• Journal of the Society of Cosmetic Scientists of Korea
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• v.17 no.1
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• pp.64-80
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• 1991

The SKINTEX Method is based on a two-compartment physico-chemical model which includes a Biomembrane Barrier in compartment one and an organized macromolecular matrix in compartment two. Test samples absorb onto or permeate through the keratin/collagen Biomembrane Barrier and then can interact with the organized macromolecular matrix. Changes in the integrity of the barrier release a dye indicator: Changes in the matrix can alter its transparency. The sum of these two responses is read spectrophotometrically at 470nm. An early investigation of 950 chemicals and formulations in the SKINTEX System produced results which were 89% concordance to in vivo Draize dermal irritation results obtained with 24-hour occluded application of test samples with-out abrasion and standard scoring. Alkaline materials were analyzed in a specialized SKINTEX AMA Protocol. In this early study, the model did not distinguish nonirritant test materials and formulation with PDII(Primary Dermal Irritation Index)in the range from 0 to 1.2, A High Sensitivity Assay Protocol(HSA)was developed to amplify the changes in both compartments of this model and provide more accurate calibration of these changes. A study of 60 low irritation test samples including cosmetics, household products, chemicals and petro-chemicals distinguished nonirritants with PDII $\leq$ 0.7 for 26 of 30 nonirritants. A second protocol was developed to evaluate the SKINTEX model predictability with respect to human irritation. The Human Response Assay (HRA )has been optimized based on differences in penetration and irritation responses in humans and rabbits. An additional 32 test materials with different mechanisms and degrees of dermal toxicity were evaluated by the HRA. These in vitro results were 86% concordant to human patch test results. In order to further evaluate this model, a Standard Chemical Labelling (SCL) Protocol was developed to optimize this system to predict Draize dermal irritation results after a 4-hour application of the test material. In a study of 52 chemicals including acids, bases, solvents, salts, surfactants and preservatives, the SCL results demonstrated 85% concordance to Draize results for a 4-hour application of test samples on non-abraded rabbit skin. The SKINTEX System, including three specialized protocols, provided results which demonstrated good correlation to the endpoint of dermal irritation in man and rabbits at different application times.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.426-432
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• 2012

The activity of an antimicrobial peptide, protegrin-1 (PG-1), on lipid membranes was investigated using solidstate NMR and a new sampling method that employed mechanically aligned bilayers between thin glass plates. At 95% hydration and full hydration, the peptide respectively disrupted 25% and 86% of the aligned 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphotidylcholine (POPC) bilayers at a P/L (peptide-to-lipid) ratio of 1/20 under the new experimental conditions. The kinetics of the POPC bilayers disruption appeared to be diffusioncontrolled. The presence of cholesterol at 95% hydration and full hydration reduced the peptide disruption of the aligned POPC bilayers to less than 10% and 35%, respectively. A comparison of the equilibrium states of heterogeneously and homogeneously mixed peptides and lipids demonstrated the importance of peptide binding to the biomembrane for whole membrane disruption.

• Textile Coloration and Finishing
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• v.3 no.2
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• pp.43-48
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• 1991

Cellulose acetate (CA) and poly-4-vinyl pyridine (PVP) in various weight proportions were mixed in a mixed solvent of trifluoroacetic acid: methylene chloride/6:4 (v:v). CA was miscible with PVP in that solvent system. CA/PVP/solvent show liquid crystal in a certain range of concentration and the nature of that liquid crystal was cholesteric. Films of the liquid crystal composite cast from the liquid crystal solutions of CA/PVP were tested in a viewpoint of biomembrane. Results show that considering permselectivity CA/PVP membrane is better than that of CA and CA/PVP membrane is closer to cell membrane.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.3
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• pp.508-517
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• 1998

We investigated the effects of godulbaegi extracts on the physiochemical properties of biological membranes as membrane stability and fluidity employing the phospholipid liposomal membrances as a biomembrane-mimetic system. The addition of the godulbaegi extracts to the phospholipid exterted great effects stagbilized the barrier function of the liposomal membranes in proportion to the concentration of the additive and significantly increased the membranes fluidity. The values of the fluorescence polarization of 1,6-diphenyl 1,3,5-hexatriene (DPH) decreased gradually as the temperature increased, and decreased abruptly near the phase transition temperature (Tm) of the liposome from gel to liquid crystalline state as usual. These results suggest that the activities of the godulbaegi extracts to enhance the stability and fluidity of the liposomal membranes have implication in their biological activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.3
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• pp.518-524
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• 1998

Liposomes have been widely employed as biomembrane-mimetic system and drug-delivery system. In these applications, the low stability of liposomes has been the most serious problem. They have relatively short half-lives and easily lysed through interactions with biological components. This study was performed to investigate the effects of godulbaegi extracts on the fludity of phospholipid liposomes. We used dipalmitoyl phosphatidylcholine(DPPC) liposomes which make most stable liposomes among the other phosphatidylcholines. The thermograms of the DPPC liposomal bilayers incorporated with the hexane extract of godulbaegi(Ixeris sonchifolia H.) were obtained, and the enthalpy changes and the sizes of cooperative unit of the transition were calculated. The incorporation of the Ixeris sonchifolia H. into the liposomal bilayers effectively reduced the transition temperature at which the transition from gel state to liquid-crystalline state occurs, broadened the thermogram peaks, and reduced the ratio of van't Hoff to calorimetric enthalpies. These results indicate indicate that the godulbaegi extracts (Ixeris sonchifolia H.) have significant effects on the fluidity of biological membrance.

• Textile Coloration and Finishing
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• v.7 no.2
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• pp.63-69
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• 1995

To improve the blood compatibility of chitosan membranes, 2-(methacryloyloxy)-ethyl-2-(trimethylammonium)ethyl phosphate(MTP), which is a methacrylate with phospholipid polar groups, was grafted on the surface of chitosan membranes and the biocompatibility of MTP-grafted chitosan membranes was investigated. The permeation coefficient gradually decreased with increasing in molecular weights of biocomponents below 10$^{4}$, and drastically decreased above 10$^{4}$. This result corresponds with the permeability of solutes in case of hemodialysis membranes. The MTP-grafted chitosan membranes displayed less blood cell adhesion than the chitosan membranes. This may due to the formation of biomembrane4ike surface by adsorption and arrangement of phospholipid molecules from serum onto the MTP copolymer surface.

• Archives of Pharmacal Research
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• v.13 no.2
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• pp.192-197
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• 1990

The microviscosites of the lipid bilayers of liposomal membranes of phospholipids were measured by the intermolecular excimer, formation method employing pyrene as a fluorescence probe, and the effects of n-alkanols and other local anesthetics on the microviscosity were investigated. The results showed that the n-alkanols and the ohter local anesthetics effectively lowered the microviscosity of the lipid bilayer of the dipalmitoyl phosphatidycholine liposomal membrane in proportion to the concentration of the additives. Moreover, there was a fairly good correlation between the ocal anesthetic activities and the microviscosity-lowering activities of these drugs. This results suggests that the nerve blocking activity of local anesthetics might have some relation with their activity fluidizing the lipid bilayer of biomembrane.

• Journal of Integrative Natural Science
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• v.1 no.2
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• pp.76-78
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• 2008

A series of the long-chain iron(II) alkylsulfonate hydrates were synthesized via self-assembly of surfactant alkyl chains in aqueous medium. Reaction of iron(II) salts with n-alkylsulfonate yields lamellar $Fe(CnH2n+1SO3)2{\cdot}4H_2O$. These compounds show a layered structure, as determined by XRD, consisting of alternating organic alkylsulfonate layers and inorganic iron(II) hydrate layers, with interlayer distances of upto 3.2 nm. This lamellar structure may be attributed to the amphiphilic nature of the surfactants, mediating the coordination and H-bionding interactions, and the hydrophobic alkyl chains. An alkyl chain packing of present system are differ from those of similar Cu(II) series, which are attributed from the size of hydrated metal(II) ions.

• Archives of Pharmacal Research
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• v.17 no.3
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• pp.182-189
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• 1994

The effect of lipophilicity on the mechanisms of drug absorption through biomembranes was investigated empolying HPLC system and the fluorescence technique. Human erythrocyte ghost membranes were used as a model biomembrane. A series of four parabens (methyl, ethyl, rpopyl, and butyl) and p-hydroxybenzoic acid were used as the model drugs for lipophilicities and their partition coefficients were measured in Sorensen's phosphate buffer solution (pH 5)/octanol system. Absorption amount of parabens through erythrocyte ghost membranes increased with an increase of lipophilicity resulted from the addition of methylene group to the n-alkyl chain of parabens. And the effect of parabens on the fluidity of ghost membrane also increased with an increase of their lipophilicities.

• Preventive Nutrition and Food Science
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• v.4 no.1
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• pp.43-46
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• 1999

Taurine is known to suppress oxidant-induced tissue injury by stabilizing biomembrane and scavanging free radicals. The purpose of this study was to determne the antioxidative and antimutabenic acitvities of taurine, ad to compare those acitivities with major antioxidants. For the measurement of antioxidative capacity, 0.05 , 0.1,0.5 and 1.0mg/ml of taurine, L-Ascorbic acid, alpha-tocopherol, and BHT (dibuty hydroxiy toluene)were prepared and tested for their ability to donate electrons to DPPH (1,1-diphenyl-2-picryl-hydrazyl). Antimutagenic acitivity was examined using the Ames salmonela test system at concentrations of 600, 900 and 1200ug/ml. Results indicated that taurine possesses electron-donating capacity, however, the degree of donation was very weak compared to the major antioxidants tested. However, taurine was evaluated as a potent mutation suppressor. Antimutagenic capacity was in increasing order BHT>taurine>L-ascorbic acid>alpha-tocopherol at concentrations of 600 and 900ug/ml. There was a dose-dependent increase in antimutabenicity of these compounds , however, antimutagenity of the 900ug taurie/plate was not significantly differently from that of 1200ug taurine/plate. These results indicate that taurine effectively suppresses the mutagenicity of AFB1 without noticeable elelctron donating ability.