• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.283-283
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• 1996

The hydrolyzed-lactose milk for the lactase-deficient subject is sweeter than whole milk, and some subjects dislike its taste. To overcome this shortcoming the dried liposomes containing ${\beta}$-galactosidase to digest lactose in milk after drinking were prepared and examined the possible application of this dried liposomes to the lactase-deficient subjects. To improve the stability of conventional liposome suspension, the dried liposomes in the presence of trehalose were prepared by the dehydration-rehydration vesicles method. Small unilamellar vesicles, prepared with egg phosphatidyl cholesterol, and cholesterol, were mixed with ${\beta}$-galactosidase solution and then ;up[jo;ozed. The freeze-dried liposome was rehydrated and centrifuged. The resultant multilamellar vesicles were mixed with trehalose(4g/g lipid) and then lyophilized to produce final dried liposome. Trehalose increased the entrapping efficiency of liposomes by 3 fo1d compared to the liposomes without trehalose (13% vs. 46%).

• 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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2688-2691
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• 2008

This study addresses a microfluidic method to uniformly form diacetylene (DA) liposomes and control their size. DA liposomes are biochemical sensor materials with a unique property such that when they are polymerized to polydiacetylene (PDA) they exhibit non-fluorescent blue to fluorescent red phase transition upon chemical or thermal stress. The liposome size and distribution are important because they significantly affect the phase transition. So far, DA Liposomes, have been prepared by mixing of bulk phases leading to heterogeneous, polydisperse distribution in size. Therefore, additional post-processes are required such as sonication or membrane extrusion to obtain an appropriate size of liposomes. Here, we report a novel strategy using a microfluidic chip and hydrodynamic focusing to form DA liposomes and control their size. Preliminary results obtained by scanning electron microscope (SEM) and dynamic light scattering (DLS) show that the microfluidic strategy generates more monodispersed liposomes than a bulk method.

• KSBB Journal
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• 제15권1호
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• pp.96-99
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• 2000

Octadetkanubc으로 수식된 아미노산을 DPPC 혹은 DSPC와 혼합하여 리포솜-아미노산 결합체를 제조하였다. 리포솜의 크기는 100nm이고 구형이었다. DPPC와 글루탐산을 혼합하여 제조한 리포솜-아미노산 결합체가 글루타민이나 아스파라긴을 사용했을 때보다 포도당과의 친화성이 컸다. 제조한 리포솜의 안정성 면에서도 DPPC와 glucamic acid으로 구성된 리포솜-아미노산 결합체의 안정성이 높았다. 결국 포도당 친화성과 안정성을 갖춘 리포솜은 DPPC 와 글루탐산의 비가 7 : 3 으로 제조된 리포솜이었다.

• Journal of Pharmaceutical Investigation
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• 제39권6호
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• pp.423-429
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• 2009

Liposomes have been used as one of the efficient carriers for drug delivery. In this study, anionic liposomes of which surface was modified by using both electrostaic interaction between anionic liposomes and cationically charged BSA molecules at lower pH than isoelectric point (pI) of BSA and denaturation of the BSA-coated liposomes by thermal treatment. The thermally denatured BSA-coated liposomes (DBAL) had mean particle diameter of 125.2${\pm}$1.7 nm and zeta potential value of -22.4${\pm}$4.5 mV. Loading efficiency of model drug, doxorubicin (DOX), into liposomes was 83.0${\pm}$2.6%. Results of in vitro stability study of DBAL in blood plasma showed that the mean particle diameter of DBAL 400 did not increase in blood plasma and adsorption of plasma protein was much less than plain or anionic liposomes. Intracellular uptake of DBAL 400 evaluated by confocal microscopy observation was higher than that of PEG liposomes.

• 대한화학회지
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• 제47권3호
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• pp.257-264
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• 2003

본 연구에서는 외부온열 온도$(~40^{\circ}C)$에서 항암약물(doxorubicin)이 방출되는 온도민감성 리포좀에 대하여 연구하였다. 온도민감성 리포좀은 외부온열온도에서 하한임계용액온도의 성질을 나타내는 N-isopropylacrylamide (NIP-AAm)와 Acrylamide(AAm)의 합성고분자에 의하여 변형되었다. 변형된 리포좀으로부터 약물(doxorubicin)의 방출은 온도와 시간의 변화에 따라서 형광강도를 측정하여 결정하였다. Poly(NIPAAm-co-AAm) copolymer에 의하여 변형된 리포좀으로부터 약물(doxorubicin)의 방출은 Poly(NIPAAm-co-AAm) copolymer가 온열온도 범위$(~40{\pm}2^{\circ}C)$에서 적절한 전이를 나타내기 때문에 증가하였다. 또한, 리포좀으로부터 약물의 방출은 5분 이내에 완료되었고, 변형된 리포좀의 크기는 120~170 nm 이었다. 본 연구에서는 온도에 의하여 제어 할 수 있는 온도민감성 리포좀을 제조하였다. 이것은 온도 제어에 따른 종양 표적화에 대한 약물전달시스템에서 활용 될 수 있을 것이다.

• 대한의생명과학회지
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• 제10권3호
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• pp.187-194
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• 2004

A short peptide corresponding to the nuclear localization signal (NLS) of human immunodeficiency virus (HIV)-l Tat protein, Arg-Lys-Lys-Arg-Arg-Gln-Arg-Arg-Arg, was employed to improve the efficiency of cellular uptake of nucleic acids. The peptide was first mixed with a reporter plasmid and then with cationic liposomes to form a tripartite complex of DNA/peptide/liposomes (DPL). Transfection efficiency of the DPL complex was compared with that of the conventional DNA/liposomes (DL) complex. When the DPL complex was formed with various cationic liposomes, DOTAP/DOPE (DP) liposome exhibited superior transfection efficiency to other liposomes tested in vitro. With the inclusion of the peptide, the DPL complex showed much enhanced transfection in various cancer cell lines. Particularly, transfection of the DPL complex in serum increased cellular uptake of a transgene up to 2 fold when compared with that in a serum free condition. Further, when the DPL complex was infused through the ureteric route of a rat, transfection efficiency was shown to be better in reporter gene expression than that obtained with the DL complex. This study shows that the DPL complex that is easy to formulate can be employed for much enhanced cellular uptake of a trans gene.

• 대한의생명과학회지
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• 제17권3호
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• pp.211-216
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• 2011

The chitosan-coated liposomes (chitosomes) were designed to improve the stability in the gastrointestinal (GI) tract and to enhance the efficacy for oral drug delivery of liposomes. The phosphatic acid (PA)-incorporated anionic liposomes were surface-coated with water soluble chitosan (WSC) by electro-ionic interaction. The shape of the chitosomes observed by transmission electron microscopy (TEM) was spherical in all the formulations and the coating layer by WSC could be founded through TEM images. The mean size and the zeta potential values of the chitosomes increased significantly with depending on the content of WSC added for coating the liposomes. The stability of the chitosomes in the GI tract was confirmed through the change of relative turbidity of the liposomal suspension. The plain liposomes (plasomes) suspension without adding WSC clearly showed the change of relatively turbidity in simulated gastric fluid (SGF), while the change degree of turbidity of the chitosomes in the SGF decreased as increasing of WSC content added for coating liposome. In the 5-CF release study from the plasomes and chitosomes, the plasomes released >90% of the initial 5-CF content at 4 h of release measurement. In contrast, the chitosomes released below 40% of initial content of 5-CF. In conclusion, these results indicate that the chitosomes can be used as a potential carrier for effective oral drug delivery.

• Journal of Pharmaceutical Investigation
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• 제40권3호
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• pp.187-192
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• 2010

We aimed to evaluate the effect of temperature, pH, and light conditions on the stability of porcine placental extract (PPE)-loaded liposomes with different surface charges. The size distribution profiles and in vitro release patterns were investigated by dynamic light scattering method and spectrophotometry. The stability of PPE-loaded liposomes was affected by the surface charges of the liposomes. As compared to neutral and anionic liposomes, cationic liposome formulations showed significantly lower physical stability. At the test storage conditions of different temperatures and pHs, the mean sizes of cationic PPE-loaded liposomes substantially increased. In contrast, neutral and anionic liposomes did not reveal significant changes in mean sizes upon various storage conditions. The neutral and anionic liposomes showed no significant differences in the release profiles of PPE after storage at various temperatures and pHs. Our results indicate that anionic and neutral liposome compositions might be more suitable for the formulations of PPE providing the higher stability.

• Journal of Pharmaceutical Investigation
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• 제35권1호
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• pp.25-31
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• 2005

Depot system for local drug delivery using chitosan hydrogel has been developed to enhance the therapeutic efficacy and to prevent the severe side effect in whole body. Thus, we have prepared an injectable chitosan hydrogel containing liposomes to treat cancers clinically. Anionic liposomes incorporated to improve sustained release efficiency within chitosan hydrogel. The chitosan solution containing liposomes was designed to form a hydrogel complex at body temperature. The released behavior of doxorubicin from liposomes in chitosan hydrogel showed sustained-release caused by diffusion of doxorubicin from temperature responsive liposome into chitosan hydrogel. The chitosan hydorgel containing liposomes enhanced the therapeutic potency for the solid tumor in vivo system. Our results indicate that the liposomes in chitosan hydrogel represent a depot system for local drug delivery.