• Journal of Pharmaceutical Investigation
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• 제28권1호
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• pp.51-57
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• 1998

Tetracycline lyogel ointment consisting of hydroxy ethyl cellulose(HEC) in glycerin and Eudragit RS 100 in triacetin were prepared and then release characteristic were investigated. The physical properties of lyogel ointment such as viscosity, particle size and microscopic structures were also evaluated. The microscopic structures showed that lyogel particles containing drug were dispersed in the triactin solution. The release rate of drug from lyogel ointment as a function of HEC was not changed. However the release rate was significantly decresed when the amount of Eudragit RS 100 and triacetin in lyogel ointment was increased. The viscosity and weight fraction in external phase of lyogel ointment influenced the release rate. The current studies suggest that the release rate of drug can be controlled by changing of lyogel ointment compositions.

• Archives of Pharmacal Research
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• 제28권4호
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• pp.493-501
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• 2005

Effect of solvents on physical characteristics and release characteristics of monolithic acetaminophen (APAP) hydroxypropylmethylcellulose (HPMC) matrix granules and tablets were examined. Various types and amounts of solvents were employed for granulation and coating. APAP and other excipients were mixed and were then wet-granulated in a high-speed mixer. The dried granules were then directly compressed and film-coated with low viscosity grade HPMC. As the amount of water increased, the size of granules also increased, showing more spherical and regular shape. However, manufacturing problems such as capping and lamination in tableting occurred when water was used alone as a granulating solvent. The physical properties of HPMC matrix granules were not affected by the batch size. The initial release rate as well as the amount of APAP dissolved had a tendency to decrease as the water level increased. Addition of nonaqueous solvent like ethanol to water resulted in good physical properties of granules. When compared to water/ethanol as a coating solvent, the release rate of film-coated HPMC matrix tablets was more sensitive to the conditions of coating and drying in methylene chloride/ethanol. Most of all, monolithic HPMC matrix tablet when granulated in ethanol/water showed dual release with about $50\%$ drug release immediately within few minutes followed by extended release. It was evident that the type and amount of solvents (mainly water and ethanol) were very important for wet granulation and film-coating of monolithic HPMC matrix tablet, because the plastic deforming and fragmenting properties of material were changed by the different strengths of the different solvents.

• Macromolecular Research
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• 제16권1호
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• pp.45-50
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• 2008

This study examined the swelling behavior and in vitro release of a model drug, tetracycline-HCl, from alginate and alginate-polyaspartate (Alg-PASP) composite gel beads. The alginate and Alg-PASP composite beads were prepared using an ionic crosslinking method with aqueous $Ca^{2+}$. Their microporous morphology was observed by scanning electron microscopy. The swelling ratio of the beads in different media varied according to their composition, cross-linking density ($Ca^{2+}$ concentration), and pH of the aqueous medium. The in vitro release experiment of the tetracycline-HCl encapsulated beads in different media suggests that the release of the drug is governed mainly by the swelling properties of the polymer network. The presence of PASP was found to significantly influence the swelling properties and drug release profile.

• International Journal of Automotive Technology
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• 제4권3호
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• pp.125-133
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• 2003

Several models for the evaluation of Gross Heat Release from the internel combustion engine (ICE) are often used in literature. One of these is the First Law - Single Zone Model (FL-SZM), derived from the First Law of Thermodynamic. This model present a twice advantage: first it describes with accuracy the physic of the phenomenon (charge heat release during the combustion stroke and heat exchange between gas and cylinder wall); second it hat a great simplicity in the mathematical formulation. The evaluation of Heat Release with the FL-SZM is based on pressure experimental measurements inside the cylinder, and ell the assumption of several parameters as the specific heat ratio, wall temperature, polytropic exponent for the motored cycle evaluation, and many others. In this paper the influence of gases thermodynamic properties on Cross Heat Release has been esteemed. In particular the influence of an appropriate equation for k=k(T) (specific heat ratio vs. temperature) which describes the variations of gases thermodynamic properties with the mean temperature inside the cylinder has been evaluated. This equation has been calculated by new V order Logarithmic Polynomials (VoLP), fitting experimental gases properties through the least square methods.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.434-435
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• 2003

Physicochemical properties of a polymer surface significantly affect adhesion, wetting, and dyeing properties. In recent years, low temperature plasma technology has been widely used for surface modification of polymers. Surface fluorination by low temperature plasma treatment has been employed to improve the water and oily repellency of textile fabrics. However, very few results have been reported on soil release properties of the oxygen plasma treated textile fabrics. (omitted)

• 한국토양비료학회지
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• 제44권4호
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• pp.545-550
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• 2011

Urea intercalated into montmorillonite (MT) exhibits remarkably enhanced N use efficiency, maintaining its fast effectiveness. This study dealt with the release property of urea from metal-urea-clay hybrid with MT (MUCH) under continuous-flow conditions and the cumulative impacts of its successive application on physicochemical properties of soils. Releases of urea were completed within 4 hrs under continuous-flow condition regardless of the types and the leaching solutions. However, urea release property was significantly affected by both the form of fertilizer and the presence of electrolytes in solution. The fast release property of urea from MUCH in continuous-flow condition was not significantly affected by soil properties such as soil pH and soil texture. In addition, its successive application did not lead to any noticeable change in soil physicochemical properties, water stable aggregate rate, water holding capacity and cation exchange capacity in both sandy loam and clay loam soils. Therefore, this study strongly supported that urea intercalated into MT could be applied as fast-effective N fertilizer, in particular for additional N supply.

• Journal of Pharmaceutical Investigation
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• 제21권4호
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• pp.237-245
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• 1991

Matrix type silicone rubber devices were designed for long-term implantable drug delivery system. Release controlling agents (RCA), i.e., polypropylene glycol, polyethylene glycol, were employed to control drug release from the devices. The release rate of drug from RCA dispersed silicone matrices was mainly dependent on hydrophilicity-hydrophobicity of drug and RCA. In the case of hydrophilic drug, the release from the RCA dispersed matrix was regulated by swelling kinetics. Especially when the relatively hydrophobic polypropylene glycol was used, swelling control mechanism induced zero-order release kinetics. Whereas, the release of hydrophobic drug was resulted from partition mechanism. The effect of RCA was to increase drug diffusivity.

• 한국화재소방학회논문지
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• 제25권6호
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• pp.190-195
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• 2011

에틸렌-프로필렌 디엔 단량체/폴리프로필렌에 바탕을 둔 에틸렌-프로필렌 디엔 단량체, 폴리프로필렌, 산화아연, 스테아르산, 그리고 클레이의 효과에 대하여 연소성을 조사하였다. 에틸렌-프로필렌 디엔 단량체/폴리프로필렌/클레이 나노복합체는 성형 후 콘칼로리미터(ISO 5660-1)를 이용하여 연소시험을 하였다. 그 결과 나노복합체는 에틸렌-프로필렌 디엔 단량체/폴리프로필렌 단독 조성에 비하여 최대열방출률을 감소시켰다. 이에 반하여 고무 연화제로 사용된 스테아르산은 자체의 연소성에 의하여 평균열방출률을 증가시켰다.

• 접착 및 계면
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• 제6권4호
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• pp.1-6
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• 2005

본 실험에서는 화학적 표면처리된 탄화규소의 첨가가 탄화규소(SiC)/에폭시 복합재료의 critical strain energy release rate mode II ($G_{IIC}$) 특성에 미치는 영향에 대하여 알아보았으며, 표면처리된 SiC의 표면특성은 산 염기도와 FT-IR을 사용하여 알아보았다. 또한 복합재료의 기계적 계면물성은 $G_{IIC}$를 통하여 알아보았다. 실험결과, 산성 용액으로 표면처리한 SiC (A-SiC)의 표면 산도가 염기성(B-SiC) 또는 표면처리 하지 않은 SiC (V-SiC)보다 높으며, $G_{IIC}$의 크랙저항 특성은 A-SiC가 향상되었는데, 이러한 결과는 SiC 충전재와 에폭시 수지간의 분자간 계면결합력의 향상 때문으로 판단된다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2014년도 춘계학술대회
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• pp.260-261
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• 2014

In the present study analysed the physico chemical properties and distribution of heavy metal and also analysed the changes of heavy metal distribution by resuspension and properties of heavy metal release into sea water. From the experimental result showed sediment resuspension plays an important role in the release of heavy metals in coastal environment. Heavy metal release percentage was high in different mixing time of resuspension and different amounts of sediment due to resuspension of particulate matter.