• Title/Summary/Keyword: Sold dispersion

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Preparation and In Vitro Test of Sold Dispersion using Acyclovir and Water Soluble Polymer (아시클로비어와 수용성 고분자를 이용한 고체분산체 제조 및 생체외 방출)

  • Ahn, Yong-San;Lee, Ha-Young;Hong, Keum-Duck;Jung, Sung-Beum;Cho, Sun-Hang;Rhee, John-Moon;Lee, Hai-Bang;Khang, Gil-Son
    • Journal of Pharmaceutical Investigation
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    • v.34 no.3
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    • pp.169-176
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    • 2004

  • Acyclovir(ACV) is an important antiviral drug used extensively against infections caused by herpes viruses, especially herpes simplex and varicella zoster. Because of high crystallinity and large particle size, solubility of intact ACV is very low in water(1.3 mg/ml). The goal of this work is to enhance the solubility of ACV. To make solid dispersion, Polyethyleneglycol, Hydroxyprophylmethylcelluose and Polyvinylpyrrolidone were used as polymer carriers in this work. Polymer carriers and drug were dissolved in acetic acid. And then spray drying method and freeze drying method were used as solvent extraction. Morphology, crystallization and functional group were characterized using SEM, XRD and FT-IR. The result of in vitro test showed the sample using PVP as polymer carrier had higher dissolution rate(up to 466%) than intact ACV.

  • https://doi.org/10.4333/KPS.2004.34.3.169 인용 PDF KSCI

Effect of Types and Mixing Ratios of Water-Soluble Polymers on In Vitro Release Profile of Sold Dispersion for Acyclovir (아시클로비어 고체분산체의 용해도에 대한 수용성 고분자의 종류 및 배합 비율에 따른 효과)

  • Ahn, Yong-San;Lee, Ha-Young;Hong, Keum-Duck;Jung, Sung-Beum;Cho, Sun-Hang;Rhee, John M.;Lee, Hai-Bang;Khang, Gil-Son
    • Journal of Pharmaceutical Investigation
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    • v.34 no.4
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    • pp.289-297
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    • 2004

  • Acyclovir (ACV) is one of the most effective and selective agents against viruses of the herpes group. Because of low solubility, bioavailability of ACV has shown below 30% with oral dosage form. In our previous study, we reported that the fabrication of solid dispersion of ACV was possible and the solid dispersion of ACV and PVP was the most useful in all samples. In this study, we examined the effect of mixture ratio of polymers (PEG and PVP) to ACV. Solubility of ACV was dramatically increased up to 25 mg/ml in $80^{\circ}C$ distilled water. So water was used as a solvent to eliminate problem of residual solvent. Spray drying method was used for the solid dispersion of ACV as solvent extraction. Different scanning calorimeter was used to check degradation of drug. Polymer carriers were PEG 6,000 and PVP. In summary, ACV-PVP (1:3) showed the best solubility in distilled water.

  • https://doi.org/10.4333/KPS.2004.34.4.289 인용 PDF KSCI

The Effect of Solvents on Sold Dispersion of Ipriflavone with Polyvinylpyrrolidone In Vivo

  • Jeong, Je-Kyo;Ahn, Yong-San;Moon, Byung-Kwan;Choi, Myung-Kyu;Khang, Gil-Son;Rhee, John-M.;Lee, Hai-Bang
    • Journal of Pharmaceutical Investigation
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    • v.35 no.1
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    • pp.1-5
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    • 2005

  • ABSTRACT -Ipriflavone is a synthetic flavonoid derivate that improves osteoblast cell activity inhibiting bone resorption. In order to improve the bioavailability, solid dispersions of ipriflavone with PVP (poly-N-vinylpyrrolidone, MW=40,000 g/mole) were prepared by a spray-drying method. During the manufacturing of solid dispersion, various solvents [ethanol (EtOH), acetonitrile, methylene chloride and cosolvent-EtOH:acetone=1:1] were used to dissolve the ipriflavone and PVP. Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were used to evaluate the physicochemical interaction between ipriflavone and PVP. Particle size, crystallinity and the area of the endotherm $({\Delta}H)$ of solid dispersed ipriflavone using the acetonitrile as solvent were much smaller than those of the other preparation types. Bioavailability of ipriflavone in vivo was changed by solvents. When considering the result of in vivo test, solid dispersion of ipriflavone using the acetonitrile as solvent showed the best choice.

  • https://doi.org/10.4333/KPS.2005.35.1.001 인용 PDF KSCI

Initial Operation Case Study on KTX Special Class (KTX 특정(조건부) 할인상품 운영에 관한 사례 연구)

  • Han, Eun-Young;Ju, Sang-Hwa
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.758-762
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    • 2007

  • Revenue management is a new approach method to solve the problem of supply and demand, and one of fields which is diffused quickly at the service enterprise to use perishable-asset like the transportation business. It is based on multiple fare policy that discount charge reservation should be received if the benefit value of current discount fare is more than expected profit of the normal fare reservation it will be able to occur in future when suitable goods is sold to the customers at discount fare, at the time they want, and at assigned seat by controlling supply and demand from market. In this research, I will review on initial operation case for special class goods that the seat which is limited is assigned at some of train and portion of KTX for demand dispersion and new demand creation at peak time, put a limit in purchase conditions, and provides discounted fare. I will also try to find implication for strategic operation.

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The Exploratory Study of the Dynamic Price Changing under the On-line Context (온라인 환경 하에서 제품가격의 동적인 변화에 대한 탐색적 연구)

  • Na, Kyung Soo;Son, Young Seok
    • The Journal of the Korea Contents Association
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    • v.20 no.2
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    • pp.511-521
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    • 2020

  • The purpose of this study is to research the effects of the same brand item sold online at different prices. To that end, the exploratory study is focused on four factors that influence price dispersion online is suggested. First, the products are divided into utilitarian products and hedonic products in line with the product concept, and laptops, washing machines are included in the utility concept products. Also the backpacks and sneakers are included in the hedonic concept products. A total of 400 effective objectives were selected and analyzed for each concept products, 200 objectives. The research analysis revealed that the price dispersion is significant relationship with an average price, the highest price, the lowest price, the year of release, the number of retailers, and the number of reviews in case of the utility concept product. On the contrary, in case of hedonic concept products, average price, highest price, lowest price, year of release, retailer, and reviews and ratings is found to be positively related to price dispersion. Based on these results, theoretical and practical implications are discussed about the influence price dispersion on marketing.

  • https://doi.org/10.5392/JKCA.2020.20.02.511 인용 PDF KSCI HTML

Experimental Study of Tribological Properties According to Oil Grade (오일 등급에 따른 트라이볼로지 특성의 관한 실험적 고찰)

  • Lee, Jong-Ho;Seo, Kuk-Jin;Hwang, Youn-Hoo;Han, Jae-Ho;Kim, Dae-Eun
    • Tribology and Lubricants
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    • v.37 no.6
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    • pp.246-252
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    • 2021

  • Among the engine components of an internal combustion engine, the valve train is a series of systems that supply intake gas to the combustion chamber and operate intake and exhaust valves that discharge exhaust gas. If excessive wear occurs in the valve train system, the suction and exhaust valves do not open and close on time, which leads to abnormal combustion and exhaust gas. In this study, we conduct experiments and analyses on friction and wear characteristics of the valve train system. Moreover, we experimentally study the correlation between the pinball and pinball cap on engine oil lubrication, friction experiment, wear amount analysis, and surface analysis. Specifically, we experiment using Ball on reciprocating tribo-tester and apply commercial engine oil sold on the market engine oil. We construct the experimental conditions for each new oil and oil. Accordingly, the completed specimen was subjected to a confocal microscope to check the wear volume, observe the surface of the specimen, and confirm the elemental components using a scanning microscope (SEM) and an energy dispersion X-ray spectrometer (EDS). Through this experiment, we analyze the friction and wear characteristics of valve train components according to engine oil grade, and the obtained data serve as an effective engine oil management method.

  • https://doi.org/10.9725/kts.2021.37.6.246 인용 PDF KSCI HTML

The Study on the On-line Sales Fitness of Small-sized Companies' Product Categories by the Integration of SEC and FCB Framework (SEC와 FCB골격 의 통합적 접근방법을 통한 중소기업 제품군의 인터넷 판매 적합성에 대한 연구)

  • Park, Seong-Yong
    • Journal of Global Scholars of Marketing Science
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    • v.16 no.3
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    • pp.169-189
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    • 2006

  • The product categories that can be sold on-line are expanding. It is interesting to see which product categories have more sales possibilities on internet. Small-sized firms' products have low distribution coverage, low brand recognition, bigger dispersion in the perception on the values which consist of quality vs. price, and higher possibilities of perceived purchase risks. Since on-line shopping is supposed to provide opportunities to small-sized firms that have low distribution and brand power, it is quite necessary to evaluate the fitness of on-line sales for small-sized firms' product categories. There are virtually no research studies on the on-line sales for small-sized firms' product categories. In this study, based on the integration of SEC, FCB, and related concepts, we develop new theoretical framework and test the fitness of on-line sales for small-sized firms' product categories by conducting empirical analysis. The empirical results on 17 product categories show that SEC, FCB, purchase risks, brand factors are somewhat related. Unlike previous studies, since the fitness of SEC and on-line sales are not clearly shown, we need to consider those problems within inter-related multiple frameworks. That is, it is necessary to evaluate the fitness of on-line sales after defining the product categories within the integrated multiple frameworks rather than within the single framework.

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The Impact of Market Environments on Optimal Channel Strategy Involving an Internet Channel: A Game Theoretic Approach (시장 환경이 인터넷 경로를 포함한 다중 경로 관리에 미치는 영향에 관한 연구: 게임 이론적 접근방법)

  • Yoo, Weon-Sang
    • Journal of Distribution Research
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    • v.16 no.2
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    • pp.119-138
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    • 2011

  • Internet commerce has been growing at a rapid pace for the last decade. Many firms try to reach wider consumer markets by adding the Internet channel to the existing traditional channels. Despite the various benefits of the Internet channel, a significant number of firms failed in managing the new type of channel. Previous studies could not cleary explain these conflicting results associated with the Internet channel. One of the major reasons is most of the previous studies conducted analyses under a specific market condition and claimed that as the impact of Internet channel introduction. Therefore, their results are strongly influenced by the specific market settings. However, firms face various market conditions in the real worlddensity and disutility of using the Internet. The purpose of this study is to investigate the impact of various market environments on a firm's optimal channel strategy by employing a flexible game theory model. We capture various market conditions with consumer density and disutility of using the Internet.

    shows the channel structures analyzed in this study. Before the Internet channel is introduced, a monopoly manufacturer sells its products through an independent physical store. From this structure, the manufacturer could introduce its own Internet channel (MI). The independent physical store could also introduce its own Internet channel and coordinate it with the existing physical store (RI). An independent Internet retailer such as Amazon could enter this market (II). In this case, two types of independent retailers compete with each other. In this model, consumers are uniformly distributed on the two dimensional space. Consumer heterogeneity is captured by a consumer's geographical location (ci) and his disutility of using the Internet channel (${\delta}_{N_i}$).
    shows various market conditions captured by the two consumer heterogeneities.
    (a) illustrates a market with symmetric consumer distributions. The model captures explicitly the asymmetric distributions of consumer disutility in a market as well. In a market like that is represented in
    (c), the average consumer disutility of using an Internet store is relatively smaller than that of using a physical store. For example, this case represents the market in which 1) the product is suitable for Internet transactions (e.g., books) or 2) the level of E-Commerce readiness is high such as in Denmark or Finland. On the other hand, the average consumer disutility when using an Internet store is relatively greater than that of using a physical store in a market like (b). Countries like Ukraine and Bulgaria, or the market for "experience goods" such as shoes, could be examples of this market condition. summarizes the various scenarios of consumer distributions analyzed in this study. The range for disutility of using the Internet (${\delta}_{N_i}$) is held constant, while the range of consumer distribution (${\chi}_i$) varies from -25 to 25, from -50 to 50, from -100 to 100, from -150 to 150, and from -200 to 200.
    summarizes the analysis results. As the average travel cost in a market decreases while the average disutility of Internet use remains the same, average retail price, total quantity sold, physical store profit, monopoly manufacturer profit, and thus, total channel profit increase. On the other hand, the quantity sold through the Internet and the profit of the Internet store decrease with a decreasing average travel cost relative to the average disutility of Internet use. We find that a channel that has an advantage over the other kind of channel serves a larger portion of the market. In a market with a high average travel cost, in which the Internet store has a relative advantage over the physical store, for example, the Internet store becomes a mass-retailer serving a larger portion of the market. This result implies that the Internet becomes a more significant distribution channel in those markets characterized by greater geographical dispersion of buyers, or as consumers become more proficient in Internet usage. The results indicate that the degree of price discrimination also varies depending on the distribution of consumer disutility in a market. The manufacturer in a market in which the average travel cost is higher than the average disutility of using the Internet has a stronger incentive for price discrimination than the manufacturer in a market where the average travel cost is relatively lower. We also find that the manufacturer has a stronger incentive to maintain a high price level when the average travel cost in a market is relatively low. Additionally, the retail competition effect due to Internet channel introduction strengthens as average travel cost in a market decreases. This result indicates that a manufacturer's channel power relative to that of the independent physical retailer becomes stronger with a decreasing average travel cost. This implication is counter-intuitive, because it is widely believed that the negative impact of Internet channel introduction on a competing physical retailer is more significant in a market like Russia, where consumers are more geographically dispersed, than in a market like Hong Kong, that has a condensed geographic distribution of consumers.
    illustrates how this happens. When mangers consider the overall impact of the Internet channel, however, they should consider not only channel power, but also sales volume. When both are considered, the introduction of the Internet channel is revealed as more harmful to a physical retailer in Russia than one in Hong Kong, because the sales volume decrease for a physical store due to Internet channel competition is much greater in Russia than in Hong Kong. The results show that manufacturer is always better off with any type of Internet store introduction. The independent physical store benefits from opening its own Internet store when the average travel cost is higher relative to the disutility of using the Internet. Under an opposite market condition, however, the independent physical retailer could be worse off when it opens its own Internet outlet and coordinates both outlets (RI). This is because the low average travel cost significantly reduces the channel power of the independent physical retailer, further aggravating the already weak channel power caused by myopic inter-channel price coordination. The results implies that channel members and policy makers should explicitly consider the factors determining the relative distributions of both kinds of consumer disutility, when they make a channel decision involving an Internet channel. These factors include the suitability of a product for Internet shopping, the level of E-Commerce readiness of a market, and the degree of geographic dispersion of consumers in a market. Despite the academic contributions and managerial implications, this study is limited in the following ways. First, a series of numerical analyses were conducted to derive equilibrium solutions due to the complex forms of demand functions. In the process, we set up V=100, ${\lambda}$=1, and ${\beta}$=0.01. Future research may change this parameter value set to check the generalizability of this study. Second, the five different scenarios for market conditions were analyzed. Future research could try different sets of parameter ranges. Finally, the model setting allows only one monopoly manufacturer in the market. Accommodating competing multiple manufacturers (brands) would generate more realistic results.

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