• 한국생물공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.816-820
• /
• 2005

Polysaccharide-based dressings have increasingly become viable alternatives to somewhat less biocompatible and often problematic cotton or viscose gauzes traditionally used for wound dressings. Polysaccharide which is particularly abundunt in Agaricus blazei Murill is known as the bioactive materials. Polysaccharide extracted from Agaricus blazei Murill enhances the recovery of the damaged epidermal tissue and the production of epithelial cell growth factors which are necessary to heal the burn and wound on the epidermal tissue. In this study, the biopolymer delivery system of polysaccharide extracted from Agaricus blazei Murill into epidermal tissue was elucidated using the skin permeating enhancer in vitro. The enhancing effects of various penetration enhancers and some other enhancers on the permeation of ${\beta}-glucan$ were evaluated using Franz diffusion cell. Permeation of polysaccharide in nomal and burn skin was compared. Polysaccharide was studied for the burn and wound healing activity in the epidermal tissue on rats.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.48-49
• /
• 2006

The incorporation of heparin to biomaterials has been widely studied to improve the biocompatibility (blood and cell) of biomaterials surfaces. In our laboratory, various kinds of heparinized polymers including heparinized thermosensitive polymers ($Tetronic^{(R)}$-PLA(PCL)-heparin copolymers) and star-shaped PLA-heparin copolymers have been developed as a novel blood/cell compatible material. These heparinized polymers have demonstrated their unique properties due to bound heparin, resulting in improved biocompatibility. These heparinized bioactive polymers can be applied as blood and tissue compatible biodegradable materials in variable medical application such as tissue engineering and drug delivery system.

• CELLMED
• /
• v.11 no.1
• /
• pp.6.1-6.7
• /
• 2021

In situ gelling devices, as they enter the body, are dosage forms in the shape of the sol but turn into gel types under physiological circumstances. Transition from sol to gel is contingent on one or a mixture of diverse stimuli, such as transition of pH control of temperature, irradiation by UV, by the occurrence of certain ions or molecules. Such characteristic features may be commonly employed in drug delivery systems for the production of bioactive molecules for continuous delivery vehicles. The technique of in situ gelling has been shown to be impactful in enhancing the potency of local or systemic drugs supplied by non-parenteral pathways, increasing their period of residence at the absorption site. Formulation efficacy is further improved with the use of mucoadhesive agents or the use of polymers with both in situ gelling properties and the ability to bind with the mucosa/mucus. The most popular and common approach in recent years has provided by the use of polymers with different in situ gelation mechanisms for synergistic action between polymers in the same formulation. In situ gelling medicine systems in recent decades have received considerable interest. Until administration, it is in a sol-zone and is able to form gels in response to various endogenous factors, for e.g elevated temperature, pH changes and ions. Such systems can be used in various ways for local or systemic supply of drugs and successfully also as vehicles for drug-induced nano- and micro-particles. In this review we will discuss about various aspects about use of these in situ gels as novel drug delivery systems.

• Journal of Pharmaceutical Investigation
• /
• v.35 no.4
• /
• pp.233-241
• /
• 2005

Ursolic acid (UA), a bioactive triterpene acid, has been known to increase collagen content in human skin in addition to other actions such as anti-inflammatory, skin-tumor prevention and anti-invasion. However, it is poorly soluble in water. Therefore, we firstly prepared microemulsion system with benzyl alcohol, ethanol and Cremophor EL, RH 40 and Brij 35 as surfactant in order to increase solubility of UA and then prepared microemulsion was dispersed in o/w cream base for the topical delivery of UA in an effort to improve anti-wrinkle effect. The pseudo-ternary phase diagrams were developed and various microemulsion formulations were prepared using benzyl alcohol as an oil, Cremophor EL, RH 40 and Brij 35 as a surfactant. The droplet size of microemulsions was characterized by dynamic light scattering. The accumulation of VA in the skin from topical cream was evaluated in vitro using hairless mouse skins. The mean droplet size was $26.8{\pm}6.6$ nm for microemulsions II with Cremophor EL. All UA creams showed pseudoplastic flow and hysterisis loop in their rheogram, depending on the type of materials added in topical creams. The in vitro accumulation data demonstrated the UA topical cream prepared with the combination of Poloxamer 407 and Xanthan gum as a copolymer showed higher accumulation percentage than those prepared with either Poloxamer 407 or Xanthan gum. These results suggest that UA topical cream using microemulsion systems may be promising for the topical delivery of UA.

• Macromolecular Research
• /
• v.11 no.4
• /
• pp.207-223
• /
• 2003

For last five years, we are developing the novel local drug delivery devices using biodegradable polymers, especially polylactide (PLA) and poly(D,L-lactide-co-glycolide) (PLGA) due to its relatively good biocompatibility, easily controlled biodegradability, good processability and only FDA approved synthetic degradable polymers. The relationship between various kinds of drug [water soluble small molecule drugs: gentamicin sulfate (GS), fentanyl citrate (FC), BCNU, azidothymidine (AZT), pamidronate (ADP), $1,25(OH)_2$ vitamin $D_3$, water insoluble small molecule drugs: fentanyl, ipriflavone (IP) and nifedipine, and water soluble large peptide molecule drug: nerve growth factor (NGF), and Japanese encephalitis virus (JEV)], different types of geometrical devices [microspheres (MSs), microcapsule, nanoparticle, wafers, pellet, beads, multiple-layered beads, implants, fiber, scaffolds, and films], and pharmacological activity are proposed and discussed for the application of pharmaceutics and tissue engineering. Also, local drug delivery devices proposed in this work are introduced in view of preparation method, drug release behavior, biocompatibility, pharmacological effect, and animal studies. In conclusion, we can control the drug release profiles varying with the preparation, formulation and geometrical parameters. Moreover, any types of drug were successfully applicable to achieve linear sustained release from short period ($1{\sim}3$ days) to long period (over 2 months). It is very important to design a suitable formulation for the wanting period of bioactive molecules loaded in biodegradable polymers for the local delivery of drug. The drug release is affected by many factors such as hydrophilicity of drug, electric charge of drug, drug loading amount, polymer molecular weight, the monomer composition, the size of implants, the applied fabrication techniques, and so on. It is well known that the commercialization of new drug needs a lot of cost of money (average: over 10 million US dollar per one drug) and time (average: above 9 years) whereas the development of DDS and high effective generic drug might be need relatively low investment with a short time period. Also, one core technology of DDS can be applicable to many drugs for the market needs. From these reasons, the DDS research on potent generic drugs might be suitable for less risk and high return.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.2
• /
• pp.343-347
• /
• 2009

In this study, the surface of inorganic fine powders is hybridized with nanovesicles containing tocopheryl acetate prepared with hydrogenated lecithin via a coating process. From AFM and SEM analyses it is found that the surface of the nanovesicle-coated fine powders lost their traditional topology and improved in terms of their roughness, skewness, and kurtosis. In addition, TEM observations revealed the formation of a 5 nm thick coating layer on the surface of the fine powders. These hybridized powders, in which bioactive materials such as tocopheryl acetate can be embedded, can be employed as a part of a drug delivery system due to their special ability to control release rate and temperature selectivity. Physical properties of the powders, i.e., the different angle and friction coefficient, were excellent.

• Applied Chemistry for Engineering
• /
• v.21 no.6
• /
• pp.593-602
• /
• 2010

Chitosan as a natural polymer has superior physicochemical properties such as biocompatibility, biodegradability and nontoxicity, but application of chitosan for therapy of cancer and gene related-disease has been limited by poor solubility in aqueous solution. Therefore, low molecular weight water-soluble chitosan (LMWSC) with high reactivity and strong positive charge can be applied as a delivery system having function to carry in the specific tissue the bioactive material like poor solubility drug, or therapeutic gene and developed as a therapeutic system having good therapeutic efficiency. The most important factor for therapy of various diseases is to reveal the antigen or receptor expressed in specific lesion tissue and the antibody and ligand which can bind with antigen is to introduce at the biomaterials for enhancement the therapeutic efficiency. The studies for cationic synthetic polymer as drug or gene delivery have been actively performed, but it has many problems such as toxicity in the body, therapeutic efficiency. From this point of view, this article demonstrated the introduction of functional groups to target the specific tissue and therapeutic strategy using the modification of LMWSC with free-amine group. The development of these delivery system will provide a positive vision for cancer therapy.

• Asian-Australasian Journal of Animal Sciences
• /
• v.28 no.3
• /
• pp.420-427
• /
• 2015

It is necessary to understand the cellular uptake and cytotoxicity of food-grade delivery systems, such as ${\beta}$-lactoglobulin (${\beta}$-lg) nanoparticles, for the application of bioactive compounds to functional foods. The objectives of this study were to investigate the relationships between the physicochemical properties of ${\beta}$-lg nanoparticles, such as particle size and zeta-potential value, and their cellular uptakes and cytotoxicity in Caco-2 cells. Physicochemical properties of ${\beta}$-lg nanoparticles were evaluated using particle size analyzer. Flow cytometry and confocal laser scanning microscopy were used to investigate cellular uptake and cytotoxicity of ${\beta}$-lg nanoparticles. The ${\beta}$-lg nanoparticles with various particle sizes (98 to 192 nm) and zeta-potential values (-14.8 to -17.6 mV) were successfully formed. A decrease in heating temperature from $70^{\circ}C$ to $60^{\circ}C$ resulted in a decrease in the particle size and an increase in the zeta-potential value of ${\beta}$-lg nanoparticles. Non-cytotoxicity was observed in Caco-2 cells treated with ${\beta}$-lg nanoparticles. There was an increase in cellular uptake of ${\beta}$-lg nanoparticles with a decrease in particle size and an increase in zeta-potential value. Cellular uptake ${\beta}$-lg nanoparticles was negatively correlated with particle size and positively correlated with zeta-potential value. Therefore, these results suggest that the particle size and zeta-potential value of ${\beta}$-lg nanoparticles play an important role in the cellular uptake. The ${\beta}$-lg nanoparticles can be used as a delivery system in foods due to its high cellular uptake and non-cytotoxicity.

• Applied Chemistry for Engineering
• /
• v.19 no.5
• /
• pp.457-465
• /
• 2008

Development of various medical systems was accomplished through the progress of biotechnological method for therapy of human diseases. Furthermore, drug delivery systems have been investigated to carry the bioactive materials such as drug or gene in the body effectively. The most important thing in this system is to develop biomedical polymers having biocompatibility, biodegradability, and non-toxicity. Chitosan, a natural polymer, has been importantly considered as biomedical materials due to its good biocompatibility and various bio-active characteristics. Since the property of chitosan is differently explained according to the crystalline structures of chitin, the study for structural analysis of chitin has to proceed to apply as a biomaterial. From this point of view, this article introduced the analysis of crystalline structural of chitin, general property of chitosan and potential characteristics of low molecular weight water-soluble chitosan (LMWSC) as a biomaterials. Furthermore, chemical modification of LMWSC using various functional groups was also performed to enhance its bioavailability and emphasize their potential as drug delivery carriers (DDS).

• Macromolecular Research
• /
• v.11 no.5
• /
• pp.334-340
• /
• 2003

In order to fabricate new sustained delivery device of nerve growth factor (NGF), we developed NGF-loaded biodegradable poly(L-lactide-co-glycolide) (PLGA, the mole ratio of lactide to glycolide 75:25, molecular weight: 83,000 and 43,000 g/mole, respectively) film by novel and simple sandwich solvent casting method for the possibility of the application of neural tissue engineering. PLGA was copolymerized by direct condensation reaction and the molecular weight was controlled by reaction time. Released behavior of NGF from NGF-loaded films was characterized by enzyme linked immunosorbent assay (ELISA) and degradation characteristics were observed by scanning electron microscopy (SEM) and gel permeation chromatography (GPC). The bioactivity of released NGF was identified using a rat pheochromocytoma (PC-12) cell based bioassay. The release of NGF from the NGF-loaded PLGA films was prolonged over 35 days with zero-order rate of 0.5-0.8 ng NGF/day without initial burst and could be controlled by the variations of molecular weight and NGF loading amount. After 7 days NGF released in phosphate buffered saline and PC-12 cell cultured on the NGF-loaded PLGA film for 3 days. The released NGF stimulated neurite sprouting in cultured PC-12 cells, that is to say, the remained NGF in the NGF/PLGA film at 37 $^{\circ}C$ for 7 days was still bioactive. This study suggested that NGF-loaded PLGA sandwich film is released the desired period in delivery system and useful neuronal growth culture as nerve contact guidance tube for the application of neural tissue engineering.