• Bulletin of the Korean Chemical Society
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• 제28권1호
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• pp.99-102
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• 2007

To prepare freeze-dried ascorbyl palmitate (AsP)-containing liposome which can protect the drug from moisture attack and be used instantly by mixing with water for anti-aging and skin whitening therapy, AsP was encapsulated into liposomes and freeze-dried with trehalose. The freeze-dried liposome formulations were characterized by measuring water contents, particle size, time required for complete reconstitution. With the freeze-dried liposomes, we performed the stability test under accelerated conditions, skin permeation and localization test. The measurement of the time to perfect reconstitution showed that the freeze-dried liposomes can be changed to their initial state rapidly and short term stability test of AsP in reconstituted liposomes under accelerated conditions confirmed that the stability of AsP was considerably enhanced as compared to freshly prepared liposomes. The skin permeation and localization properties of AsP in reconstituted liposomes were not significantly different, indicating that the liposomal structures were maintained before and after freezedrying. In conclusion, the freeze-drying method provided a possible way to overcome the instability issue of AsP induced by the moisture and reproduced similar skin permeation and localization properties as shown by freshly prepared liposomes.

• Journal of Pharmaceutical Investigation
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• 제25권3호
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• pp.249-264
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• 1995

Although liposome has many advantages as a pharmaceutical dosage form, its application in the industrial field has been limited because of some problems such as preparation method, reproducibility, scale-up, stability and sterilization etc. Liposomes prepared by microemulsification method had defined size, narrow size distribution, reproducibility and high entrapment efficiency. For enhancing the stability, the dry form of liposome was recommended. These types of liposome are proliposome and freeze-dried liposome. The liposome must have some properties for preparing of freeze-dried liposome; small size $(50{\sim}200\;nm)$, narrow size distribution and cryoprotectant. In this experiment, the liposomes containing 5-Fluorouracil(5-FU) and its prodrug(pentyl-5-FU-1-acetate; PFA, hexyl-5-FU-1-acetate; HFA) were made with soybean phosphatidylcholine, cholesterol, stearylamine(SA) and dicetyl phosphate(DCP) employing hydration method or microemulsification method using $Microfluidizer^{TM}$. Both or liposome types were MLV and MEL. After preparation, freeze drying and rehydration were performed. In the process of freezing, trehalose(Tr) was added as a cryoprotectant. Their evaluation methods were as follows; entrapment efficiency, mean particle size and size distribution, dissolution test, retain of entrapment efficiency and turbidity after freeze-drying. The results are summarized as belows. The entrapment efficiency of 5-FU was dependent on total lipid concentration and cholesterol content but that of PFA and HFA was decreased when cholesterol was added. When DCP and SA were added, entrapment efficiency was decreased. As the partition coefficient of drug was increased, entrapment efficiency was increased. Under the same condition, entrapment efficiency of MEL is similar to that of MLV. The mean particle size and size distribution of MEL were smaller than those of MLV. Dissolution rates of drug from both liposome types were comparatively similar. Dissolution rates of drugs with serum and liver homogenate were faster than without these material. After preparation of liposome, free drug was removed efficiency by Dowex 50W-X4. When liposome was freeze-dried and then rehydrated in the presence of Tr, characteristics of liposome were maintained well in MEL than MLV. Tr Was used successfully as a cryoprotectant in the process of freeze drying and the optimal ratio of Tr:Lipid was 4:1(g/g).

• 대한화학회지
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• 제48권6호
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• pp.616-622
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• 2004

약물 수송체로 사용되는 리포솜은 동결 건조를 통하여 분말화 시키는 방법이 사용되어지고 있다. 리포솜 안정제로서 말토스는 동결건조된 리포솜 분말의 안정성을 향상시키고 약물 봉입률에 영향을 주는 것으로 알려져 왔다. 동결건조 전과 후의 리포솜 입자의 크기를 측정하므로서 리포솜의 안정성을 평가하였고 또한, 약물 봉입률은 모델 약물인 칼세인을 사용하여 조건에 따른 봉입양을 측정하였다. 리포솜 제조 후에 말토스를 첨가한 리포솜은 수화하는 과정에서 말토스를 첨가하여 제조한 리포솜보다 훨씬 더 안정한 것으로 확인되었다. 말토스를 첨가하지 않은 리포솜은 시간이 지남에 따라 입자의 크기가 커지는 반면, 리포솜 제조 후에 말토스를 첨가한 리포솜은 $4{\sim}37^{\circ}C$에서 30일 동안 안정하다. 또한, 말토스/지질의 물농도 비가 3과 6일 때 상대적으로 가장 높은 안정성을 보였다.

• 약학회지
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• 제42권3호
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• pp.274-274
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• 1998

Aclarubicin(ACL)-entrapped freeze dried liposomes were prepared using Microfludizer to attain a sustained release at targeted organs in a prolonged time so that it can reduce th e side effect and maximize the therapeutic effect. The freeze-dried liposomes were evaluated for pharmacokinetics, antitumor activity against Sarcoma 180, cytotoxicity against L1210 and A549 tumor cells, spleen toxicity and myelosuppressive action. The AUC0->8hr values were 122+/-42, 382+/-140, 419+/-171, 835+/-206 and 443+/-309mcg min/ml for free ACL. ACL-liposome formulation I, II, III and IV, respectively. Cytotoidcity of ACL-entrapped liposomes against L1210 and A549 tumor cells was 2-4 times higher than that of free aclarubicin. ACL-liposome formulation I(PC/CHOL/TA) showed the most potent antitumor activity against Sarcoma 180 in mice. The loss of body weight was much smaller with ACL-entrapped liposomes than free ACL after I.p. injection at a dose of 2 mg/kg/day. Compared to free ACL, ACL-entrapped liposomes expressed a lower and delayed spleen toxicity up to 5th day after I.v. administration. Myelosupperssion seemed to be lower with ACL-entrapped liposome of PC/PC-hydrate/CHOL/TA (formulation III) than free aclarubicin.

• 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%).

• 약학회지
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• 제42권3호
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• pp.275-283
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• 1998

Aclarubicin(ACL)-entrapped freeze dried liposomes were prepared using Microfludizer to attain a sustained release at targeted organs in a prolonged time so that it can reduce th e side effect and maximize the therapeutic effect. The freeze-dried liposomes were evaluated for pharmacokinetics, antitumor activity against Sarcoma 180, cytotoxicity against L1210 and A549 tumor cells, spleen toxicity and myelosuppressive action. The $AUC_{0{\rightarrow}8hr}$ values were $122{\pm}42,\;382{\pm}140,\;419{\pm}171,\;835{\pm}206\;and\;443{\pm}309{\mu}g{\cdot}min/ml$ for free ACL. ACL-liposome formulation I, II, III and IV, respectively. Cytotoidcity of ACL-entrapped liposomes against L1210 and A549 tumor cells was 2-4 times higher than that of free aclarubicin. ACL-liposome formulation I(PC/CHOL/TA) showed the most potent antitumor activity against Sarcoma 180 in mice. The loss of body weight was much smaller with ACL-entrapped liposomes than free ACL after I.p. injection at a dose of 2 mg/kg/day. Compared to free ACL, ACL-entrapped liposomes expressed a lower and delayed spleen toxicity up to 5th day after I.v. administration. Myelosupperssion seemed to be lower with ACL-entrapped liposome of PC/PC-hydrate/CHOL/TA (formulation III) than free aclarubicin.