• Archives of Pharmacal Research
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• 제13권1호
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• pp.64-68
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• 1990

The stabilization effect of .alpha.-tocopherol incorporated into liposomal phospholipid membrane was investigated by fluorospectrophotometry and UV-visible spectretarded by the presence of .alpha.-tocopherol in the bilayer of liposomal phospholipid membrane relative to cholesterol-containing liposomes and pure phospholipid liposomes. .alpha.-tocopherol-containing liposomes prolonged the oxidation of liposomes-embedded heme as those of cholesterol-containing liposomes and pure phospholipid liposomes. Thus .alpha.-tocopherol-containing liposomes may be useful for the carrier systems of nutrients and drugs to phospholipid bilayer and stabilized liposomes.

• Applied Microscopy
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• 제19권2호
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• pp.1-16
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• 1989

To investigate the research of the tumor seeker using liposomes with negatively stained. The fine structure and size in liposomes composed of PC, DSPC, DAPC and SM phospholipid were observed. And the yield of vesicle affected with sonication by mechanical force were determined. The results were as follows. 1. The stain of 2% UA are obtained a good resolution from electron microscopic observation to compare the negatively liposomes with PTA, AM and UA solution. 2. The fine structure of liposomes except DAPC, PC and CH alone samples could be observed from EM experiment of liposomes composed of PC, DSPC, DAPC and SM phospholipid. 3. The results of experiment from 10, 20, 40 and 60 times sonication with 30sec, prepared 0.1mM NTA-SM-liposomes were obtained unilamella vesicles from groups of multilamella vesicles of phospholipid. 4. About 50nm diameter liposomes obtained through membration filtration step to prepare homogenized liposomes.

• 한국응용과학기술학회지
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• 제13권1호
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• pp.11-19
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• 1996

The liposomes have been developed in many drugs and cosmetics fields. The liposomes prepared with main compounds of the intercellular lipids and lecithin. Amphiphile nonionic surfactants used for (PEG) n-sitosterol(n=5), diethanolamine cetylphosphate. The effect of gelation for liposomes have been on swelling reaction which have been mixed phospholipid with polyol-group at the high temperature. There were very good encapsulated properties of the active ingredients whether hydrophilic-group(magnesium ascorbyl phosphate, allantoin, sodium hyaluronate) and hydrophobic-group(vitamin-E acetate, vitamin-A palmitate). Optimum condition of liposomes were passed five times in the microfluidizer(700bar), wetting reaction temperature was at $95{\pm}5^{\circ}C$ for a hours. Particle size distribution of the vesicles should be within range 50-560nm(mean 200nm). The stability of liposomes for the course of time was stabilized for six months at $45^{\circ}C$. Application of the cosmetic was prepared moisturizing cream with liposomes of the phospholipid base.

• 대한화장품학회지
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• 제22권2호
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• pp.99-114
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• 1996

The MLV liposomes have been developed in many drugs and cosmetics fields. The phospholipid base is made from ceramides, cholesterol, cholesteryl ester, lecithin, lanolin ester, and B-sitosterol, and surfactants are made by using (PEG)n-sitosterol(n=5) and K-cetyl phosphate. We made visicles stable by passing samples through Microfludizer and croated multilamellar vesicles to make MLV liposomes similar to the structure of men's skin. In order to make MLV liposomes, we created lipid membrane films which a mixure of phospholipid base and polyol group was reacted above Tc(95$^{\circ}C$) by gelation for 3 hours. As the optimum conditions of Microfluidizer, we figured out 700 bar for the passing pressure of samples, 4$0^{\circ}C$ for its temperature, and 3 times of frequency to pass through samples. Our MLV liposomes is stable on conditions of a low temperature(5$^{\circ}C$) and a high temperature(45$^{\circ}C$), which is not to be split in a large range. We produced our own moisturizing cream which has a good affinity to skin by means of this system.

• 한국식품영양과학회지
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• 제27권3호
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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.

• Preventive Nutrition and Food Science
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• 제8권3호
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• pp.235-238
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• 2003

We investigated the effect of the phase transition temperature (T$_{c}$) of phospholipid in liposomes on the stability of incorporated retinol. Two kinds of phospholipid which have different T$_{c}$, L- $\alpha$ -dimyristoyl phosphatidyl choline (DMPC, T$_{c}$=22$^{\circ}$C) and D,L- $\alpha$ -dipalmitoyl phosphatidyl choline (DPPC, T$_{c}$=42$^{\circ}$), were used to prepare liposomes. Liposome with retinol was prepared as multilamella vesicles (MLVs) by the dehydration/rehydration method. The incorporation efficiency of retinol into liposomes prepared from DMPC and DPPC were 99.89$\pm$0.08% and 99.97$\pm$0.03, respectively. The average size of liposomes from DPPC were greater than that of DMPC. Two kinds of liposomes in phosphate buffer (10 mM, pH 7.0) were stored at 15, 30, and 5$0^{\circ}C$, and stability of incorporated retinol was analyzed. The stability of retinol in DMPC liposome was decreased, whereas the stability in DPPC liposome was increased as temperature increased, although the overall protection effect of liposome on the incorporated retinol was greater in DMPC liposomes than in DPPC liposomes.posomes.

• Preventive Nutrition and Food Science
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• 제5권3호
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• pp.177-178
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• 2000

Chemical and photochemical precesses during food storage an preparation rapidly degrade $\beta$-carotene, the most active form of carotenoids. We investigated the possibility of liposomes as tool to preserve $\beta$-carotene. Liposomes with $\beta$-carotene were prepared as multilamellar vesicles by using soybean phosphatidylcholine, in terms of the ratio of $\beta$-carotene to phospholipid and pH. Incorporated efficiency was 99.7% at 1:0.05 of phospholipid : $\beta$-carotene and at pH 9.0. As the concentration of $\beta$-carotene increased, the incorporated efficiency increased progressively. pH did not affect the incorporation efficiency greatly.

• 약학회지
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• 제38권2호
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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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• 제7권2호
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• pp.120-124
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• 1986

In order to investigate effective solar energy conversion system, the light-induced electron transfer reactions have been examined across single-lamellar liposomes incorporated organic photosensitizers such as anthracene and naphthalene derivatives. We have observed photosensitized reduction of methyl viologen (1,1'-dimethyl-4,4'-$bipyridinium^{2+}$) dissolved in the exterior aqueous phase of the pigmented phospholipid liposomes when EDTA, as electron donor, is dissolved in the enclosed aqueous phase of the liposomes. The anthroyl stearic acid incorporated in the hydrophobic bilayer of liposomes leads to much less quantum yield for the photosensitized reduction of $MV^{2+}$ than the anthracene carboxylate incorporated in the outer hydrophilic layer. However, ${\beta}$-carotene with anthroyl stearic acid incorporated into the bilayer enhances the quantum yield significantly (${\Phi}{\simeq}0.2-0.3$), preventing the reverse reaction of electron transfer ($MV^+_\ {\rightarrow}MV^{2+}$) so that it might be useful for solar energy conversion into chemical energy. A naphthalene derivative, octadecyl naphthylamine sulfonic acid incorporated into the outer layer of liposomes results in less efficiency of $MV^{2+}$ reduction than anthroyl stearic acid. These results have been also tested with respect to lipid components of liposomes.

• Journal of Photoscience
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• 제7권2호
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• pp.63-66
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• 2000

A study of the interaction between lysozyme and phospholipid liposomes is essential for a systematic approach for understanding the action mechanism of lysozyme. So we want to clarify the interactions of lysozyme with phospholipid liposmes. We observed that lysozyme more interacts with negatively charged liposomes than with neutral liposome. More hydroxy groups of the phospholipid was very important on that interactions. We recognized the importance of electrostatic interactions in the process of fusion induced by lysozyme. As indicated by UV/Vis experiments, leakage and fusion are two uncoupled process.