• Journal of the Korean Applied Science and Technology
• /
• v.32 no.2
• /
• pp.202-214
• /
• 2015

Stimuli-responsive biomaterials that alter their function through sensing local molecular cues may enable technological advances in the fields of drug delivery, gene delivery, actuators, biosensors, and tissue engineering. In this research, pH-responsive hydrogel which is comprised of dimethylaminoethyl methacylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) was synthesized for the effective delivery of doxorubicin (Dox) to breast cancer cells. Cancer and tumor tissues show a lower extracellular pH than normal tissues. DMAEMA/HEMA hydrogels showed significant sensitivity by small pH changes and each formulation of hydrogels was examined by scanning electron microscopy, mechanical test, equilibrium mass swelling, controlled Dox release, and cytotoxicity. High swelling ratios and Dox release were obtained at low pH buffer condition, low cross-linker concentration, and high content of DMAEMA. Dox release was accelerated to 67.3% at pH 5.5 for 6-h incubation at $37^{\circ}C$, while it was limited to 13.8% at pH7.4 at the same time and temperature. Cell toxicity results to breast cancer cells indicate that pH-responsive DMAEMA/HEMA hydrogels may be used as an efficient matrix for anti-cancer drug delivery with various transporting manners. Also, pH-responsive DMAEMA/HEMA hydrogels may be useful in therapeutic treatment which is required a triggered release at low pH range such as gene delivery, ischemia, and diabetic ketoacidosis.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.5
• /
• pp.761-764
• /
• 2002

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.12 s.189
• /
• pp.21-29
• /
• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.11a
• /
• pp.447-448
• /
• 2010

• Proceedings of the PSK Conference
• /
• 2003.10a
• /
• pp.47-49
• /
• 2003

Development of drug delivery systems has been recognized as one of portfolios to gain a competitive edge in pharmaceutical industry over 30 years. The application of drug delivery technologies offers pharmaceutical companies and patients several therapeutic benefits, including improving efficacy and adverse effect profiles, enhancing patient compliance and potentially regenerating unsuccessful drugs. (omitted)

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.54-55
• /
• 2006

Polymeric micelles, supramolecular assemblies of block copolymers, are useful nanocarriers for the systemic delivery of drugs and genes. Recently, novel polymeric micelles with various functions such as the targetability and stimuli-sensitivity have been emerged as promising carriers that enhance the efficacy of drugs and genes with minimal side effects. This presentation focuses our recent approach to the preparation of functional block copolymers that are useful for constructing smart micellar delivery systems in advanced therapeutics, including chemo-gene therapy. Particular emphasis is placed on the characteristic behaviors of intracellular environment-sensitive micelles that selectively exert drug activity and gene expression in live cells.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.236.1-236.1
• /
• 2002

Mucosal administration of drug or therapeutic gene is emerging as a new route of delivery for systemic and local therapeutics. Previously. in situ gelling system has been applied to chemical drug such as acetaminophen. insulin. prostaglandin E1. and clotrimazole. Plasmid DNA has not been delivered in form of in situ gelling vehicles. To improve the intranasal absorption of plasmid DNA. we designed delivery systems composed of provide of in 냐셔 gelling and mucoadhesive polymers. (omitted)

• Fisheries and Aquatic Sciences
• /
• v.18 no.1
• /
• pp.89-98
• /
• 2015

A synthesis method for a chitosan-coated magnetic drug-delivery system of cisplatin is proposed. Here, cisplatin was conjugated to the surface of Magnetite ($Fe_3O_4$) nanoparticles via a (3-Aminopropyl)-trimethoxysilane (APTS) coupling agent. To reduce the cytotoxic effect of cisplatin, the magnetic drug was then encapsulated in chitosan (CS-cisplatin-$Fe_3O_4$) through the water/oil (W/O) emulsion method. The CS-cisplatin-$Fe_3O_4$ nanoparticles were synthesized in a spherical shape with a diameter of 190 nm. The cytotoxicity assay was performed using HeLa cells. The cisplatin uptake of the cells was determined using High Performance Liquid Chromatography (HPLC) to calculate the drug content. The controlled release of cisplatin was demonstrated by regulating the dissolution and diffusion of the drug through the chitosan matrix.

• Journal of the Korean Society of Visualization
• /
• v.10 no.2
• /
• pp.32-38
• /
• 2012

In recent years a unique drug delivery system named as the transdermal drug delivery system has been developed which can deliver drug particles to the human skin without using any external needle. The solid drug particles are accelerated by means of high speed gas flow through a shock tube imparting enough momentum so that particles can penetrate through the outer layer of the skin. Different systems have been tried and tested in order to make it more convenient for clinical use. One of them is the contoured shock tube system (CST). The contoured shock tube consists of a classical shock tube connected with a correctly expanded supersonic nozzle. A set of bursting membrane are placed upstream of the nozzle section which retains the drug particle as well as initiates the gas flow (act as a diaphragm in a shock tube). The key feature of the CST system is it can deliver particles with a controllable velocity and spatial distribution. The flow dynamics of the contoured shock tube is analyzed numerically using computational fluid dynamics (CFD). To validate the numerical approach pressure histories in different sections on the CST are compared with the experimental results. The key features of the flow field have been studied and analyzed in details. To investigate the performance of the CST system flow behavior through the shock tube under different operating conditions are also observed.

• Archives of Pharmacal Research
• /
• v.13 no.2
• /
• pp.151-160
• /
• 1990

In order to develop a controlled-release oral drug delivery system (DDS) which sustains the plasma acetaminophen (AAP) concentration for a certain period of time, microporous membrane-coated tablets were prepared and evaluated in vitro. Firstly, highly water-soluble core tablet of AAP were prepared with various formulations by wet granulation and compression technique. Then the core tablets were coated with polyvinychloride (PVC) in which micronized sucrose particles were dispersed. Effect of formula compositions of core tablets and coating suspensions on the pharmaceutical characteristics such as drug release kinetics and membrane stability of the coated tablets was investigated in vitro. AAP was released from the coated tablets as a zero-order rate in a pH-independent manner. This independency of AAP release to pH change from 1.2 to 7.2 is favorable for the controlled oral drug delivery, since it will produce a constant drug release in the stomach and intestine regardless of the pH change in the GI tract. Drug release could be extended upto 10 h according to the coating condition. The release rate could be controlled by changing the formula compositions of the core tablets and coating suspensions, coat weight per each tablet, and especially PVC/sucrose ratio and particle size of the sucrose in the coating suspension. The coated tablets prepared in this study had a fairly good pharmaceutical characteristics in vitro, however, overall evaluation of the coated tablet should await in vivo absorption study in man.