• Journal of Pharmaceutical Investigation
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• 제31권2호
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• pp.113-117
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• 2001

CKD602, a camptothecin derivative, is a synthetic and water-soluble anticancer agent possessing of topoisomerase I inhibiting activity. DPPC and DSPE-PEG liposomal formulations entrapped with CKD602 were developed. DSPE-PEG liposome, or PEGylated liposome, encapsulating CKD602 composed of dipalmitoylphosphatidylcholine (DPPC), cholesterol and distearoyl-N-monoethoxy poly (ethyleneglycol) succinylphosphatidylethanolamine $(DSPE-PEG_{2000})$ (22:11:2) was prepared by reverse-phase evaporation method. Formed liposomes were characterized in terms of the morphology, size and encapsulation efficiency. To elucidate the in vitro stability, PEGylated liposome was incubated in human plasma, and the adsorbed proteins onto the surface of liposomes were applied to the SDS-PAGE. In vitro cytotoxicity of CKD602 encapsulated in PEGylated liposome was studied in human cervical cancer cell line (HeLa). CKD602 in PEGylated liposome was found to be 40-fold more effective $(IC_{50}=1\;nM)$ than free CKD602 $(IC_{50}=40\;nM)$ in inhibiting the growth of HeLa cells in vitro.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.755-758
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• 2000

포도당 결합성 효소의 결합 부위에 관여하는 아미노산중 하나인 asparagine을 이용하여 리포솜 표면에 결합시켜 포도당 민감성 리포솜-아미노산 결합체를 제조하였다. Asparagine이 결합된 리포솜이 그렇지 않은 리포솜이나 증류수에 비해 포도당 결합정도가 컸다. DPPC에 대한 콜레스테롤 함량이 증가할수록 리포솜의 안정성도 증가하였고, zeta sizer로 입도를 측정한 결과 그 분포를 관찰할 수 있었다.

• Archives of Pharmacal Research
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• 제13권3호
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• pp.246-251
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• 1990

Intermolecular interaction between barbiturates and membrane components such as phospholipid and cholesterol were investigated on $^1$H-NMR spectra and infrared spectra. According to previous reports, barbiturates interacted with phospholipid through intermolecular hydrogen bonds. We also investigated thi observation using dipalmitoyl-phosphatidylcholine (DPPC) as phospholipid in deuterochloroform, and characterized quantitatively. Also, the observed drug could interact with cholesterol which is one of the major components of biomembranes through hydrogen bonds. It was the carbonyl groups of barbiturate and the hydroxyl group of cholesterol that formed hydrogen bond complex. In addition to spectroscopic studies, we investigated the direct effect of phenobarbital on lipid multibilayer vesicles, whose compositions were varied, by calorimetric method. Phenobarbital caused a reduction in the temperature of phase transition of vesicles. These studies may provided a basis for interpreting the mode of action of barbiturates.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.221.1-221.1
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• 2003

This research was designed to investigate the effects of Bassica oleracea L. (BO) fractions on the membrane fluidity of the liposomal phospholipid membranes. The sample BO was extracted and fractionated to six different types. methanol(BOM), hexane(BOMH). ethylether(BOMEE), etylacetate(BOMEA), butanol(BOMB) and aqueous(BOMA) fractions. The fluidity of dipalmitoylphosphatidylcholine(DPPC) liposomal membranes incorporated with BO fraction was measured by means of high-sensitivity differential scanning calorimetry(DSC). (omitted)

• 약학회지
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• 제42권3호
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• pp.265-274
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• 1998

In order to attain a sustained release at targeted organs in a prolonged time which can reduce the side effects and maximize the therapeutic effect, aclarubicin (ACL) was entrap ped into liposomes of different lipid compositions using Microfluidizer, and dry liposomes were prepared by lyophilization. The dry aclarubicin-entrapped liposomes were evaluated in terms of mean particle size and size distribution, entrapment efficiency and in vitro drug release profile. The Entrapment efficiency of liposome, when the concentration of aclarubicin and lipid were 0.5 to 1.0mg/ml and $200{\mu}mol$/ml, respectively, was over 80% using Microfluidizer, in contrast to 70% of entrapment efficiency using hand-shaking method. Mean particle size and size distribution of aclarubicin-entrapped liposomes of various lipid compositions did not change considerably by the freeze drying. The range of particle size was between 80 and 200nm. Among aclarubicin-entrapped liposomes, ACL-liposome of PC/DPPC/CH0L/TA displayed the most significant sustained release. The addition of DPPC appeared to be favorable for the control of release. In general, aclarubicin entrapped in liposomes was less stable than free aclarubicin either in pH 7.4 phosphate buffer or in human plasma. Formulation I($t_{1/2}$, 20.3 hr) devoid of lipid additive was the most unstable in the phosphate-buffer solution while formulation II($t_{1/2}$, 40.7 hr) with cardiolipin was the most stable. Half lives of aclarubicin-entrapped liposomes in human plasma were 43.2, 50.7, 35.9 and 35.3 hr for formulation I. II, III and IV, respectively, in contrast to 57.8 hr for free aclarubicin.

• Archives of Pharmacal Research
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• 제16권2호
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• pp.129-133
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• 1993

Temperature sensitive liposomes(TSL) containing adriamycin (ADM) and cytarabine (Ara-C) were prepared. ADM and Ara-C were selected as model compounds of amphiphilic and hydrophilic drug, respectively. Encapsulation efficiency of ADM entrapped into TSL was about twice greater than that of Ara-C. It might be due to different polarity of the drug, Lipid compositions of TSL had no effect on the encapsulation efficiency of drugs. Thermal behavior of TSL using a differential scanning calorimetry (DSC) was also investigated. Phase transition of TSL using a differential scanning calorimetry (DSC) was also investigated. Phase transition temperature $(T_c)$ of TSL was dependent on the lipid compositions of TSL ADM broadened thermogram of TSL but Ara-C did not. However, $T_c$ of TSL was not changed by any drug. Release rate of drugs was highly dependent on temperature. The release profile of ADM was similar to that of Ara-C. The maximum release rate of drugs from TSL was occurred at the near $T_c$ and observed at $39-41^\circ{C}$ for DPPC (Dipalmitoylphosphatidylcholine) only, $52-54^\circ{C}$ for DPPC and DSPC (1:1), respectively. Effect of human serum alburmin (HAA) on the release rate of ADM was investigated. HSA had no significant effect on the release of ADM below $T_c$. However, ADM release from TSL was increased at the near and above $T_c$. The HSA-induced leakage of drug may result from the interaction of liposomal constituents with HSA structure at the near TEX>$4^\circ{C}$. From the fact that the release profiles of ADM from freshly prepared TSL and stored TSL for 1 week at TEX>$4^\circ{C}$ was not changed, the TSL was considered to be stable for at least 1 week at TEX>$4^\circ{C}$. Based on these findings, TSL may be useful to deliver drugs to preheated target sites due to its thermal behaviors.

• 대한방사성의약품학회지
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• 제3권1호
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• pp.25-31
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• 2017

Liposomes are defined as spherical, self-closed structures formed by lipid bilayers containing aqueous phase. Most liposomes are composed of various amphipathic lipids such as phospholipids and cholesterol. We used amphipathic lipids (DPPC, DPPG) as liposome components and prepared around 100 nm liposomes by standard extrusion method. Nuclear/MR dual imaging agents based on liposome platform were prepared by adding radioactive $^{131}I$-HIB (hexadecyl-4-tributylstannylbenzoate) and Gd-DTPA into liposome bilayer and inside liposome, respectively. Gamma camera and MR imaging both showed signal increases in liver.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.113-117
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• 1995

The mechanism of the displacement current generation for stimulation transmit observed in the present displacement current measurement and theoretically analysed. The orientational change of molecules in monolayers was discussed on the basis of the Maxwell-displacement-current obtained. Maxwell displacement current was generated from monolayers on a water surface by monolayerr compression, and it measuring technique has been applied to the study of monolayers of Dipalmitoylphosphatidyl choline (L-${\alpha}$-DPPC). Finally, We measured that differential thermal analysis(DTA) of sample. Displacement current was generated when the area per molecule about 180${\AA}$$^2$in low pressure, and it was generated when the area per molecule about 110${\AA}$$^2$in high pressure. A result of DTA was showed that temperature at 124.6$^{\circ}C$.

• 한국식품영양과학회지
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• 제27권3호
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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.

• Archives of Pharmacal Research
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• 제19권2호
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• pp.95-99
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• 1996

Four N-adamantyl n-alkanamides were prepared by amide condensation reaction between amantadine and n-alkanoic acid. Their enhancing activity on the penetration of ibuprofen through rabbit skin from petrolatum ointment was evaluated in in-vivo experiment. The experiments showed that the compounds have a strong transdermal penetration-enhancing activity, and their activities were comparable with that of Azone. The measurements of the fluorescence polarization of DP[-i-labelled DPPC liposomes showed that these compounds considerablly decreased the phase transition temperature of the liposomes. The mechanism of the transdermal penetration-enhancing activity of the compounds was ascribed to the reduction of the resistance to drug flux of the stratum corneum lipid layers due to the loose packing of the layers when the bulk head group of the enhancers inserts into the layers.