• Title, Summary, Keyword: Poly(l-lactide)

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Studies on Synthesis of Block Copolymers Containing Polyester and Polypeptide for Drug Delivery System Ⅰ. Synthesis and Characterization of Copolymer of L-Lactic Acid and L-Glutamic Acid (폴리펩티드-의약 전달체 및 폴리펩티드 공중합체의 합성 및 물성에 관한 연구 (Ⅰ) L-Lactic Acid 와 L-Glutamic Acid 공중합체의 합성 및 그의 물성)

  • Kim, Hong Beom;Seong, Yong Gil;Jeong, Jae Hui;Baek, Hyeong Ge;Min, Tae Jin;Kim, Yeong Sun
    • Journal of the Korean Chemical Society
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    • v.34 no.2
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    • pp.203-210
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    • 1990
  • As a possible biocompatible and biodegrable polymer skeleton for drug delivery system, block copolymers of L-lactic acid and L-glutamic acid with different composition were synthesized and characterized. Poly (L-lactide) was prepared by polymerization of L-lactide with zine oxide at $130^{\circ}C$ for 72 hrs. 3-Amino-l-propanol was introduced to poly (L-lactide) by an ester linkage in order to initiate polymerization. Polymerization of $\gamma-benzyl-L-glutamate-N-carboxyanhydride(\gamma-BLG-NCA)$ utiliizing the amino group of modified poly (L-lactide) as an initiator gave rise to the block copoly $(L-lactide-\gamma-benzyl-L-glutamate).$ The NMR study of resulting block copolymers showed that the composition of L-lactic acid and $\gamma-benzyl-L-glutamate$ in block copolymers was depended on the weight ratio of poly (L-lactide) and $\gamma-BLG-NCA.$ The thermal properties of the resulting block copolymers were determined by the differential scanning calorimetry and by the thermogravimetry.

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Synthesis and Properties of Triblock and Multiblock Copolymers Consisting of Poly(L-lactide) and Poly(oxyethylene-co-oxypropylene)

  • Lee, Chan-Woo;Kang, Young-Goo;Kun Jun
    • Macromolecular research
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    • v.9 no.2
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    • pp.84-91
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    • 2001
  • Both A-B-A triblock and multiblock copoly(ester-ether)s consisting of poly(L-Lactide) and poly(oxyethylene-co-oxypropylene) were prepared and characterized. The preparation of the triblock copolymer was done by ring-opening copolymerization of L-lactide with a commercially available telechelic copolyether, Pluronic$\^$TM/(PN) by catalysis of stannous octanoate. The molecular weight and unit composition of the produced copolymers were successfully controlled by changing the L-lactide/PN ratio in feed. However, a high molecular weight copolymer incorporating PN in large amount was not obtained because the molecular weight of the resulting copolymer was limited at a high L-lactide/PN composition. The multiblock copolymer was synthesized by the copolycondensation of oligo(L-lactic acid) prepared by thermal dehydration of L-lactic acid, PN, and dodecanedioic acid as carboxyl/hydroxyl adjusting agent. This polycondensation proceeded by catalysis of stannous oxide to give multiblock copolymers with high molecular weight and wide range of compositions.

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Drug-release Properties of Double-layered Microspherical Carriers which Consist of Outer Shell of Poly(D,L-lactide) and Inner Core of Alginate or Chitosan (Poly(D,L-lactide)를 외부 껍질로 하고 Alginate 또는 Chitosan을 내부 코어로 구성한 이중미립구 담체의 약물방출 특성)

  • Kim, Ja Won;Song, Min Jeong;Lee, Sang Min;Lim, So Ryong;Jung, Su Jin;Kim, Hong Sung
    • Polymer Korea
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    • v.36 no.6
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    • pp.699-704
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    • 2012
  • Double-layered polymeric carrier was designed for release control of hydrophilic drug in oral administration. Biopolymeric chitosan and alginate were examined as polar absorbents, poly(D,L-lactide) as a hydrophobic shell, and theophylline and diclofenac sodium as loading drugs. The fabrication of the carriers was prepared in the form of double-layered microsphere for delayed and successively extended release, which consisted of outer shell of poly(D,L-lactide) and inner core of alginate or chitosan with drugs. Morphologies and drug-release behaviors of the carriers were investigated, which were influenced by a combination of polarity between carrier and drug. It was confirmed that the relative polarities of the carriers, the drugs, and the environmental pH affected significantly the drug-release property.

Thermal Decomposition Kinetics of Copolymers Derived from p-dioxanone, L-lactide and Poly(ethylene glycol)

  • Bhattarai Narayan;Khil Myung Seob;Oh Seung Jin;Kim Hak Yong;Kim Kwan Woo
    • Fibers and Polymers
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    • v.5 no.4
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    • pp.289-296
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    • 2004
  • The kinetic parameters, including the activation energy E, the reaction order n, and the pre-exponential factor Z, of the degradation of the copolymers based on the poly(L-lactide) (PLLA) or poly(p-dioxanone-co-L-lactide) (PDO/PLLA) and diol-terminated poly(ethylene glycol) (PEG) segments have been evaluated by the single heating methods of Friedman and Freeman-Carroll. The experimental results showed that copolymers exhibited two degradation steps under nitrogen that can be ascribed to PLLA or PDO/PLLA and PEG segments, respectively. However, copolymers exhibited almost single degradation step in air. Although the values of initial decomposition temperature were scattered, copolymers showed the lower maximum weight loss rate and degradation-activation energy in air than in nitrogen whereas the higher value of temperature at the maximum rate of weight loss was observed in air.

Studies of Degradation Behavior of Stereochemical Poly(lactide) Blend Fibers Prepared by Electrospinning (전기방사에 의한 이성질 폴리락타이드 블렌드의 섬유제조와 분해거동에 관한 연구)

  • Jang, Ei-Sup;Lee, Won-Ki
    • Journal of Environmental Science International
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    • v.23 no.3
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    • pp.473-481
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    • 2014
  • Poly(lactide)s(PLA) is an attractive material to solve the problem of waste plastic accumulation in nature because of its biodegradability. The lactide exists in three stereoisomeric configurations: L-lactide, D-lactide, and meso-lactide. PLA stereocomplexes, formed by the mixing of two enantiomers, poly(L-lactide)(PLLA) and poly(D-lactide)(PDLA), have many favorable characteristics because the stereocomplex showed $50^{\circ}C$ higher melting point than each enantiomeric polymer and the resistance toward degradation increased. In this study, we investigated the influence of the composition and the optical purity of each component on the formation of stereocomplexes. Also, the nanofibers of stereochemical PLA and their blends were prepared by electrospinning method. The properties of the obtained fibers were analyzed by differential scanning calorimetry and scanning electron microscopy. The results showed that a degree of stereocomplex was controlled by change of optical purity of each component. The enzymatic degradation of the fibers were strongly dependent on the stereocomplex.

Synthesis of Segmented and Block Poly(L-lactide-co-p-dioxanone) Copolymers and Comparison of in-vitro Behavior of the Copolymers (Poly(L-lactide-co-p-dioxanone) 세그먼트와 블록 공중합체의 합성 및 in-vitro물성 비교)

  • 김학용;이상욱;이덕래;길명섭
    • Textile Science and Engineering
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    • v.39 no.2
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    • pp.167-172
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    • 2002
  • The segmented and block copolymers of poly(L-lactide-co-p-dioxanone)(PDO) and L-lac-tide were prepared successfully by ring-opening polymerization in the presence of lauryl alcohol with stannous octoate catalyst. The products were characterized by SEM, $^1$H-NMR, $^{13}$ C-NMR, and scanning electron microscopy. The hydrolytic degradation of copolymers was studied in a phosphate buffer solution at pH=7.4 and 37$^{\circ}C$. The degradation behavior was evaluated by analyzing the morphological changes. The weight loss, pH, and inherent viscosity changes suggested diffusion of low molecular weight chain segments into the reaction medium as a consequence of the cleavage of ester bonds On the material. Surface morphological changes observed using SEM suggest a heterogeneous degradation mechanism.

poly(D,L-lactide-co-glycolide) nanoparticles제조와 약물방출 거동 및 생분해도

  • Yu, Jeong-Jun;Jeong, Yeong-Il;O, Dong-Seok;Im, Gyun-Taek
    • 한국생물공학회:학술대회논문집
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    • pp.550-553
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    • 2000
  • The polymeric matrices made with poly(D,L-lactide-co-glycolide) were prepared using copolymer of poly(D,L-lactide) and poly(ethylene glycol) for application of drug delivery systems. Catalyst made use of stannous actoate. Particle size were differ greatly$(435.3{\pm}11.2{\sim}2284.1{\pm}188.5)$ that nanoparticle made use of according to solvent of various kinds. Polymer could a sharp distinction with copolymerized among LE-1, LE-2 and LE-3 of PLA and PEG of content that to examine $^1H-NMR$ of copolymer make refine and reprecipitation. Drug delivery effect at PLGA nanoparticle : PLA amount more then proved highly drug delivery amount that each LE-1, LE-2, LE-3, drug and solvent was 40mg, 20mg and 10mg. Drug delivery effect proved higher 20mg that change(10mg, 20mg, 40mg) at drug feeding amount with LE-2. The first a lot of drug proved delivery. LE-3 most lactide content proved much delivery since biodegradable on PLGA copolymer result from lactide. Also biodegradable rate was highest at LE-3 much of lactide content, because influence at biodegradable effect of lactide by inclusive of soft PEG.

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Preparation of Microcapsules and Their Application (Poly (L-lactide) Microcapsule) (마이크로캡슐의 제조와 그 응용(폴리락티드 마이크로캡슐))

  • 홍기정;박수민
    • Textile Coloration and Finishing
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    • v.10 no.2
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    • pp.29-36
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    • 1998
  • Poly(L-lactide) microcapsules containing hydrophilic penetrate were prepared by interfacial precipitation method through solvent evaporation from w/o/w emulsion. Effect of four determinative process parameters on the particle size distributions, morphologies, and release properties of microcapsules coated with poly(L-lactide) was investigated. Moreover, susceptible functional cotton fabrics treated with the mentioned microcapsules were prepared and laundry test up to 15 times were done to determine fastness properties. As a result, the prepared poly(L-lactide) microcapsules with a more sharp-distributive, rounder, and more permeable membranes could be prepared by means of protective colloid concentration, solution volume and stirring rate.

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Ring-Opening Polymerization of L-lactide with Glycidol as Initiator (Glycidol을 개시제로 이용한 L-lactide 개환중합)

  • Yim, Jin-Heong;Kim, Da Hee;Ko, Young Soo
    • Polymer Korea
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    • v.37 no.5
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    • pp.606-612
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    • 2013
  • Glycidol-poly(lactide) (Gly-PLA) were synthesized via L-lactide ring opening polymerization with glycidol as an initiator and $Al(O-i-Pr)_3$ catalyst. The structure of Gly-PLA was analyzed and successfully confirmed by 1H NMR. The OH group of glycidol in Gly-PLA was absent according to the $^1H$ NMR analysis, indicating that the terminal OH group of glycidol successfully served as an initiator in the L-lactide polymerization. The solution and bulk polymerizations of L-lactide with glycidol were performed to examine the effect of L-lactide/glycidol molar ratio, polymerization temperature and time on the molecular characteristics of Gly-PLA. The conversion and molecular weight increased with an increase in L-lactide/glycidol molar ratio. Gly-PLA showed the bimodal type DSC curve. The low $T_m$ peak of low molecular weight reduced but the high $T_m$ peak of high molecular weight increased as L-lactide/glycidol molar ratio increased.

Assessment of Biodegradability of Polymeric Microspheres in vivo: Poly(DL-lactic acid), poly(L-lactic acid) and poly(DL-lactide-co-glycolid) microspheres

  • Oh, In-Joon;Oh, Jhin-Yee;Lee, Kang-Choon
    • Archives of Pharmacal Research
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    • v.16 no.4
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    • pp.312-317
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    • 1993
  • To confirm a new evaluation tedhnique for biodegradability of biopolymer microsphers in vivo condition, magnetic microsphere sytem was adopted for tracing the microspheres injected and lodged in micr. Microsphers of poly(DL-lactic acid), poly(L-alctic acid) and poly(DL-lactide-coglycolide)(PLGA) were prepared by solvent-extraction method and their organ distribution and biodegradation in mice was examined. Magnetic microspheres lodged in mice organs were recollected from the homogenates of mice organs with a constant flow magnetic separation apparatus. Recollected microspheres were observed by scanning electron microscopy and also were assayed for their magnetite ocntent by atomic absorption spectrophotometry to evaluate the biodegradability of polymeric microspheres. This method seems to be practical and simple to estimate the biodegradability of biopolymers over the conventional methods.

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