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Seoul, South Korea

Li L.,Chungnam National University | Moon H.T.,Mediplex Corporation | Park J.-Y.,National Cancer Center | Heo Y.J.,National Cancer Center | And 5 more authors.
Macromolecular Research

Novel heparin-based self-assembled nanoparticles were developed for photodynamic cancer therapy. A heparin-poly(β-benzyl-L-aspartate) (HP) amphiphilic copolymer was synthesized for effective delivery of a hydrophobic photosensitizer, pheophorbide a (Pheo). The anti-coagulant activity of the HP copolymer decreased significantly, as measured by an anti-FXa chromogenic assay. Pheo was effectively incorporated into the HP nanoparticles using a dialysis technique. A good drug-loading content was obtained by altering the composition of the HP copolymer and Pheo/HP feed ratio. The Pheo-loaded HP nanoparticles had an average diameter of 117-189 nm, a negatively charged surface, and a sustained drug release pattern. These properties may allow them to passively target the tumor site through an enhanced permeability and retention (EPR) effect. Furthermore, the Pheo-loaded HP nanoparticles demonstrated marked photocytotoxicity and minimal darktoxic without a light treatment. The 6HP-Pheo15 nanoparticles were internalized into SCC7 cancer cells and damaged the cells after a light treatment. This suggests that HP nanoparticles have potential as an effective delivery system for clinical PDT. [Figure not available: see fulltext.] © 2011 The Polymer Society of Korea and Springer Netherlands. Source

Kim J.S.,Chungbuk National University | Cho K.J.,Catholic University of Korea | Tran T.H.,Chungnam National University | Nurunnabi M.,Chungbuk National University | And 3 more authors.
Journal of Colloid and Interface Science

Luminescent near-infrared (NIR) CdTe/CdSe QDs were synthesized and encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanospheres to prepare stable and biocompatible QDs-loaded nanospheres for in vivo imaging. QDs were encapsulated with PLGA nanospheres by a solid dispersion method and optimized to have high fluorescence intensity for in vivo imaging detection. The resultant QDs-loaded PLGA nanospheres were characterized by various analytical techniques such as UV-Vis measurement, dynamic light scattering (DLS), fluorescence spectroscopy, and transmission electron microscopy (TEM). Finally, we evaluated toxicity and body distribution of QDs loaded in PLGA nanospheres in vitro and in vivo, respectively. From the results, the QDs loaded in PLGA nanospheres were spherical and showed a diameter range of 135.0-162.3. nm in size. The QD nanospheres increased their stability against photooxidation and photobleaching, which have the high potential for applications in biomedical imaging. We have also attained non-invasive in vivo imaging with light photons, representing an intriguing avenue for obtaining biological information by the use of NIR light. © 2010 Elsevier Inc. Source

Jeon O.-C.,Sungkyunkwan University | Jeon O.-C.,Mediplex Corporation | Hwang S.R.,Seoul National University | Al-Hilal T.A.,Seoul National University | And 5 more authors.
Pharmaceutical Research

Purpose: Since the absorption of ceftriaxone (CTO) in the intestine is restricted by its natural physiological characteristics, we developed a series of small synthetic compounds derived from bile acids to promote the absorption of CTO in the gastrointestinal tract. Methods: Several bile acid derivatives were screened by measuring water solubility and partition coefficient of their complexes with CTO. The pharmacokinetic parameters of the selected CTO/HDCK ionic complex in monkeys were evaluated. The absorption pathway of CTO/HDCK complex was evaluated using Caco-2 cells and MDCK cells transfected with ASBT gene. Results: HDCK enhanced the apparent membrane permeability of CTO 5.8-fold in the parallel artificial membrane permeability assay model. CTO/HDCK complex permeated Caco-2 cell via transcellular pathway, and interaction of the HDCK complex with ASBT was important to enhance uptake. When CTO/HDCK (equivalent to 50 mg/kg of ceftriaxone) formulated with lactose, poloxamer 407 and Labrasol was orally administered to monkeys, its maximum plasma concentration was 19.5 ± 1.8 μg/ml and oral bioavailability 28.5 ± 3.1%. Conclusions: The CTO/HDCK formulation could enhance oral bioavailability of CTO in non-human primates. This oral formulation could be an alternative to injectable CTO with enhanced clinical effects. © 2012 Springer Science+Business Media New York. Source

MEDIPLEX Corporation, Snu R&Db Foundation and St Pharm Co. | Date: 2012-11-29

The present invention relates to a method for preparing an end site-specific macromolecule-bile acid oligomer conjugate, comprising conjugating a bile acid oligomer which is prepared by oligomerization of two or more bile acid monomers to the terminal site of a macromolecule; a method for body absorption of an end site-specific macromolecule-bile acid oligomer conjugate, comprising administering the macromolecule-bile acid oligomer conjugate prepared by the above method to a subject orally; an end site-specific macromolecule-bile acid oligomer conjugate wherein the bile acid oligomer is conjugated to the terminal site of macromolecule; a composition comprising the conjugate; an oral formulation for macromolecule comprising the conjugate, a solubilizer, an excipient, a disintegrant, a binder, and a lubricant; a pharmaceutical composition comprising a heparin-bile acid oligomer conjugate wherein the bile acid oligomer is conjugated to the terminal site of heparin; and a method for treating thrombosis using said composition.

Alam F.,Seoul National University of Science and Technology | Chung S.W.,Seoul National University | Hwang S.R.,Chosun University | Kim J.-Y.,Seoul National University | And 5 more authors.
Journal of Applied Toxicology

In our previous studies, taurocholic acid (TA)-conjugated low-molecular-weight heparin derivative (LHT7) has been proven to be a potent anti-angiogenic agent by demonstrated successful blockage capability of vascular endothelial growth factors (VEGF). Preliminary safety evaluations were conducted based on its mechanism of action and chemical behavior. For this purpose, acute toxicity study, and hematological and serological evaluations were carried out. Additionally, in order to evaluate mechanism-related side effects, both blood pressure and the occurrence of proteinuria were measured using a treatment regime of multiple high doses of LHT7 in a biodistribution study. LD50 values for LHT7 in female and male mice were 56.9 and 64.7 mg kg-1 doses, respectively. There were no vital fluctuations in the serological and hematological parameters, except for the elevated levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) at 100 and 200 mg kg-1 doses of LHT7, representing vital changes in the liver function. Moreover, the results of mechanism-related studies showed that blood pressure at 50 mg kg-1 did not change but showed elevated levels of protein in urine. In the biodistribution study, a slight accumulation of LHT7 in the kidney and the liver were observed at the 50 mg kg-1 repeated dose owing to the presence of bile acid. No fatal damage was observed in this study; most observations were related to the chemical composition or the mechanism of action of the material. © 2014 John Wiley & Sons, Ltd. Source

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