• Title/Summary/Keyword: responsive

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Chemoenzymatic Synthesis of Dual-responsive Amphiphilic Block Copolymers and Drug Release Studies

  • Chen, Peng;Li, Ya-Peng;Wang, Shu-Wei;Meng, Xin-Lei;Zhu, Ming;Wang, Jing-Yuan
    • Bulletin of the Korean Chemical Society
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    • v.34 no.6
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    • pp.1800-1808
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    • 2013

  • Dual-responsive amphiphilic block copolymers were synthesized by combining enzymatic ring-opening polymerization (eROP) of ${\varepsilon}$-caprolactone (CL) and ATRP of N,N-dimethylamino-2-ethyl methacrylate (DMAEMA). The obtained block copolymers were characterized by gel permeation chromatography (GPC), $^1H$ NMR and FTIR-IR. The critical micelle concentration (CMC) of copolymer was determined by fluorescence spectra, it can be found that with hydrophilic block (PDMAEMA) increasing, CMC value of the polymer sample increased accordingly, and the CMC value was 0.012 mg/mL, 0.025 mg/mL and 0.037 mg/mL for $PCL_{50}$-b-$PDMAEMA_{68}$, $PCL_{50}$-b-$PDMAEMA_{89}$, $PCL_{50}$-b-$PDMAEMA_{112}$, $PCL_{50}$-b-$PDMAEMA_{89}$ was chosen as drug carrier to study in vitro release profile of anti-cancer drug (taxol). The temperature and pH dependence of the values of hydrodynamic diameter (Dh) of micelles, and self-assembly of the resulting block copolymers in water were evaluated by dynamic light scattering (DLS). The result showed that with the temperature increasing and pH decreasing, the Dh decreased. Drug-loaded nanoparticles were fabricated using paclitaxel as model. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) had been explored to study the morphology of the hollow micelles and the nanoparticles, revealing well-dispersed spheres with the average diameters both around 80 nm. In vitro release kinetics of paclitaxel from the nanoparticles was also investigated in different conditions (pH and temperature, etc.), revealing that the drug release was triggered by temperature changes upon the lower critical solution temperature (LCST) at pH 7.4, and at $37^{\circ}C$ by an increase of pH.

  • https://doi.org/10.5012/bkcs.2013.34.6.1800 인용 PDF KSCI

The Change of K-MMSE Following Donepezil Medication in Patients with Alzheimer's Disease and Small Vessel Dementia, and the Characteristics of Alzheimer's Disease with Meaningful K-MMSE Change (알쯔하이머병과 소혈관성 치매에서 Donepezil 복용 후 K-MMSE의 변화와 의미 있는 K-MMSE 변화를 보이는 알쯔하이머병 환자의 특징)

  • Kwak, Yong Tae;Han, Il-Woo;Kim, June;Lee, Yu-Sang
    • Korean Journal of Biological Psychiatry
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    • v.12 no.2
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    • pp.98-106
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    • 2005

  • Objectives:Donepezil is a widely used drug for the treatment of patients with Alzheimer's disease(AD). The aim of the present study was to clarify the efficacy and the characteristics of responders to donepezil. Methods:Patients with probable AD(n=80;75.7 years) and small vessel dementia(SVD)(n=18;77.8 years) who received donepezil were retrospectively analyzed using Alzheimer's registry, and three questions were asked:1) Does donepezil therapy improves cognitive symptoms in patients with dementia? 2) If donepezil improves cognitive symptoms, which items of the K-MMSE are improved? 3) What are the characteristics of responder to donepezil medication? Results:1) After donepezil medication, cognitive function measured by the K-MMSE was significantly improved in both types of dementia(AD and SVD), However, statistical differences were not found between these groups. 2) In a clinical trial of donepezil, the patients performed better than before mediation on K-MMSE items assessing orientation, recall, construction, concentration, calculation. 3) In AD, the K-MMSE score before medication was closely related with response of donepezil. Conclusion:This study suggests that donepezil improves various cognitive functions in both types of dementia, and the responsive group had significantly lower K-MMSE scores than the non-responsive group before medication.

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