• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.132-137
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• 2013

The liquid crystal form with phosphatidylcholine contents containing in the hydrogenated lecithin was confirmed. Composition ingredients of the liquid crystal vesicle were phospholipid, ethanol and water and the rosmarinic acid was encapsulated as index material. The mean particle size of the liquid crystal vesicle appeared to form various particles form 480 nm to $3{\mu}m$ depending upon the lipid composition and ultrasonic handling time. The liquid crystal vesicle compared with the liposome showed a very high encapsulation efficiency. The quantity of liquid crystal vesicle increased with respect to the increased quantity of lipid contents in the hydrogenated lecithin. The result from release experiments of the liquid crystal vesicle containing rosmarinic acid showed that the liquid crystal vesicle releases much less than that of liposome.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.201-205
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• 2004

In these several years, as many people have been attracted by the functional cosmetics, there are a lot of study to enhance the stability of active ingredients for light, heat, oxygen, etc. in the academic and industrial field. Especially, catechin is well known as strong anti-oxidant, anti-inflammatory and reducing agent for oxidative stress but it is very unstable for light, heat, oxygen. etc. In this study, the stability and skin penetration of catechin are improved by 3-dimensional method. As I-dimension, porous silica is prepared using sol-gel method, and then catechin is adsorbed in pores of silica. As 2-dimension, solid lipid nanoparticles (SLN) are obtained using non-phospholipid vesicles. Finally 3-dimension is completion through lamellar phase self-organization that combines SLN catechin with skin lipid matrix. We used laser light scattering system, cyro-SEM, chromameter, HPLC and image analyzer to analyze our 3-dimentional systems. According to chromameter date, the color stability of 3-dimensional catechin is enhanced by 5-10 times compared with general liposome systems. We also confirmed through HPLC analysis that 3-dimensional catechin is more long lasting. The effect of skin penetration and wrinkle reduction are improved, too.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.506-510
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• 2002

The effect of antioxidant activity of Platycodon grandiflorum (PG) on the liposomal phospholipid membrane was investigated by spectrophotometry. Membrane oxidation causes damage to the membrane fluidity and permeability. It brings further destruction to the sustenance of biological homeostasis. In addition, it is related to several diseases, aging and carcinogenesis. The sample PG was extracted and fractionated to five different types; butanol (PGMB), ethylacetate (PGMEA), ethylether (PGMEE), hexane (PGMH) and methanol (PGMM). The oxidation indices of PGMEA and PGMEE fractions in oxidized dilinoleoylphosphatidylcholine (DLPC) liposomes had stronger antioxidant activities than that of ${\alpha}$-tocopherol and were similar to antioxidant activities compared with butylated hydroxy toluene (BHT), a well-known potent antioxidant, in oxidized DLPC liposomes. The oxidation indices of PGMM extract, PGMB and PGMH fractions exhibited weak antioxidant activity compared with ${\alpha}$-tocopherol in oxidized DLPC liposomes. The oxidation indiex of PGMEE fractions added with vitamin C showed even strong antioxidant activity in the oxidized DLPC liposomes. The oxidation activity of BHT with vitamin C also proved to be stronger than BHT without vitamin C. Therefore vitamin C evidently helps to improve the effect of antioxidant in DLPC liposomes. These results indicate that potentially bioactive substances in PGMEE fraction has a function as potent antioxidant against phospholipid membrane oxidation.

• YAKHAK HOEJI
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• v.38 no.6
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• pp.637-645
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• 1994

The effect of various drugs on the stability of the liposomal membrane of phosphatidylcholine and cholesterol was studied, employing the fluorescence self-quenching method. Calcein was entrapped into the phospholipid small unilamellar vesicles and the leakage of the fluorescence probe was monitored on adding the drug to the system. The results of the experiments showed that phenothiazine derivatives, some potent local anesthetics and surface active agents were very effective in inducing the leakage of calcein from the liposome. The leakage-inducing activity of these drug substances has been ascribed to their surface activity and the perturbation of the liposomal membrane by these substances. On the other hand drug substance with low surface activity or without amphiphilic moieties did not show any effect or only small effect on the leakage of calcein from the liposomes. The effect of lipid concentration on the stability of the liposomes was also investigated to show that the higher concentrations of lipid more drug was required to induce the leakage. The effect of surface charges of vesicles was also studied, and the results showed that the charge on the liposomes enhanced the stability of the liposomes against the leakage-inducing activity of these drug substances.

• YAKHAK HOEJI
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• v.38 no.2
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• pp.131-139
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• 1994

Calcein-encapsulated small unilamellar vesicles of various lipid composition were prepared using the sonication technique, and their stabilities at $20^{\circ}C$ were examined by measuring calcein leakage from the liposomes. The fluidity of these liposomal bilayers was also investigated by measuring the fluorescence polarization of DPH labelled into the liposomes. The results showed that liposomes made of PC mixtures with different acyl chain length were very stable, which may be due to the formation of interdigitated bilayer structure. The addition of cholesterol further stabilized these PC liposomes. However, addition of cholesterol reduced the encapsulation efficiences of liposomes. The fluidity of the liposomes was significantly decreased by cholesterol in the liquid crystalline state, but not changed in the gel state. These results suggest that the enhanced stability of PC mixture liposomes may be ascribed to the formation of stable interdigitated bilayer structure. In membrane-mimetic and drug-delivery studies, vesicles made of mixtures of various phospholipids are recommended instead of addition of cholesterol to the phospholipid.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.931-935
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• 2013

Lipid events in liposome-mediated transfection (lipofection) are largely unknown. Here we studied whether phospholipase D (PLD), an important enzyme responsible for phospholipid breakdown, was affected during lipofection of HepG2 cells with a luciferase plasmid. Synthetic cholesterol (Chol) derivatives, including $3{\beta}$[L-ornithinamide-carbamoyl]Chol, [polyamidoamine-carbamoyl]Chol and $3{\beta}$[N-(N',N'-dimethylaminoethane)-carbamoyl]Chol, and a cationic lipid, N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride were mixed with a helper lipid dioleoylphosphatidylethanolamine to form respective cationic liposomes. All cationic liposomes were found to stimulate PLD. Although orders of magnitude effects of the cationic liposomes on PLD stimulation did not consistently match those on cytotoxicity and luciferase expression, a causal relationship between PLD activation and cytotoxic effect was remarkable. PLD stimulation by the cationic liposomes was likely due to their amphiphilic characters, leading to membrane perturbation, as supported by similar results obtained with other membrane-perturbing chemicals such as oleate, melittin, and digitonin. Our results suggest that lipofection induces cellular lipid changes such as a PLD-driven phospholipid turnover.

• Journal of Pharmaceutical Investigation
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• v.41 no.1
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• pp.19-24
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• 2011

In order to enhance the clinical efficacy of 5-aminolevulinic acid-induced photodynamic therapy (ALA-PDT), liposomal formulations using bulk hydrogenated phospholipids from soybean were introduced. Three types of lipids, S75-3, S100-3, and SL80-3 were used for formulating ALA. The pH of all the liposomal ALA is 4.5~5.5 and the size is 50~200 nm. All the liposomal formulations gave better ex vivo ALA skin penetration using nude mice skin in Franz cell than free ALA did. Among them, SL80-3 including 22% of lyso-phosphocholine achieved excellent ALA penetration when compared with those of S75-3 and S100-3 which have only 1~2% of lyso-phospholipids. S100-3 showed a little better results than S75-3 did. Addition of humectants (glycerine, propylene glycol, butylene glycol, betaine) in liposomal ALA formulated with SL80-3 produced little enhancing effect in ALA penetration. On the other hand, addition of surfactants (Tween 20, 60, Brij 72, 76, 78) in same liposomal system produced significant increase in ALA penetration. Among them, transferosomal system of lyso-phospholipid, SL80-3 and the surfactant, Brij76 showed the highest ALA penetration. Furthermore, this system also established the highest in vivo PpIX biosynthesis in hairy mice skin of C57BL/6. These results concluded that the transferosome of SL80-3 and Brij76 produced the best results in both ALA penetration and PpIX biosynthesis, and proved good correlation between them.

• KSBB Journal
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• v.6 no.3
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• pp.281-288
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• 1991

This research was carried to investigate the effects of several organic solvents on the enzymatic transphosphatidylation in emulsion and two-phase solvent systems. The solvents having a similar dielectric constant with diethylether were effective for the enzyme activity. Diethylether and butylacetate were the most effective solvents, when added 12-15%(v/v) and 10-40%(v/v), respectively, for the synthesis of phosphatidylglycerol, phosphatidylethyleneglycol and phosphatidylpropyleneglycol. In the emulsion system, the size of ovolecithin liposome was increased and the clearness of the phospholipid bilayer was reduced as increasing the diethylether concentration. In the twophase solvent system, the rapidest reaction was obtained when water-organic solvent ratio was close to 1. The ratio of aqueous phase. however, should be lowered to 37% to gain the sole product of transphosphatidy1ation, without phosphatidohydrolysis.

• BMB Reports
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• v.28 no.2
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• pp.184-190
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• 1995

Functional study of the gap junction channel has been hindered by its inaccessibility in situ. Identification of forms of this channel in artificial membrane has been elusive because of the lack of identifying channel physiology. Connexin32 forms gap junction channels between neighboring cells in rat liver. Connexin32 was affinity-purified using a monoclonal antibody and reconstituted into artificial phospholipid vesicles. The reconstituted connexin32 formed channels through the vesicle membrane that were permeable to sucrose (Stokes radius: $5{\AA}$). The permeability to sucrose was reversibly reduced by acidic pH. In addition, the pH effect on the permeability to sucrose fit well with by the Hill's equation (where, n=2.7 and pK=6.7).

• Journal of Pharmaceutical Investigation
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• v.31 no.3
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• pp.197-200
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• 2001

Lectin-conjugated ellagitannin (LET), a newly introduced melanoma-specific antitumor agent which has been synthesized by conjugation of wheat germ agglutinin as a lectin with praecoxin A as an ellagitannin, was encapsulated into sterically stabilized liposomes (SSL). Modified Folin phenol method was established for the quantitation of LET contents in liposomal formulations protein employing the standard calibration curve with bovine serum albumin. After removal of phospholipid by organic solvent extraction, which interferes the specific selectivity of the Folin-Ciocalteu reagent with the protein, recovery of LET was $94.5{\pm}2.3%$ and the encapsulation efficiency was revealed as $37.8{\pm}5.9%$ for 2.5 mg/ml LET solution.