는 폴리 N-이소프로필아크릴아마이드 젤을 제조하였다. 온도민감성 리포솜의 표면은 3$0^{\circ}C$에서 하한임계용액온도를 나타내는 N-이소프로필아크릴아마이드와 옥타데실아크릴레이트의 공중합체를 이용하여 변형시켰다. 표면이 변형된 온도민감성 리포솜을 폴리 N-이소프로필아크릴아마이드 수용액에 혼합하였다. 혼합용액을 하한임계용액온도 이상으로 가열했을 때 물리적으로 가교결합이 이루어진 젤의 형태가 이루어지며, 이때 온도 민감성 리포솜이 함유된 폴리 N-이소프로필아크릴아마이드 젤이 만들어진다. 온도민감성 리포솜으로부터 약물의 방출은 형광강도를 측정하여 결정하였다. 폴리 N-이소프로필아크릴아마이드 젤 내부의 온도민감성 리포솜으로부터 약물의 방출은 온도가 증가할수록 지속적인 방출을 나타내었다.

• 대한의생명과학회지
• /
• 제13권3호
• /
• pp.175-182
• /
• 2007

In vitro ciprofloxacin (CFX)-release study and bioassay using microorganisms were performed to estimate the retention of the antimicrobial activity of the CFX-incorporated central venous catheters (CFX-CVCs). The release experiments were carried out under the optional CFX-release conditions to mimic the in vivo environment. The release of CFX experienced an initial burst followed by a slow and steady matrix-diffusion controlled release. The 1.0CP (polyurethane catheter containing 1.0% (w/w) of CFX) under dynamic condition showed a near zero-order CFX release profile, which is beneficial for the long-tenn antimicrobial activity. The modified Kirby-Bauer method was performed employing S. aureus and E. coli to evaluate the retention of antimicrobial activity of the catheters retrieved from the release experiments. The 1.0CP showed the long-term antimicrobial activity (${\geq}\;21$ days) against both S. aureus and E. coli. These results indicate that 1.0CP is useful as a long-tenn indwelling CVC.

• Korean Chemical Engineering Research
• /
• 제58권3호
• /
• pp.438-449
• /
• 2020

본 연구는 화학 및 석유화학 플랜트 등의 장치산업에서 사업장 외부로 유해화학물질이 누출·확산되어 발생할 수 있는 배상책임 위험도에 대한 산정 방식을 개선하고자 하였다. 이를 위해 환경부 사고대비 물질(14종)에 대해 누출·확산 시뮬레이션, 화학물질 누출사고 사례 분석, 식물피해 영향 자료 분석 등을 통하여 화학물질 누출사고 배상책임 위험도와의 상관관계인자를 도출하였고, 도출된 결과를 바탕으로 화학물질 배상 책임 위험도 산정 방법을 수정·보완하였다. 14종의 화학물질의 Probit 값과 EURAM 배상책임 위험도의 상관계수는 -0.526로 나타났고, 수정된 화학물질 누출사고 배상책임 위험도와의 상관계수는 0.319로 상관성이 있는 것으로 분석되었다. 수정된 산정 방법론으로 97종에 대한 배상책임 위험도와 ERPG-2 값의 상관계수는 -0.494로 분석되었고, 이는 기존 배상책임 위험도와의 상관관계보다 약 19배 높은 상관관계를 보였고, 부식위험도 값과의 상관계수는 0.91로 분석되었다. 위험도의 증가와 감소에 영향을 미친 상관관계 인자의 표준화 회귀계수(β) 값은 Corrosion Index (0.713), ERPG-2 (0.400), NFPA_Health Index (0.068) 크기 순서로 도출되었다. 이러한 연구결과는 기존과 신규 화학물질의 합리적인 배상책임 위험도 산정이 가능하게 하고, 사업장에서 정량적인 배상책임 위험관리 지표로 활용하는데 도움이 되리라 판단된다.