• YAKHAK HOEJI
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• v.39 no.5
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• pp.487-494
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• 1995

Solid lipid microspheres (SLMs) were prepared using various lipids and solidifying agents, in order to enhance the gastrointestinal absorption of Cyclosporine A (Cs A) which is a practically water-insoluble drug with low systemic bioavailability. Egg lecithin and HCO-60 (polyoxyethylated 60 mol, hydrogenated castor oil) were used as lipids. Stearic acid and stearyl alcohol were used as solidifying agents. Emulsion concentrates containing Cs A were prepared by mixing the melted lipid and solidifying agent with water, employing bile salts as a cosurfactant. SLMs were obtained by dispersing the warm emulsion concentrate in cold distilled water under mechanical stirring, followed by freeze drying. Physical characteristics of each SLM were investigated by particle size analysis, optical microscopy and scanning electron microscopy. Mean particle size of SLMs was in the range of 30 to 40.mu.m. The SLMs were in good appearance with spherical shape before freeze drying, but were deformed partially after freeze drying. Drug loading efficiencies of SLMs were observed as high as 80 to 90% in average. The systemic bioavailability of Cs A from different SLM formula was investigated in rats following oral administration. Cs A in whole blood was extracted and assayed by HPLC. SLMs revealed the higher bioavailabilities than the standard formula based on the marketed product. SLMs might have several advantages over standard formula for enhanced gastrointestinal absorption, controlled release properties, high loading capacity of the water-insoluble drug, and feasibility of solid dosage forms with better stability in storage.

• Journal of Microbiology and Biotechnology
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• v.29 no.7
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• pp.1009-1013
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• 2019

Polymeric nanoparticles are widely used for drug delivery due to their biodegradability property. Among the wide array of polymers, chitosan has received growing interest among researchers. It was widely used as a vehicle in polymeric nanoparticles for drug targeting. This review explored the current research on the antimicrobial activity of chitosan nanoparticles (ChNP) and the impact on the clinical applications. The antimicrobial activities of ChNP were widely reported against bacteria, fungi, yeasts and algae, in both in vivo and in vitro studies. For pharmaceutical applications, ChNP were used as antimicrobial coating for promoting wound healing, preventing infections and combating the rise of infectious disease. Besides, ChNP also exhibited significant inhibitory activities on foodborne microorganisms, particularly on fruits and vegetables. It is noteworthy that ChNP can be also applied to deliver antimicrobial drugs, which further enhance the efficiency and stability of the antimicrobial agent. The present review addresses the potential antimicrobial applications of ChNP from these few aspects.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.2
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• pp.171-176
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• 2020

Covalent organic frameworks (COFs) are porous crystalline polymers in which organic units are linked by covalent bonds and have a regular arrangement at the atomic level. Recently, the COFs have been much attention in bio-medical area such as bio-imaging, drug delivery, and therapeutics. These 2D nanoparticles are proving their value in nanomedicine due to their large surface area, functionalization through functional groups exposed on the surface, chemical stability due to covalent bonding, and high biocompatibility. The high ω-electron density and crystallinity of COFs makes it a promising candidate for bioimaging probes, and its porosity and large surface area make it possible to be utilized as a drug delivery vehicle. However, the low dispersibility in water, the cytotoxicity problems of COFs are still challenged to be solved in the future. In this regard, several efforts that increase the degree of dispersion through functionalization on the surface of COFs for the application to the biomedical field have been reported. In this review, we would like to describe the advantages and limitations of COFs for bio-imaging and anti-cancer treatment.

• Journal of Microbiology and Biotechnology
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• v.34 no.7
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• pp.1376-1384
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• 2024

Viral infectious diseases have always been a threat to human survival and quality of life, impeding the stability and progress of human society. As such, researchers have persistently focused on developing highly efficient, low-toxicity antiviral drugs, whether for acute or chronic infectious diseases. This article presents a comprehensive review of the design concepts behind virus-targeted drugs, examined through the lens of antiviral drug mechanisms. The intention is to provide a reference for the development of new, virus-targeted antiviral drugs and guide their clinical usage.

• Applied Chemistry for Engineering
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• v.35 no.5
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• pp.451-457
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• 2024

This study focused on the development of a dequalinium-containing oil-in-water (O/W) emulsion (DQE) system for delivering the mitochondria-targeted anticancer agent, curcumin. Dequalinium is a mitochondria-targeting agent with known antibacterial and anticancer properties, and its efficacy in treating malaria has been previously recognized. Structurally, dequalinium is amphiphilic, comprising hydrophobic methylene and hydrophilic quinaldinium groups. In this study, curcumin, a well-documented anticancer and antioxidant compound, was incorporated into the oil phase of an emulsion using dequalinium as the emulsifier. Castor oil, chosen for its biodegradability and high stability in the body, was used as the oil phase in this study. The curcumin-loaded DQE was prepared using ultrasonic sonication followed by homogenization. The morphology and size distribution of the emulsion particles, as assessed using nanoparticle analysis, atomic force microscopy, and transmission electron microscopy, ranged from 100-200 nm. Confocal microscopy confirmed the efficient mitochondrial targeting ability of DQE in HeLa cells. These findings establish the DQE system as a promising drug delivery platform with efficient mitochondrial targeting capabilities and the potential to encapsulate water-insoluble drugs.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.22 no.1
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• pp.29-62
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• 2018

We investigate a class of HIV infection models with two kinds of target cells: $CD4^+$ T cells and macrophages. We incorporate three distributed time delays into the models. Moreover, we consider the effect of humoral immunity on the dynamical behavior of the HIV. The viruses are produced from four types of infected cells: short-lived infected $CD4^+$T cells, long-lived chronically infected $CD4^+$T cells, short-lived infected macrophages and long-lived chronically infected macrophages. The drug efficacy is assumed to be different for the two types of target cells. The HIV-target incidence rate is given by bilinear and saturation functional response while, for the third model, both HIV-target incidence rate and neutralization rate of viruses are given by nonlinear general functions. We show that the solutions of the proposed models are nonnegative and ultimately bounded. We derive two threshold parameters which fully determine the positivity and stability of the three steady states of the models. Using Lyapunov functionals, we established the global stability of the steady states of the models. The theoretical results are confirmed by numerical simulations.

• The Journal of Korean Medicine
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• v.30 no.2
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• pp.127-132
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• 2009

Objectives: This study aimed to investigate the stability of a decoction using three herbal plants and their major components according to the storage conditions and periods. Materials and Methods: A three-herb mixture (1:1:1) of Glycyrrhiza uralensis Fischer, Artemisia capillaris Thunberg, and Poncirus trifoliata Rafinesqui was decocted and kept at room temperature ($25{\pm}2^{\circ}C$) or cold temperature ($4^{\circ}C$) for 0, 2, 4 or 8 weeks in liquid form in a plastic pack under dark conditions. At time points given, they were lyophilized. 200 mg of powdered samples were dissolved in 1 mL of 90% methanol and then applied to a high performance thin layer chromatography (HPTLC) with glycyrrhizin, 6,7-dimethoxycoumarin or poncirin for quantitative or qualitative analysis. Results: There were no gross changes in HPTLC-based compositional band-patterns of the three herbal mixture according to the storage conditions and period. The major components of each herb, glycyrrhizin, 6,7-dimethoxycoumarin and poncirin, showed slight time-dependent reduction in their contents both at room and cold temperature for 8 weeks. Conclusion: We could conclude that the current herbal decoction is generally safe for the stability at both RT or CT for at least 8 weeks. Nevertheless, we proposed that further advanced studies are required for more multiple herbal mixtures and longer storage periods.

• Mass Spectrometry Letters
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• v.6 no.2
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• pp.48-51
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• 2015

Kinsenoside is a principle bioactive compound of Anoectochilus formosanus. It exhibits various pharmacological effects such as antihyperglycemic, antioxidant, anti-inflammatory, immunostimulating, and hepatoprotective activities and has recently been developed as an antidiabetic drug candidate. In this study, as part of an in vitro pharmacokinetic study, the stability of kinsenoside in rat and human liver microsomes was evaluated. Kinsenoside was found to have good metabolic stability in both rat and human liver microsomes. These results will provide useful information for further in vivo pharmacokinetic and metabolism studies.

• Journal of mucopolysaccharidosis and rare diseases
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• v.1 no.1
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• pp.28-30
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• 2015

Biologics present a challenge to both the manufacturer and end user. They must usually be formulated as parenterals. However, they are often unstable in liquid form, due to their complex structure and composition. In that case, they must be manufactured using highly specialized processes, such as lyophilization (freeze-drying). Lyophilization nearly eliminates stability issues. Reducing a compound's sensitivity to temperature prolongs its shelf life. However, reconstitution can be cumbersome, involving multiple steps that increase the potential for error. Dual-chamber technology provides an effective alternative, combining a lyophilized drug and diluent in a closed system and enabling reconstitution in a few simple steps.

• Journal of Pharmaceutical Investigation
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• v.38 no.3
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• pp.157-162
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• 2008

The aim of the study was to formulate the stable amlodipine maleate tablet by selecting and combining of suitable ingredients. Amlodipine tablets were designed by using different manufacturing methods or formulations. Dissolution rate at 30 min of newly formulated tablets was over 98% in 0.1 M HCl medium. After 4 months storage under accelerated condition, the changes of appearance, loss on drying, content and total impurity were investigated. For long-term stability tests, two formulations of K017 (direct compressed tablets consisting of microcrystalline cellulose and pregelatinized starch) and K018 (wet granulated tablets by OpadryAMB) were stored under $25^{\circ}C$, 60% RH for 24 months. Under the accelerated condition, moisture content in K017 formulation was increased as 5.96% for 4 months, while other formulations with anhydrous monobasic phosphoric potassium or by wet granulation showed higher increase in moisture content compared to K017. In addition, K017 formulation showed a low decrease in contents and total relative substance as 0.8% and 0.7%, respectively. Similar stability of amlodipine in K017 was obtained under the long-term stability test. These results indicate that the K017 combined with microcrystalline cellulose and pregelatinized starch as ingredients is very stable formulation to protect active substance from moisture contact and sustain stability. Therefore, suitable combination of ingredients such as microcrystalline cellulose and pregelatinized starch could attribute to enhance the stability of moisture-labile drug such as amlodipine maleate.