• Proceedings of the KSME Conference
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• 2008.11b
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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.

• YAKHAK HOEJI
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• v.42 no.3
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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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• v.27 no.12
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• pp.1263-1269
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• 2004

The objective of this study was to characterize immunoliposomes carrying plasmid DNA with optimal encapsulation efficiency and antibody density. Plasmid DNA was encapsulated by the freezing/thawing method into liposomes composed of POPC (1-palmitoyl-2-oleoyl-sn-glycerol- 3-phosphocholine), DDAB (didodecyl dimethyl ammonium bromide), DSPE-PEG 2000 (distearoyl phosphatidyl ethanolamine polyethylene glycol 2000) and DSPE-PEG 2000-maleimide. The liposomes carrying plasmid DNA were extruded through two stacked polycarbonate filters, of different pore size, to control the liposome size. Then, rat IgG molecules were conjugated to the liposomes. The immunoliposomes containing plasmid DNA were separated from the free plasmid DNA and unconjugated IgG by Sepharose CL-4B column chromatography. The DNA amount encapsulated was affected by DDAB (cationic lipid) concentration, the initial amount of plasmid DNA between 10 ${\mu}g$ and 200 ${\mu}g$, the total lipid amount and plasmid DNA size, but not significantly by liposome size. By varying the ratio of DSPE-PEG 2000-maleimide to IgG, the number of IgG molecules per liposome was changed significantly.

• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.231-236
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• 2011

The aim of this study was to investigate the effect of charge carrier lipid on the skin penetration, retention, and hair growth of topically applied finasteride-containing liposomes. Finasteride-containing liposomes were prepared by traditional thin film hydration method using Phospholipon$^{(R)}$ 85 G and cholesterol with or without charge carrier lipid (1,2 dimyristoyl-sn-glycero-3-phosphate or 1,2-dioleoyl-trimethylammonium-propane for anionic and cationic charge, respectively). Freshly prepared finasteride-containing liposome suspension was applied on the hairless mouse skin, and skin penetration and retention were measured using Keshary-Chien diffusion cell. Non-liposomal formulation (ethanol 10% solution containing 0.5 mg/ml of FNS) was also used as a control. The amount of finasteride in the diffusion cell and mouse skin was measured by HPLC. The hair growth was evaluated using depilated male C57BL/6N mice. Mean particle size of all finasteride-containing liposomes was less than a micron, and polydispersity index revealed size homogeneity. Skin penetration and retention studies showed that significantly less amount of finasteride was penetrated when applied as anionic liposome while more amount of the drug was retained. Specifically, in liposome prepared with 10% anionic charge carrier lipid, penetration was 12.99 ${\mu}g/cm^2$ while retention was 79.23 ${\mu}g/cm^2$ after 24 h of application. In hair growth study, finasteride-containing anionic liposomes showed moderate efficacy, but the efficacy was not found when applied as cationic liposomes. In conclusion, topical application of finasteride using anionic liposome formulation appears to be useful option for the treatment of androgenetic alopecia to avoid systemic side effects of the drug.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.1
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• pp.15-31
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• 2012

In our previous studies, the antioxidant, anti-aging, and antibacterial activities of Persicaria hydropipier L. extract, and the moisturizing effect of cream containing P. hydropipier extract were investigated. In this study, the cellular protective effects of P. hydropipier extract and isoquercitrin, main component from P. hydropipier in $^1O_2$-induced photohemolysis of human erythrocytes and ultraviolet B (UVB)-exposed HaCaT cells were investigated. Liposomes such as ethosome and elastic liposome for enhanced transdermal delivery were prepared. Size, loading efficiency, stability, and cumulative permeated amounts of ethosomes and elastic liposomes were evaluated. P. hydropipier extract and isoquercitrin showed more prominent cellular protective effect than (+)-${\alpha}$-tocopherol, known as lipid antioxidant at $5{\mu}g/mL$. P. hydropipier extract didn't show any characteristics of cytotoxicity at $50{\mu}g/mL$. When HaCaT cells were exposed to a single large dose ($400mJ/cm^2$) of UVB, the extract protected the cells against UVB radiation in a concentration dependent manner ($12.5{\sim}50{\mu}g/mL$). Cell viability of HaCaT cells exposed to UVB $400mJ/cm^2$ was increased by treatment with P. hydropipier extract or isoquercitrin from 36 % (cell viability of positve control groups) to 90 % (cell viability of P. hydropipier extract or isoquercitrin- treated groups). The size of 0.04 % P. hydropiper extract loaded ethosomes was 173.0 nm and the loading efficiency was 55.58 %. 0.04 % P. hydropiper extract loaded ethosomes were stable with as monodisperse particles for 1 week. The ethosome exhibited more skin permeability than general liposome and ethanol solution. The optimal ratio of lipid to surfactant ($Tego^{(R)}$ care 450) of 0.1 % P. hydropiper extract loaded elastic liposomes was observed to be 95 : 5. Vesicle size of 0.1 % P. hydropiper extract loaded elastic liposome was 176.5 nm. The deformability index of the elastic liposome was 16.4. The loading efficiency was 68.8 %. The elastic liposome containing P. hydropiper extract showed more skin permeability than liposome without surfactant ($Tego^{(R)}$ care 450).

• Journal of Pharmaceutical Investigation
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• v.33 no.3
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• pp.209-213
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• 2003

The objective of this study was to construct the pegylated liposomes containing plasmid DNA with optimal encapsulation efficiency. Plasmid DNA $(pGL2\;clone\;753,\;{\sim}6\;kb)$ was encapsulated by the freeze/thawing method into liposomes composed of 1-palmitoyl-2-oleyl-sn-glycerol-3-phosphocholine (POPC), didodecyl dimethyl ammonium bromide (DDAB), distearoylphosphatidyl ethanolamine polyethylene glycol 2000 (DSPE-PEG 2000) and DSPE-PEG 2000-male-imide. The liposomes containing plasmid DNA were then extruded through two stacked polycarbonate filters with series of different pore sizes to control the liposome size. The plasmid DNA entrapped in the liposomes was separated from free plasmid DNA by Sephadex CL-4B column chromatography. The decreased pore size of polycarbonate filters resulted in the decreased size of liposomes. The encapsulation efficiency was markedly affected by the cationic lipid (DDAB) concentration, but to a low degree by the size of liposomes and by the amount of plasmid DNA.

• Journal of the Korean Chemical Society
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• v.57 no.4
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• pp.493-498
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• 2013

Liposomes, which can deliver payload at target site, have been studied as drug carrier. However, conventional liposomes have limitation for drug release at target site. Therefore, we developed hydroxyapatite (HA) coated ultrasound sensitive liposomes to increase drug release at target site and to enhance stability in blood stream. Control liposome was prepared using hydrogenated soy phosphatidylcholine (HSPC) and cholesterol, and then we assessed HA coating on the surface of control liposomes using calcium acetate, phosphoric acid, and 25% ammonium solution. Doxorubicin was used as a model drug. Size of HA coated liposomes was 120 nm and encapsulation efficiency of doxorubicin in liposomes was up to 95%. Size of HA coated liposomes are not changed in 30% serum solution, however, the control liposomes was 1.4 fold increased. After ultrasound triggered drug release from liposomes, intracellular efficiency of drug released from HA coated liposomes was 3 fold increased compared to control liposomes. In this study, we developed ultrasound sensitive liposomes to enhance drug release, which will be applied in controlled drug release at disease site.

• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.43-50
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• 2007

Liposomes having particle size from several tens to hundreds nanometers are efficient carriers for injectable drug delivery. Enhancement of liposome stability in bloodstream has been studied because of its relatively short circulation time and fast clearance from human body by reticuloendothelial system (RES) in blood vessel. In this study, new disaccharide-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) derivatives in which lactose or sucrose as the disaccharide molecule was conjugated covalently to DSPE were synthesized. Liposomes of which surface had disaccharide molecules were prepared by incorporating the disaccharide-DSPE into liposomes as one of their lipid components. Particle size of the prepared liposomes was approximately 100 nm. The liposomes of which surface were modified with the disaccharide-DSPE showed -25 mV of zeta potential value due to the presence of hydroxyl groups on their surface, while the unmodified control liposomes showed -10 mV of zeta potential value. Loading efficiency of model drug, doxorubicin, into liposomes was about 90%. Stability of the disaccharide-modified liposomes in vitro was evaluated by monitoring the amount of protein adsorption and particle size of the liposomes in serum. Disaccharide-modified liposomes were more stable in serum than unmodified control liposomes or polyethyleneglycol (PEG)-modified liposomes due to less adsorption of serum protein and hence less increase of their particle size. The liposomes of which surface was modified with disaccharide-DSPE conjugate can be used as long-circulating carriers for drugs having high toxicity or short half-life time due to their enhanced stability in blood circulatory system.

• Applied Microscopy
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• v.41 no.1
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• pp.47-53
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• 2011

Hair is an appendage of skin which protects the body from outer physical and chemical stimuli. Hair is generated from the hair follicle lying on a sunken basal layer of epidermis. Hair cycling, which regenerates hair follicles throughout the life time of the organism. Numerous kinds of factors which exist at the hair follicle have been reported to regulate hair cycling, Human growth hormone secreted from pituitary gland, initially demonstrated to accelerate organ's growth, has been reported to play a role in the biology of organ size determination. We investigated the effect of 6-histidines residues tagged at amino-terminus of human growth hormone using light and electronmicroscopic methods. Human growth hormone encapsulated in nano-liposome (LhGH) was used to find how LhGH affects hair follicle cycling of mouse (C57BL6/CrN). Distilled water as a negative control, 3% Minoxidil as a positive control, and LhGH were applied to mouse for weeks. LhGH increased the number of exposed hairs per given areas ($1mm^2$). This result was also confirmed using a different breed of mice which show natural hair loss in an old age (about 17 months after birth). When LhGH was applied for 3 weeks after natural hair loss, natural hair loss on these mice was prevented, However, the control group mice on which LhGH was not applied showed further hair loss. This result indicates that LhGH may stimulate hair cycling of mouse. In clusion, it is cleat that the LhGH increased the number of hair on mice and help the depilated skin to grow new hair follicles again.

• Applied Chemistry for Engineering
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• v.18 no.6
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• pp.625-629
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• 2007

Recently, there is a growing interest about unsaturated lecithin having excellent characteristics of skin affinity and absorbency. Accordingly, this study intended to develop a natural sulfuration material in order to enhance the stability of oxidation of unsaturated lecithin and substitute existing sulfuration materials which indicate variability and toxicity. As sulfuration components, plenol acid family, 3,5-dihydroxybenzoic acid, and flavanone were analyzed. Total polyphenol content was higher in the root extracts (133.85 mg/g) than in the fruit extracts (53.5 mg/g). Above 100 ppm polyphenol content, the free radical removal efficiency and lipid oxidation prevention of the root extracts were 20.1 and 19.2% superior compared with BHT respectively. Also, the extracts indicated high survival rate of more than 95% below 1250 ppm, showing the stability. For the stability of liposome made from an unsaturated lecithin, the root extracts were superior to the fruit extracts. Especially, 15.1 and 13.9% of sulfuration effect and zeta potential were improved with 9.3% reduced particle size compared with BHT as the control group, respectively.