• 폴리머
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• 제34권6호
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• pp.501-506
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• 2010

물에 잘 녹지 않는 고분자량의 키토산을 가수분해하여 수용성을 갖는 저분자량 키토산을 제조하였다. 키토산을 효율적인 유전자 전달체로 개발하기 위하여 항산화제의 일종인 리포산과 결합하여 빗살 형태의 공중합체를 제조하였다. 양친성을 가지는 공중합체는 수용액 상에서 자기조립을 하여 나노입자를 형성하였다. 나노입자의 평균크기는 217.6 nm이었고 유전자와 복합체를 이루었을 때의 평균크기는 170 nm로 나타났다. 새롭게 만들어진 키토산-리포산 공중합체는 낮은 세포독성을 나타내었고 순수한 키토산에 비하여 10배 정도 높은 형질 발현효율을 보여주었다.

• Advances in nano research
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• 제13권1호
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• pp.87-96
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• 2022

Drug self-delivery systems can easily realize combination drug therapy and avoid carrier-induced toxicity and immunogenicity because they do not need non-therapeutic carrier materials. So, designing appropriate drug self-delivery systems for specific diseases can settle most of the problems existing in traditional drug delivery systems. Retinal pigment epithelium is very important for the homeostasis of retina. However, it is vulnerable to oxidative damage and difficult to repair. Worse still, the antioxidants can hardly reach the retina by non-invasive administration routes due to the ocular barriers. Herein, the targeted group (folic acid) and antioxidant (melatonin) have been grafted on the surface of ZnO quantum dots to fabricate a new kind of drug self-delivery systems as a protectant via eyedrops. In this study, the negative nanoparticles with size ranging in 4~6 nm were successfully synthesized. They could easily and precisely deliver drugs to retinal pigment epithelium via eyedrops. And they realized acid degradation to controlled release of melatonin and zinc in retinal pigment epithelium cells. Consequently, the structure of retinal pigment epithelium cells were stabilized according to the expression of ZO-1 and β-catenin. Moreover, the antioxidant capacity of retinal pigment epithelium were enhanced both in health mice and photic injury mice. Therefore, such new drug self-delivery systems have great potential both in prevention and treatment of oxidative damage induced retinal diseases.

• Molecules and Cells
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• 제25권4호
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• pp.462-466
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• 2008

Adenoviruses are the most commonly used gene-delivery vectors due to the efficiency of their in vivo gene transfer. Since 1993, about 300 protocols using an adenoviral vector have been performed, although they have yet to be proven effective in clinical trials. The adenovirus-based vector has been continuously improved by modification of the adenoviral genome and capsid, and novel adenovirus-delivery systems, such as the carrier-cell delivery system, have been recently proposed. Adenovirus-based cancer gene therapy is fast becoming one component of a multi-modality treatment approach to advanced cancer, along with surgery, radiotherapy, and chemotherapy.

• 무역상무연구
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• 제77권
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• pp.1-22
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• 2018

Under CISG the places of delivery by the seller of the goods are: If the seller is not bound to deliver the goods at any other particular place and the contract of sale involves carriage of the goods, the seller has to hand the goods over to the first carrier for transmission to the buyer. However, if the contract does not involve carriage of the goods, he has to place them at the buyer's disposal at the place where, at the time of the conclusion of the contract, both the seller and the buyer knew that the goods were at, or were to be manufactured or produced. This rule applies when the contract relates to specific goods, or unidentified goods to be drawn from a specific stock or to be manufactured or produced. Finally, in ant other cases the seller has to place the goods at the buyer's disposal at the place where the seller had his place of business at the time of the conclusion of the contract. As to time of delivery, if a date is fixed by or determinable from the contract, the seller has to deliver the goods on that date. If a period for delivery is fixed by or determinable from the contract, he has to deliver the goods on any date within that period. In this way the seller chooses the specific date of delivery within that period, while circumstances indicate otherwise that the choice is to be made by the buyer. There no such date or period, the seller has to deliver the goods within a reasonable time after the conclusion of the contract. If the seller delivers the goods before such the date or period, the buyer is entitled to take delivery or refuse to take delivery. Under these backgrounds of provisions of CISG, this study first suggests the concepts of the handing over of the goods by the seller to the carrier and the placing them at the buyer's disposal. Then it goes further to looks into exactly where and when the delivery has to occur. In these context, this study more examines what happens if there is a breach of contract by the seller in connection with the delivery. That is, if the seller delivers non-conforming goods or at wrong place; what if there is a partial delivery or a premature delivery.

• Macromolecular Research
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• 제15권2호
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• pp.100-108
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• 2007

Gene therapy has become a promising strategy for the treatment of genetically based diseases, such as cancer, which are currently considered incurable. A major obstacle in the field of cancer gene therapy is the development of a safe and efficient delivery system for therapeutic gene transfer. Non-viral vectors have attracted great interest, as they are simple to prepare, stable, easy to modify and relatively safe compared to viral vectors. In this review, an insight into the strategies developed for polyethylenimine (PEI)-based non-viral vectors has been provide, including improvement of the polyplex properties by incorporating hydrophilic spacer, poly(ethylene glycol) (PEG). Moreover, this review will summarize the strategies for the tumor targeting. Specifically, a targeted polymeric gene delivery system, PEI-g-PEG-RGD, will be introduced as an efficient gene delivery vector for tumor therapy, including its functional analysis both in vitro and in vivo.

• 대한의생명과학회지
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• 제29권4호
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• pp.231-241
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• 2023

Messenger RNA (mRNA)-based vaccines and treatments have recently emerged as a promising strategy. Naked mRNA presents various limitations for direct delivery. Therefore, in this paper, Lipid Nanoparticles (LNPs) were utilized for the delivery of mRNA. Lipid nanoparticle (LNP) mRNA systems are highly effective as vaccines, but their efficacy for pulmonary delivery has not yet been fully established. Additionally, research on effective delivery systems and administration methods for vaccines is required to resolve the stability and degradation issues associated with naked mRNA delivery. This study aimed to determine mRNA delivery efficiency via the inhalation of a lipid nanoparticle (LNP) formulation designed specifically for pulmonary delivery. To this purpose, we built a library of seven LNP configurations with different lipid molar and N/P ratios and evaluated their encapsulation efficiency using gel retardation assay. Among the tested LNPs, LNP1, LNP2-2, and LNP3-2 demonstrated high transfection efficiency in vitro based on FACS analyses luciferase assays, and intracellular accumulation tests. The mRNA delivery efficiencies of the selected LNPs after inhalation and intravenous injection were compared and evaluated. LNP2-2 showed the highest mRNA expression in healthy mouse lungs when aerosolized and was found to be non-toxic. These results indicate that LNP2-2 is a promising carrier for lung mRNA delivery via inhalation.

• Journal of Pharmaceutical Investigation
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• 제39권1호
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• pp.13-18
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• 2009

Docetaxel is an anticancer agent with low aqueous solubility. More extensive clinical use of this drug is somewhat delayed due to lack of appropriate delivery vehicles. An attempt was made to adopt an o/w emulsion as the drug carrier which incorporated docetaxel in the propyleneglycerol stabilized by a mixed-emulsifier system. A suitable formulation was found in this study: 10 mg/mL docetaxel, 10% (w/v) oil blend, 4% (w/v) PG, 3% (w/v) Solutol HS 15 in 2.25% (w/v) glycerol solution. The formulated emulsion has very good stability when stored at $40^{\cird}C$, and the docetaxel containment efficiency can be maintained above 95% and the mean emulsion diameter around $10{\mu}m$ for at least 3 months. The formulated emulsion is a promising carrier for docetaxel and other lipophilic drugs.

• Macromolecular Research
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• 제14권4호
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• pp.461-465
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• 2006

Two types of injectable system using thermosensitive chitosan (chitosan-g-NIPAAm), hydrogel and microparticles (MPs)-embedded hydrogel were developed as drug carriers for controlled release and their pharmaceutical potentials were investigated. 5-Fluorouracil (5-FU)-loaded, biodegradable PLGA MPs were prepared by a double emulsion method and then simply mixed with an aqueous solution of thermosensitive chitosan at room temperature. All 5-FU release rates from the hydrogel matrix were faster than bovine serum albumin (BSA), possibly due to the difference in the molecular weight of the drugs. The 5-FU release profile from MPs-embedded hydrogel was shown to reduce the burst effect and exhibit nearly zero-order release behavior from the beginning of each initial stage. Thus, these MPs-embedded hydrogels, as well as thermosensitive chitosan hydrogel, have promising potential as an injectable drug carrier for pharmaceutical applications.

• 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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• 제35권2호
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• pp.75-80
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• 2005

A promising application of Lactococcus lactis is its use as live vehicles for production and delivery of heterologous proteins of vaccines and therapeutic substances. Because L. lactis has GRAS ('generally regarded as safe') status, we tested whether L. lactis could function as the carrier of the Ll protein of human papillomavirus (HPV) type 16. The RNA level expression of Ll gene was detected in L. Lactis. The Ll protein was expressed in L. lactis with Ll gene. The growth of strains L. lactis with an empty plasmid (pAMJ328) and L. lactis with Ll-encoding plasmid (pAMJ328-Ll) was slightly decreased in comparison with the growth of strains L. lactis (wild type). However, all the three strains of L. lactis maintained the ability to ferment sugars primarily into lactic acid, indicating that Ll protein did not affect the biochemical property of L. lactis. These results suggest that L. lactis, capable of carrying Ll protein, might be further developed as a biocompatible oral protein delivery system.