• Bulletin of the Korean Chemical Society
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• v.28 no.1
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• pp.108-114
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• 2007

The lyotropic behaviors to form the structure of distearoylphosphatidylcholine (DSPC)-based liquid crystal (LC) hydrated by only propylene glycol (PG) without water were examined by differential scanning calorimetry (DSC), X-ray diffractions (XRD), polarized microscope (PM) and transmission electron microscope (TEM). By increasing the amount of PG instead of water, it showed the phase transition to be gradually changed from anisotropic structures to other structures more close to isotropic ones and their appearance to be changed from solid-like states to liquid-like ones with more fluidity. Below 50% w/w PG, the mixtures of DSPC and PG resulted in no direct observation of LC structure through PM because they were very close to solid-states. From 55% w/w to 90% w/w of PG, the dense lamella crystalline structures were observed through PM, and their thickness and area decreased as the content of PG increased. Measured by DSC with heating process, the main phase transition from α -lamella phase to isotropic phase appeared from 52.89 °C to 47.41 °C to show linearly decreasing behaviors because PG affects the hydrophobic region of DSPC-based lamella phase. The repeating distance of the lamella phase and the interlayer distance between bilayers were calculated with XRDs and the average number of bilayers related to the thickness in LC structure was approximately estimated by combining with TEM results. The WAXS and DSC measurements showed that all of PG molecules contributed to swelling both the lipid layer in the edge region of lamella phase close to phosphate groups and the interlayer between bilayers below 90% w/w of PG. The phase and thermal behaviors were found to depend on the amount of PG used by means of dissolving DSPC as a phospholipid and rearranging its structure. Instead of water, the inducement of PG as a polar solvent in solid-lamella phase is discussed in terms of the swelling effect of PG for DSPC-based lamella membrane.

• YAKHAK HOEJI
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• v.44 no.3
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• pp.251-256
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• 2000

Sterically stabilized liposomes (SSL) composed of distearoylphosphatidylcholine, cholesterol, dicetylphosphate and distearoylphosphatiodylethanolamine-N-poly(ethyleneglycol) 2000 (DSPE-PEG 2000) were made by reverse phase evaporation method to prolong biological half-life and decrease toxic side effect of drug. Streptozocin (572), a water-soluble antitumor agent with short half-life, was selected as a model drug. The size of SSL was controlled by polycarbonate extrusion to 100 nm which is adequate size for long circulation in plasma. The release rate of drugs from SSL in PBS was evaluated. And the stability of STZ-containing liposomes against drug leakage into rat plasma was evaluated in order to investigate the interaction of liposome and plasma protein. Incorporation of DSPE-PEG 2000 into conventional liposomes significantly decreased the drug leakage into rat plasma.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.2131-2135
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• 2013

Background: To evaluate the efficacy and safety of distearoylphosphatidylcholine pegylated liposomal doxorubicin (DPLD) combined with carboplatin for the treatment of platinum resistant or refractory epithelial ovarian cancer (EOC) or fallopian tube cancer. Materials and Methods: A retrospective analysis of women who received DPLD with carboplatin for recurrent EOC or fallopian tube cancer in King Chulalongkorn Memorial Hospital Thailand from January 2006 to August 2011 was conducted. Patients were identified from the medical records and data on demographic factors, stage, histology, surgical findings, cytoreduction status, and prior chemotherapies were abstracted. The efficacy and toxicity of DPLD/carboplatin were evaluated. Progression-free (PFS) and overall survival (OS) were estimated by the Kaplan-Meier method. Results: A total of 65 patients, 64 with platinum resistant or refractory epithelial ovarian cancer and 1 with fallopian tube cancer, were enrolled. DPLD and carboplatin were given for an average of 4.46 cycles per patient with a total of 273 cycles. Among the 65 evaluable patients, 0% achieved CR, 7.69% PR, 15.4% SD and 76.% PD. The overall response rate was 23.1%. With a median follow-up of 27.4 months, the median progression-free and median overall survival in the 36 patients was 4.46 months and 8.76 months respectively. In the aspect of side effects, palmar-plantar erythrodysesthesia (PPE) occurred in 33.3% (Grade I 22.2%, Grade II 11.1%) and mucositis in 41.7% (Grade I 27.8%, Grade II 13.9%) of all treatment cycles, all Grade 1 or 2. Anemia, leukopenia and thrombocytopenia occurred in 58.3% (Grade I 41.7%, Grade II 16.7%), 66.7% (Grade I 47.2%, Grade II 19.4%), and 22.2% (Grade I 16.6%, Grade II 5.56%) of cycle respectively, and were mostly Grade 1 or 2. Conclusions: DPLD, the second-generation PLD drug combined with carboplatin every 4 weeks, is effective and has low toxicity for treatment of patients with recurrent platinum-resistant or refractory epithelial ovarian cancer.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1165-1171
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• 2010

The lyotropic mesomorphism of lamellar liquid crystalline phase was examined by observing the swelling behavior of Distearoylphosphatidylcholine(DSPC) in glycerin and panthenol without water. The lyotropic mesomorphism was examined by using DSC, XRDs and Cryo-SEM. Increase of two polar solvents under non-hydrous condition showed distinctive differences in the lyotropic mesomorphism from forming different anisotropic structures with DSPC. Glycerin did not affect to the crystalline region of lamellar phase, whereas typical swelling mesomorphism was shown in the noncrystalline region. In contrast, panthenol showed some effect on the crystalline region, but common swelling mesomorphism was found in the non-crystalline region. In this case, the isopropyl and propyl groups in panthenol were the main factor to affect to the lipophilic domain in the crystalline region of lamellar phase. Also, it was found that the formation of well-arranged lamellar structure only by introducing glycerin and panthenol as a solvent without water, was possible. These results were confirmed by examination of the swelling mesomorphism of liquid crystal membrane triggered by introducing the two polar solvents.

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.93-97
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• 2002

Poly(ethylene glycol)-phosphatidylethanolamine conjugate (PEG-PE) has been used in preparing longcirculating liposomes. As a substitute for PEG-PE which can also be used in the long-circulating liposome formualtions, but can be prepared more readily with a lower cost, PEG-Phe-Chol was synthesized from PEG, phenylalanine, and cholesterol. The addition of the PEG derivative to distearoylphosphatidylcholine (DSPC) led to the formation of mixed micelles as well as liposomes when the derivative content was 10 mol% or greater. On the other hand, the addition of just 5 mol% PEG-Phe-Chol to dioleoylphosphatidylethanolamine (DOPE) generated mixed micelles as well as liposomes, but the formation of mixed micelles was completely inhibited by the addition of cholesterol. The leakage of entrapped calcein out of DOPE/cholesterol (7/3) liposomes containing 5 mol% PEG-Phe-Chol was about 45% during the incubation time for 24 h in 50% rabbit plasma, which was similar to that of the same liposomes containing 5 mol% PEG-dipalmitoylphosphatidylethanolamine (DPPE) under the identical conditions.

• Archives of Pharmacal Research
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• v.23 no.2
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• pp.167-171
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• 2000

We have investigated the in vitro cytotoxic effect of liposome-encapsulated N-(phospho-nacetyl)-L-aspartic acid (PALA) against C-26 murine colon cancer cells, and have compared it in this regard to free PALA. Three different PALA-containing liposomal formulations using distearoylphosphatidylcholine (DSPC), distearoylphosphatidylglycerol (DSPG), and polyethyle-neglycol-derivatized distearoylphosphatidylethanolamine (PEG-DSPE) were made and their cytotoxicity was measured. In 72 hr continuous exposure experiment with C-26 cells, the 50% growth inhibitory concentration ($IC_50$) of DSPG-PALA liposome formulation was $0.09\mu\$, which showed about 65-fold more potent than unencapsulated free PALA ($5.1\mu\$). Similar degree of increase in cytotoxicity was also observed in 1 hr exposure experiment. However the $IC_50$ of PEG-DSPE-PALA liposome and DSPC-PALA liposome were $10.7\mu\$and $11.8\mu\$respectively, which showed slightly less potent than unencapsulated free PALA. Physical characteristics of PALA-liposomes, such as the size and drug:lipid ratio were also determined. In conclusion, negatively-charged DSPG-PALA liposome showed the highest cytotoxic effect among tested on the C-26 cells in vitro.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.1021-1030
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• 2007

The effects of the creamide III (CER3) and cholesterol (CHOL) on the structure of a non-hydrous distearoyl phosphatidylcholine (DSPC)-based lamellar liquid crystal (LC) hydrated by only propylene glycol (PG) without water were investigated by differential scanning calorimetry (DSC), X-ray diffractions (XRDs), and polarized microscope (PM). As soon as CER3 was incorporated into the lamellar phase, the characteristic LPP was appeared as well as the characteristic SPP, and the formation of separated CER3 crystalline phase was observed depending upon the increase of CER3 content by XRDs. Also, by DSC, it was shown that the increase of CER3 made the monotectic thermal transition be changed to the eutectic thermal transition which indicates the formation of separated CER3 crystalline phases and the main transition temperatures (Tc1) to be gradually decreased and the enthalpy change (ΔH) to be linearly increased. Incorporating CHOL, the formation of LPP and SPP showed almost similar behaviors to CER3, but incorporating small amounts of CHOL showed the characteristic peaks of CHOL which meant the existence of crystalline CHOL phase due to the immiscibility of CHOL with DSPC swollen by PG differently from CER3, and increasing CHOL made the intensity of the 1st order diffraction for LPP weakened as well as the intensities of the characteristic diffractions for DSPC. Also, in the results of DSC, it showed more complex thermal behaviors having several Tc than CER3 due to its bulky chemical structure. In the present study, the inducement of CER3 and CHOL as other lipids present in human stratum corneum (SC) into a non-hydrous lamellar phase is discussed in terms of the influence on their structural and thermal transition.