• Title/Summary/Keyword: Controlled Release

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STUDY ON HEAT RELEASE RATE BY COMBUSTION IN DIESEL ENGINE (Diesel기관의 연소에 의한 열발생율의 연구)

  • AHN Soo Gil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.8 no.3
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    • pp.150-156
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    • 1975

  • This paper dealt itself with the relation of the heat release rate with crank angle in combustion process by adjusting the injection time, injection amount and engine speed of diesel engine. The result of test were obtained by analyzing indicator diagram of KUBOTA 2LKE diesel engine, where the indicator was used Tertronix oscilloscope. The combustion period of diesel engine is composed of premixed burning time and combustion controlled time. The larger the premixed burning region, the higher efficiency was obtained with the higher maximum pressure than at the time of the normal smooth operation. The longer the combustion controlled time, the lower the maximum pressure than the period of the normal operation, but the efficiency was decreased. The region of premixed burning was principally controlled by injection delay, but combustion controlled time was affected when oxygen and fuel were mixed. Efficiency of engine was increased at the time of earlier injection time under the constant injection amount, and engine speed, but the pressure increasing was observed higher than the efficiency increasing.

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Formulation of a Novel Polymeric Tablet for the Controlled Release of Tinidazole (티니다졸의 제어방출을 위한 새로운 합성고분자성 정제의 조성)

  • Yoon, Dong-Jin;Shin, Young-Hee;Kim, Dae-Duk;Lee, Chi-Ho
    • Journal of Pharmaceutical Investigation
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    • v.29 no.4
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    • pp.349-353
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    • 1999

  • A novel polymeric tablet of tinidazole (TD) was formulated to treat Helicobacter pylori and Giardia lambria more efficiently with reduced hepatotoxicity by controlling the release of TD after oral administration. TD tablets containing various concentrations of either xanthan gum (XG, viscosity enhancer) and/or polycarbophil (PC, mucoadhesive) were prepared by the wet granulation method. In vitro release of TD into pH 2.0 and pH 5.0 buffer solutions was observed at 37°C by using an USP dissolution tester and an UV (313 nm) spectrophotometer. In vivo absorption of TD tablets was investigated in rabbits by measuring the blood concentration of TD after oral administration using a HPLC. Compared to a commercial TD tablet, in vitro release of TD in both pH 2.0 and pH 5.0 buffer solutions significantly decreased as the concentration: of XG or PC in the tablet increased up to 30%. However, when XG and PC was added in combination, TD was completely released in a pH 5.0 buffer solution within 8 hours, whereas the release of TD in pH 2.0 buffer solution significantly decreased. TD in a commercial tablet was rapidly absorbed after oral administration in rabbits. After oral administration of the polymeric tablets that contain both XG and PC, plasma concentration of TD dramatically decreased. Since the oral absorption of TD significantly decreased by the addition of XG and PC in the tablets while TD completely released in a pH 5.0 buffer solution, it was speculated that more TD was retained in the gastrointestinal tract. Thus, it was possible to control the release of TD by changing the content of XG and/or PC in the tablet, thereby manipulating the release rate and the gastrointestinal retention of TD after oral administration in rabbits.

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Preparation and Dissolution Characteristics of Sustained Release Granules Containing Indapamide (인다파마이드가 함유된 서방형 과립의 제조 및 용출 특성)

  • Park, Ji-Seon;Seo, Hui;Kim, Byung-Jin;Jeong, Sang-Young;Shin, Byung-Cheol;Yuk, Sun-Hong;Hwang, Sung-Joo;Cho, Sun-Hang
    • Journal of Pharmaceutical Investigation
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    • v.38 no.2
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    • pp.105-110
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    • 2008

  • Indapamide (4-chloro-N-(2-methyl-1-indolinyl)-3-sulfamoyl-benz-amide) is an oral antihypertensive diuretic agent indicated for the treatment of hypertensive. The diuretic and natriuretic effects are mainly due to the structure of o-chlorobenzenesulfonamide. The objective of this study was to formulate sustained release indapamide granules and assess their formulation variables. Granules were prepared by fluid bed coating method and consist of drug layer and membrane layer. The granules were coated with HPC and ethyl cellulose along with plasticizer dibuthyl sebacate. The release of indapamide depended on the type of Eudragit such as RS and NE 30 D used in the formulation controlled release layer. These results obtained clearly suggest that the sustained release oral delivery system for indapamide could be designed with satisfying drug release profile approved.

  • https://doi.org/10.4333/KPS.2008.38.2.105 인용 PDF KSCI