• Title/Summary/Keyword: drug release

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키토산-셀룰로오스 마이크로스피어로부터 5-플루오르우라실의 방출 특성

  • Gu, Chang-Gyu;Ryu, Hwa-Won
    • 한국생물공학회:학술대회논문집
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    • 2000.11a
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    • pp.759-760
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    • 2000
  • 5-fluorouracil loaded chitosan-cellulose microspheres was prepared by W/O/W multiple emulsions solvent evaporation technique which is appropriate to oral drug delivery. The influences of process parameters on the physical characteristics of microspheres and on in vitro drug release were investigated.

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Temperature-Dependent Release of Drug from Copolymers of N-Isopropylacrylamide Containing Liposome (리포솜이 함유된 N-이소프로필아크릴아마이드의 공중합체로부터 온도에 따른 약물의 방출)

  • 박영심;한희동;홍성욱;김승수;신병철
    • Polymer(Korea)
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    • v.28 no.1
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    • pp.59-66
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    • 2004
  • Thermosensitive poly(N-isopropylacrylamide) gels containing temperature-sensitive liposomes showing temperature-dependent sol-gel transition were prepared. The surface of temperature-sensitive liposome was modified with copolymers of N-isopropylacrylamide and octadecylacrylate, which exhibited a lower critical solution temperature at around 30 $^{\circ}C$ After mixing the modified temperature-sensitive liposomes with poly(N-isopropylacrylamide) solution, the temperature-sensitive 1iposomes formed physically cross-linked gels through heating the solution above their lower critical solution temperatures. The release of drug from temperature-sensitive liposomes was determined by measuring fluorescence intensity. The drug release from temperature-sensitive liposomes in poly(N-isopropylacrylamide) gel gradually showed sustained-release with increasing temperature.

Particle Size Distribution, Drug Loading Capacity and Release Profiles of Solid Lipid Nanoparticles of Phenylpropionic Acids (페닐프로피온산계 해열진통제 고형지질나노입자의 입도분포와 약물봉입 및 용출특성)

  • Kim, Yoon-Sun;Kim, Kil-Soo
    • Journal of Pharmaceutical Investigation
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    • v.28 no.4
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    • pp.249-255
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    • 1998
  • Solid Lipid Nanoparticle(SLN), one of the colloidal carrier systems, has many advantages such as good biocompatibility, low toxicity and stability. In this paper, the effects of drug lipophilicity and surfactant on the drug loading capacity, particle size and drug release profile were examined. SLNs were prepared by homogenization of melted lipid dispersed in an aqueous surfactant solution. Ketoprofen, ibuprofen and pranoprofen were used as model drugs and tweens and poloxamers were tested for the effect of surfactant. Mean particle size of prepared SLNs was ranged from 100 to 150nm. The drug loading capacity was improved with the most lipophilic drug and low concentration of surfactant. Particle size and polydispersity of SLNs were changed according to the used lipid and surfactant. The rates of drug release were controlled by the loading drug and surfactant concentration. SLN system with effective drug loading efficiency and proper particle size for the intravenous or oral formulation can be prepared by selecting optimum drug and surfactant.

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Preparation and Characterization of Nanoparticles Using Poly(N-isopropylacrylamide)-$Poly({\varepsilon}-caprolactone)$ and Poly(ethylene glycol)-$Poly({\varepsilon}-caprolactone)$ Block Copolymers with Thermosensitive Function

  • Choi, Chang-Yong;Jang, Mi-Kyeong;Nah, Jae-Woon
    • Macromolecular Research
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    • v.15 no.7
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    • pp.623-632
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    • 2007
  • Thermosensitive nanoparticles were prepared via the self-assembly of two different $poly({\varepsilon}-caprolactone)$-based block copolymers of poly(N-isopropylacrylamide)-b-$poly({\varepsilon}-caprolactone)$ (PNPCL) and poly(ethylene glycol)-b-$poly({\varepsilon}-caprolactone)$ (PEGCL). The self-aggregation and thermosensitive behaviors of the mixed nanoparticles were investigated using $^1H-NMR$, turbidimetry, differential scanning microcalorimetry (micro-DSC), dynamic light scattering (DLS), and fluorescence spectroscopy. The copolymer mixtures (mixed nanoparticles, M1-M5, with different PNPCL content) formed nano-sized self-aggregates in an aqueous environment via the intra- and/or intermolecular association of hydrophobic PCL chains. The microscopic investigation of the mixed nanoparticles showed that the critical aggregation concentration (cac), the partition equilibrium constants $(K_v)$ of pyrene, and the aggregation number of PCL chains per one hydrophobic microdomain varied in accordance with the compositions of the mixed nanoparticles. Furthermore, the PNPCL harboring mixed nanoparticles evidenced phase transition behavior, originated by coil to the globule transition of PNiPAAm block upon heating, thereby resulting in the turbidity change, endothermic heat exchange, and particle size reduction upon heating. The drug release tests showed that the formation of the thermosensitive hydrogel layer enhanced the sustained drug release patterns by functioning as an additional diffusion barrier.

Development of Automated Diffusion Cell for Determining In Vitro Drug Release from Transdermal Device (경피흡수제형의 in vitro 약물방출실험을 위한 연속확산 장치의 개발)

  • Byun, Young-Rho;Choi, Young-Kweon;Jeong, Seo-Young;Kim, Young-Ha
    • YAKHAK HOEJI
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    • v.34 no.3
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    • pp.161-165
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    • 1990
  • An automated, simple, and reliable method was developed for determining in vitro drug release rate from transdermal delivery dosage forms. The patch is held in position in the heating block by sandwiching it between the middle plate and the bottom plate of diffusion cell. The dissolution profile of the commercially available transdermal scopolamine patch was determined over a 72-h period, and the results were compared with those obtained with other methods; paddle-over-disk method, reciprocating method, and diffusion cell method. It was demonstrated that the flow-through method is equivalent in terms of release rate profile and accumulated released drug amount over the lifetime of the dosage form tested. Also this method is simple, reliable and reproducible. Therefore, this technique can be used in a quality control for assuring product uniformity.

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Preparation of Cefaclor-Containing Gelatin Microcapsules and Their Drug Release Characteristics (수용성 약물인 세파클러를 함유하는 젤라틴 마이크로캅셀의 제조 및 약물 방출특성)

  • Cho, Seong-Wan;Park, Jong-Hwa;Park, Jun-Sang;Jang, Joung-Soo;Choi, Young-Wook
    • YAKHAK HOEJI
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    • v.41 no.1
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    • pp.30-37
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    • 1997
  • In order to formulate a controlled release system for oral drug delivery, the microcapsules were prepared in w/o emulsion containing cefaclor as a water-soluble model drug by th e method of interfacial polycondensation. Gelatin wis selected as a suitable polymer for interfacial polycondensation. Gelatin solution containing drug was emulsified in an organic phase under mechanical stirring. After emulsification, terephthaloyl chloride was added as cross linking agent, followed by mechanical stirring, washing and drying. Physical characteristics of microcapsules were investigated by optical microscopy, scanning electron microscopy and particle size analysis. Mean particle sizes of gelatin microcapsules were, in the range, of about 20~50 ${\mu}$m. The microcapsules were in good apperance with spherical shapes before washing, but were destroyed partially after washing and drying, even though some microcapsules were still maintained in their shapes. Contents of cefaclor in the microcapsules were calculated by UV spectrophotometry after 3 days extraction with pH 4 carbonate buffer solution. The effects of cross linking time. pH. concentration of cross-linking agent, and temperature on drug release kinetics have been discussed extensively.

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Drug Release Control of Poloxamer-Poly(acrylic acid) Interpenetrating Polymer Networks (폴록사머-폴리아크릴산 IPNs의 약물 조절 방출)

  • Byun, Eun-Jung;Park, Joo-Ae;Lee, Seung-Jin;Kim, Kil-Soo
    • YAKHAK HOEJI
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    • v.41 no.1
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    • pp.22-29
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    • 1997
  • Poloxamer-poly (acrylic acid) (PAA) interpenetrating polymer networks (IPNs) were prepared via matrix polymerization of acrylic acid with poloxamer prepolymer. The equilibrium s welling of poloxamer/PAA IPNs was determined in various pH medium. The swelling of poloxamer/PAA IPNs was more affected by pH difference compared with the swelling of homo PAA gel due to protonation and deprotonation of the PAA network, followed by reversible formation and dissociation of the interpolymer complex due to hydrogen bonding between acidic hydrogens and ether oxygens. Nonionic/anionic/cationic drugs were incorporated into IPN matriceds as a model drug and their release behavior was studied. Nonionic, drug revealed release patterns depending solely on pH dependent swelling kinetics. In contrast, the release of ionic drugs was significantly affected by ionic drug-polymer interaction as well as the swelling kinetics.

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Preparation and Reconstitution of Core-shell Type Nanoparticles of Poly(ε -caprolactone)/Poly(ethyleneglycol)/Poly(ε -caprolactone) Triblock Copolymers

  • Jeong, Young-Il;Ryu, Jae-Gon;Kim, Young-Hoon;Kim, Sung-Ho
    • Bulletin of the Korean Chemical Society
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    • v.23 no.6
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    • pp.872-879
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    • 2002
  • One of the improtant characteristics of core-shell type nanoparticles is the long-term storage and reuse as an aqueous injection solution when required. For this reason, reconstruction of lyophilized core-shell type nanoparticles is considered to be essential . BAB type triblock copolymers differ from AB type diblock copolymers, which contain the A block as a hydrophilic part and the B block as a hydrophobic part. by not being easily redistributed into phosphate-buffered saline (PBS, pH 7.4, 0.1 M). Therefore, lyophilized core-shell type nanoparticles of CEC triblock copolymer were reconstituted using a somication process with a bar-type sonicator in combination with a freezing-thawing process. Soncation for 30s only resuspended CEC nanoparticles in PBS; their particle size distribution showed a monomodal pattern with narrow size distribution. The bimodal size distribution pattern and the aggregates were reduced by further sonication for 120 s but these nanoparticles showed a wide size distribution. The initial burst of drug release was increased by reconstitution process. The reconstitution of CEC core-shell type nanoparticles by freezing-thawing resulted in trimodal distribution pattern and formed aggregates, although freezing-thawing process was easier than sonication . Drug release form CEC nanoparticles prepared by freezing-thawing was slower than from the original dialysis solution. Although core-shell typenanoparticles of CEC triblock copolymers were not easily performed. Cytotoxicity testing of core-shell type nanoparticles of CEC-2 triblock copolymers containing clonazepam (CNZ) was performed using L929 cells. Cytotoxicity of CNZ was decreased by incorporation into nanoparticles.