Sang-Cheol Chi
Sungkyunkwan University
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Featured researches published by Sang-Cheol Chi.
International Journal of Pharmaceutics | 2001
Yun-Seok Rhee; Jung-Gyo Choi; Eun-Seok Park; Sang-Cheol Chi
A transdermal preparation containing ketoprofen was developed using O/W microemulsion system. Of the oils tested, oleic acid was chosen as the oil phase of the microemulsion, as it showed a good solubilizing capacity and excellent skin permeation rate of the drug. Pseudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant and cosurfactant for microemulsion formation, and the effect of these additives on skin permeation of ketoprofen was evaluated with excised rat skins. The optimum formulation of the microemulsion consisted of 3% ketoprofen, 6% oleic acid, 30% Labrasol/Cremophor RH 40 (1:1) and water. Terpenes were added to the microemulsion at the level of 5% and their effect on the skin permeation of ketoprofen from the microemulsion was evaluated. Of the four terpenes used, only limonene resulted in a powerful enhancing activity (3-fold increase over control).
Drug Development and Industrial Pharmacy | 2000
Ho-Jin Kim; Kyung Ae Yoon; Mikyoung Hahn; Eun-Seok Park; Sang-Cheol Chi
A new self-microemulsifying drug delivery system (SMEDDS) was developed to increase the dissolution rate, solubility, and, ultimately, bioavailability of a poorly water soluble drug, idebenone. Pseudoternary phase diagrams were used to evaluate the self-microemulsification existence area, and the release rate of idebenone was investigated. The mixtures consisting of Labrafac hydro or Labrafil 2609 (HLB values > 4) with the surfactant (Labrasol containing 80% Transcutol) and cosurfactant (Plurol oleique WL 1173) were found to be optimum formulations. Using the SMEDDS formulations of 5% to 20% of Labrafac hydro or Labrafil 2609 in combination with the surfactant/cosurfactant mixing ratio of 3, the microemulsion existence field was wider compared to the other SMEDDS formulations due to high affinity for the continuous phase. The in vitro dissolution rate of idebenone from SMEDDS was more than twofold faster compared with that of tablets. The developed SMEDDS formulation can be used as a possible alternative to traditional oral formulations of idebenone to improve its bioavailability.
International Journal of Pharmaceutics | 2000
Eun-Seok Park; Si-Young Chang; Mikyoung Hahn; Sang-Cheol Chi
The influence of polyethoxylated non-ionic surfactants on the transport of ibuprofen across rat skin was investigated. The skin permeation of ibuprofen from a series of 17 polyoxyethylene (POE) alkyl ethers containing 5% ibuprofen was determined using Franz diffusion cells fitted with excised rat skins. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were performed for the physicochemical characterization of ibuprofen-surfactant interaction. In vitro transdermal flux through excised rat skin was found in the decreasing order of POE(5)cetyl/oleyl ether (110.24 microg/cm(2)/h)>POE(2)lauryl ether (99.91 microg/cm(2)/h)>POE(2)oleyl ether (67.46 microg/cm(2)/h)>POE(10)stearyl ether (66.19 microg/cm(2)/h). POE(2)oleyl ether showed the longest lag time (2.47 h). The enhancers containing the EO chain length of 2-5, HLB value of 7-9 and an alkyl chain length of C16-C18 were effective promoters of ibuprofen flux. FT-IR and DSC studies to probe the nature of the interaction between the ibuprofen and surfactant indicated that the hydrogen bonding state of ibuprofen was changed from the dimeric form to the carbonyl-hydroxyl (C=O-HO) hydrogen bond form in the presence of excess POE alkyl ether. These results indicated that this new system may be used in developing a transdermal formulation with improved skin permeation of ibuprofen.
Archives of Pharmacal Research | 2007
Jong Soo Woo; Tae-Seo Kim; Jae Hyun Park; Sang-Cheol Chi
Silymarin has been used to treat hepatobiliary diseases. However, it has a low bioavailability after being administered orally on account of its low solubility in water. In order to improve the dissolution rate, silymarin was formulated in the form of a self-microemulsifying drug delivery system (SMEDDS). The optimum formulation of SMEDDS containing silymarin was obtained based on the study of pseudo-ternary phase diagram. The SMEDDS consisted of 15% silymarin, 10% glyceryl monooleate as the oil phase, a mixture of polysorbate 20 and HCO-50 (1:1) as the surfactant, Transcutol as the cosurfactant with a surfactant/cosurfactant ratio of 1. The mean droplet size of the oil phase in the microemulsion formed from the SMEDDS was 67 nm. The % release of silybin from the SMEDDS after 6 hours was 2.5 times higher than that from the reference capsule. After its oral administration to rats, the bioavailability of the drug from the SMEDDS was 3.6 times higher than the reference capsule.
International Journal of Pharmaceutics | 1993
Chong Kook Kim; Jung-Ju Kim; Sang-Cheol Chi; Chang-Koo Shim
Abstract The effects of several fatty acids and urea on the penetration of ketoprofen in propylene glycol and aqueous vehicles through excised rat skins have been studied. The penetration of ketoprofen through the skins increased 8–50-fold maximum compared to the control with the addition of the fatty acids in PG and urea in water. The enhancement of skin permeability of ketoprofen with the fatty acids in propylene glycol was mainly due to the increase in ketoprofen partitioning between the skin and the vehicle. When the concentration of lauric acid in propylene glycol — responsible for maximum permeation of ketoprofen — was varied from 0 to 10% in propylene glycol, ketoprofen permeation reached maximum with 5% lauric acid. The enhancement effect of urea on the penetration of ketoprofen through excised rat skins depended on the vehicles used. Its permeation constant increased significantly when added to ketoprofen-water vehicle. On the other hand, the effect of urea was not pronounced when added to ketoprofen-PG vehicle and ketoprofen-PG: ethanol: water (1:3:6) mixture. Nevertheless, the diffusion of ketoprofen through the skin increased in all three cases. Urea seemed to form large and extensive hydrophilic diffusion channels that do not exist in fresh skin.
International Journal of Pharmaceutics | 1995
Sang-Cheol Chi; Eun-Seok Park; Hyun Sil Kim
Abstract To increase the skin permeation rate of flurbiprofen, fatty acids and urea were added in propylene glycol vehicle containing 1% flurbiprofen. The enhancing effects of these compounds on the skin permeation of flurbiprofen were evaluated using Keshary-Chien diffusion cells fitted with excised rat skins. Unsaturated fatty acids increased the skin permeation rate of flurbiprofen 6.5–17.5 fold compared to the control vehicle without enhancer, while saturated fatty acids did not show any significant increase. Although the addition of urea in the vehicle decreased the skin permeation rate of flurbiprofen, the mixture of oleic acid and urea showed a significantly higher permeation rate than oleic acid alone. It was coincident with the results obtained with the plasma concentrations of flurbiprofen determined after the transdermal application of propylene glycol vehicle containing them. AUC and Cmax, x of the vehicle containing the mixture were increased 2.3 and 2.5 fold, respectively, whereas each parameter of the vehicle containing oleic acid only was increased 1.7 fold compared to those of the control vehicle.
Archives of Pharmacal Research | 2004
Jang-Hoon Kweon; Sang-Cheol Chi; Eun-Seok Park
A transdermal preparation containing diclofenac diethylammonium (DDA) was developed using an O/W microemulsion system. Of the oils tested, lauryl alcohol was chosen as the oil phase of the microemulsion, as it showed a good solubilizing capacity and excellent skin permeation rate of the drug. Pseudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant and cosurfactant for microemulsion formation, and the effect of these additives on skin permeation of DDA was evaluated with excised rat skins. The optimum formulation of the microemulsion consisted of 1.16% of DDA, 5% of lauryl alcohol, 60% of water in combination with the 34.54% of Labrasol (surfactant)/ethanol (cosurfactant) (1:2). The efficiency of formulation in the percutaneous absorption of DDA was dependent upon the contents of water and lauryl alcohol as well as Labrasol:ethanol mixing ratio. It was concluded that the percutaneous absorption of DDA from microemulsions was enhanced with increasing the lauryl alcohol and water contents, and with decreasing the Labrasol:ethanol mixing ratio in the formulation.
International Journal of Pharmaceutics | 2013
Nirmal Marasini; Tuan Hiep Tran; Bijay Kumar Poudel; Hyuk Jun Cho; Young Keun Choi; Sang-Cheol Chi; Han-Gon Choi; Chul Soon Yong; Jong Oh Kim
The present study was undertaken to overcome the problems associated with solubility, dissolution and oral bioavailability of a poorly water-soluble ionizable drug, telmisartan (TMS). For these purposes, a solubility test was carried to select the appropriate formulation composition from various carriers and alkalizers. Solid dispersions (SDs) of TMS were prepared at different drug-to-carrier ratios by the spray-drying technique, and were characterized by dissolution and aqueous solubility studies. The optimum formulation was investigated by dissolution studies at different pH and water media and its solid state characterisations were performed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. In solubility and dissolution tests, all TMS-loaded pH-modulated SDs (pH(M)-SDs) exhibited marked improvement in the dissolution behavior when compared with crystalline TMS powder. The optimum formulation of pH(M)-SD consisted of TMS/PVP (polyvinylpyrrolidone) K30/Na(2)CO(3) at a weight ratio of 2/0.5/3 and showed significant improvement in the aqueous solubility and dissolution rate by approximately 40,000- and 3-fold, respectively, compared to TMS powder. Solid-state characterization revealed the changed in crystallinity of TMS into amorphous state. Furthermore, area under the drug concentration time-curve (AUC) of TMS from the pH(M)-SD increased by 13.4- and 2.1-fold, compared with TMS powder and commercial product, respectively. According to these observations, taken together with dissolution and pharmacokinetic behaviors, pH-modulated SD in the presence of an alkalizer for a poorly water-soluble ionizable drug, TMS, appeared to be efficacious for enhancing its bioavailability.
International Journal of Pharmaceutics | 2013
Tuan Hiep Tran; Bijay Kumar Poudel; Nirmal Marasini; Sang-Cheol Chi; Han-Gon Choi; Chul Soon Yong; Jong Oh Kim
The aim of this study was to improve the physicochemical properties and bioavailability of a poorly water-soluble drug, raloxifene by solid dispersion (SD) nanoparticles using the spray-drying technique. These spray-dried SD nanoparticles were prepared with raloxifene (RXF), polyvinylpyrrolidone (PVP) and Tween 20 in water. Reconstitution of optimized RXF-loaded SD nanoparticles in pH 1.2 medium showed a mean particle size of approximately 180 nm. X-ray diffraction and differential scanning calorimetry indicated that RXF existed in an amorphous form within spray-dried nanoparticles. The optimized formulation showed an enhanced dissolution rate of RXF at pH 1.2, 4.0, 6.8 and distilled water as compared to pure RXF powder. The improved dissolution of raloxifene from spray-dried SD nanoparticles appeared to be well correlated with enhanced oral bioavailability of raloxifene in rats. Furthermore, the pharmacokinetic parameters of the spray-dried SD nanoparticles showed increased AUC(0-∞) and C(max) of RXF by approximately 3.3-fold and 2.3-fold, respectively. These results suggest that the preparation of RXF-SD nanoparticles using the spray drying technique without organic solvents might be a promising approach for improving the oral bioavailability of RXF.
International Journal of Pharmaceutics | 2008
Yun-Seok Rhee; Si-Young Chang; Chun-Woong Park; Sang-Cheol Chi; Eun-Seok Park
The aims of this study were to develop a transdermal gel formulation for ibuprofen using experimental design techniques and to evaluate its pharmacokinetic properties. The three factors chosen for factorial design were the concentrations of drug, polyoxyethylene(5)cetyl/oleyl ether and ethanol and the levels of each factor were low, medium and high. Skin permeation rates and lag times of ibuprofen were evaluated using the Franz-type diffusion cell in order to optimize the gel formulation. The permeation rate of ibuprofen significantly increased in proportion to the drug concentration, but significantly decreased in proportion to POE(5)cetyl/oleyl ether concentration. Ethanol concentration was inversely proportional to the lag time. The pharmacokinetic properties of the optimized formulation were compared with those of two marketed products in rats. The relative bioavailability of ibuprofen gel compared to the two marketed products was 228.8% and 181.0%. In conclusion, a transdermal ibuprofen gel was formulated successfully using the technique of experimental design and these results helped in finding the optimum formulation for transdermal drug release.