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Seongnam, South Korea

Ryu S.H.,Dankook University | Ryu S.H.,GL PharmTech Corporation | Kim Y.S.,Korea Ginseng Corporation | Kim Y.S.,Toxicity Research Team | And 2 more authors.
Journal of Toxicology and Environmental Health - Part A: Current Issues

Red ginseng (RG) is one of the top selling herbal medicines in Korea, but is not recommended in hypertensive patients. In this study, the pharmacokinetic (PK) interaction between RG and losartan, an antihypertensive drug, was examined. RG was orally administered for 2 wk to male Sprague-Dawley (S-D) rats at either control (0), 0.5, 1, or 2 g/kg/d for 2 wk. After the last administration of RG and 30 min later, all animals were treated with 10 mg/kg losartan by oral route. In addition, some S-D rats were administered RG orally for 21 d at 2 g/kg followed by losartan intravenously (iv) at 10 mg/kg/d. Post losartan administration, plasma samples were collected at 5, 15, and 30 min and 1, 1.5, 2, 3, 6, 12, and 24 h. Plasma concentrations of losartan and E-3174, the active metabolite of losartan, were analyzed by a high-pressure liquid chromatography-tandem mass spectrometer system (LC-MS/MS). Oral losartan administration showed dose-dependent pharmacokinetics (PK) increase with time to maximum plasma, but this was not significant between different groups. There was no significant change in tmax with E-3174 PK. With iv losartan, pharmacokinetics showed elevation of area under the plasma concentration-time curve from time zero extrapolated to infinitity. There was not a significant change in AUCinf with E-3174 PK. Therefore, RG appeared to interfere with biotransformation of losartan, as RG exerted no marked effect on E-3174 PK in S-D rats. Data demonstrated that oral or iv treatment with losartan in rats pretreated with RG for 2 wk showed that losartan PK was affected but E-3174 PK remained unchanged among different dose groups. These results suggested that RG induces negligible influence on losartan and E-3174 PK in rats. Copyright © Taylor & Francis Group, LLC. Source

Park J.S.,GL PharmTech Corporation | Park J.S.,Chung - Ang University | Shim J.Y.,GL PharmTech Corporation | Choi Y.W.,Chung - Ang University | Jeong S.H.,Pusan National University
Drug Development and Industrial Pharmacy

A novel three-layered tablet consisting of a water-soluble mid-layer and two barrier layers with swellable polymers was investigated to develop a preferable once-a-day formulation containing terazosin HCl as a hydrophilic model drug. When the tablet was exposed to a release medium, the medium quickly permeated to the mid-layer and the two barrier layers swelled surrounding the mid-layer rapidly. It facilitated the tablet to absorb a lot of water compared with monolithic matrix. Moreover, formation of a lot of pores in the tablet during dissolution could be observed, suggesting significant water absorption in the inner matrix and swollen polymers of the tablet. Barrier layers influenced drug release profiles significantly, potentially due to differences in viscosity after swelling that produce different diffusion coefficients and mechanical strength. The drug in the mid-layer showed the sigmoid type of release pattern because a period of time might be needed to release the drug from the mid-layer through the barrier layers, but the drug in barrier layers showed the typical release pattern of monolithic matrix. As the amount of water-soluble excipient in the mid-layer increased, the degree of swelling also increased, suggesting that its amount in the layer may affect the overall swelling properties of the tablet. It was also shown that more hydrophilic mid-layer caused faster erosion rate, which was related to the results of swelling property. The three-layered tablets showed more consistent release kinetics than the matrix tablets. These results can give good information for the development of sustained drug delivery systems, especially once-a-day administration. © 2011 Informa Healthcare USA, Inc. Source

Park J.S.,GL PharmTech Corporation | Park J.S.,Chung - Ang University | Shim J.Y.,GL PharmTech Corporation | Lee M.J.,GL PharmTech Corporation | And 5 more authors.
Chemical and Pharmaceutical Bulletin

In order to develop a preferable once-a-day oral tablet formulation, various formulations of three-layered tablets containing tamsulosin HCl as a hydrophilic model drug were evaluated and compared with a commercial reference, tamsulosin OCAS® . When the test tablet was exposed to a release medium, the medium quickly permeated to the mid-layer and the two barrier layers swelled surrounding the mid-layer rapidly. Volume expansion showed faster and enough swelling of the three-layered tablet up to 2 h. Larger amount of barrier layers caused reduced release kinetics and a high molecular weight polymer showed more resistance against agitation force. A formulation with water-soluble mid-layer showed fast erosion decreasing its volume significantly. On the pharmacokinetic study, the mean ratio of area under the curve (AUC) and Cmax for the test formulation to the reference was 0.69 and 0.84, respectively, showing that the absorption of the drug was less complete than the reference. Plasma concentration at 24 h of the test formulation was higher than the reference. The Wagner-Nelson method showed that decreased initial dissolution rate might be the cause of the less complete absorption. On considering in vitro-in vivo correlation (IVIVC), level A, the reference (R2=0.981) showed more linear relationship than the test (R2=0.918) due to the decreased dissolution and absorption rate of the formulation. This result suggests that the in vitro dissolution profiles and release kinetics might be useful in correlating absorption kinetics as well as overall plasma drug concentration-time profiles for formulation studies. © 2011 Pharmaceutical Society of Japan. Source

Kwon M.,GL PharmTech Corporation | Kwon M.,Sungkyunkwan University | Yeom D.,GL PharmTech Corporation | Kim N.A.,Dongguk University | And 5 more authors.
Archives of Pharmacal Research

This study was to evaluate the pharmacokinetics and bioequivalence of two tacrolimus formulations which had different in vitro drug release profiles. Dynamic solubility, in vitro dissolution profiles of the two formulations, and their influence on pharmacokinetics were examined. The male volunteers were randomly assigned to receive a single 1-mg capsule of the test or reference formulation and pharmacokinetic parameters were determined using a noncompartmental method. The two formulations released >85 % of tacrolimus in water within 30 min, which passed the criterion of evaluating the test formulation. However, the test formulation produced a faster initial release rate and plateaued in about 15 min, while the reference showed almost zero order initial release profiles. The AUC0-∞ values were 145.92 (reference) and 140.49 ng h/mL (test). The mean Cmax was 15.70 (reference) and 16.08 ng/mL (test) with Tmax values of 1.63 and 1.60 h, respectively. The t1/2 for the reference and test formulations was 29.12 and 27.85 h, respectively. Relative bioavailability was calculated to be 96.28 %. The point estimates for the mean ratio of the test to reference for the AUC0-t and Cmax were 0.969 and 1.026, respectively, satisfying the criterion for bioequivalence. The results suggest that the test formulation is pharmacokinetically equivalent to the reference in terms of both rate and extent of absorption. Even though the in vitro dissolution profiles of the formulations might not be equivalent, the pharmacokinetics indicated bioequivalence. Therefore, when developing poorly soluble drugs, it might be beneficial to pay attention to the dynamic solubility as well as dissolution profiles. © 2014 The Pharmaceutical Society of Korea. Source

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