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RISS 인기검색어
- 검색키워드
- 저자 : Langchong He (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
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Pharmacokinetic Behavior and Tissue Distribution of Verapamil and Its Enantiomers in Rats by HPLC
He, Langchong,Wang, Sicen The Pharmaceutical Society of Korea 2003 Archives of Pharmacal Research Vol.26 No.9
The differences in pharmacokinetic behavior and tissue distribution of verapamil and its enantiomers were investigated in rats. In high-performance liquid chromatographic method, an achiral ODS column (150 mm $\times$ 4.6 mm i.d.) with the mobile phase consisting of methanol-water (73:30, v/v) was used for the determination of the concentration for racemic verapamil, and a Chiralcel OJ column (250 mm$\times$4.6 mm i.d.) with the mixture of n-haxane-ethanol-triethylamine (85:15:0.2, v/v/v) as mobile phase was used to determine the concentrations of verapamil enantiomers. A fluorescence detector in the analytical system was set at excitation and emission wavelengths of 275 nm and 315 nm. The differences between enantiomers were apparent in the pharmacokinetics in rats. The area under the concentration-time curve (AUC) of S-(-) verapamil was higher than that of R-(+) verapamil. The half-distribution time ($T_{1/2(\alpha)}$) of S-(-) verapamil which distributing to tissue from blood was shorter than that of R-(+) verapamil, but the elimination half-time ($T_{1/2(\beta)}$) was longer in rat following oral administration of racemic verapamil. At 1.3 h after oral administration of racemic verapamil, however, there were no significant differences between enantiomers for the distributions in major tissues such as heart, cerebrum, cerebellum, liver, spleen and kidney.
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Sicen Wang,Langchong He,Bofeng Yun 대한약학회 2005 Archives of Pharmacal Research Vol.28 No.3
The present study was designed to study the difference effects between nicardipine and its two enantiomers on thoracic artery of rabbit. A high-performance liquid chromatographic method was used to prepare the two enantiomers of nicardipine. The thoracic artery of rabbit was removed. The vessels were cut into 3 mm in width and 15 mm in length spiral strips and immersed into tissue baths. The concentration-response curves of nicardipine and its enantiomers were obtained by cumulative administration of the vasoconstrictors. Nicardipine and the enantiomers could shift the dose-response curves of NE, KCl or CaCl2 to right in a nonparallel manner and decrease the maximum effective in a concentration-depended manner, respectively. The pD2' value of R-(-)-nicardipine showed significantly effective than that of nicardipine and S-(+)-nicardipine (P<0.01). There was not obviouse difference between the pD2' value of nicardipine and S-(+)-nicardipine (P>0.05). The results demonstrate that the stereoselective interaction between R-(-)-nicardipine and L-calcium channel receptor is more stronger than that of S-(+)-nicardipine.
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Imperatorin Sustained-release Tablets: In Vitro and Pharmacokinetic Studies
Jingjing Pan,Wen Lu,Changhui Li,Sicen Wang,Langchong He 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.8
We prepared and evaluated imperatorin (IMP) sustained-release tablets. IMP is an active compound in Angelica dahuricae, a Chinese herbal medicine. We used different polymers, such as hydroxypropyl methylcellulose (HPMC K4M, K15M, and K100M), carbopol 934P, sodium carboxymethyl cellulose (CMC-Na), and their combinations to prepare the matrix tablets and achieve the desired sustained release profile. The in vitro release profiles of these formulations were examined and fit to various kinetic release models. We also tested the effects of polymer combination ratios on the in vitro release rate. In vivo studies were performed for the optimized formulation in six beagle dogs, and pharmacokinetic parameters were compared with plain IMP tablets. IMP sustained-release tablets exhibited a more sustained plasma concentration than the plain tablets, with a relative bioavailability of 127.25%. The in vitro releases rates and in vivo absorption correlated for the initial 8 hours. These results demonstrate that the sustained-release tablet system can effectively control the release of IMP.
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A Fluorenone Alkaloid from Caulophyllum robustum Maxim. with Anti-myocardial Ischemia Activity
Sicen Wang,Binyu Wen,Na Wang,Juntian Liu,Langchong He 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.4
A new fluorenone alkaloid (caulophine) was isolated from the radix of Caulophyllum robustumMaxim. (collected from the Qinling mountains) using cell membrane chromatography as the screening method. Caulophine was identified as 3-(2-(dimethylamino)ethyl)-4,5-dihydroxy-1,6-dimethoxy-9H-fluoren-9-one based on physicochemic and spectroscopic analyses, particularly by NMR spectroscopic data (i.e., COSY, HMQC, HMBC, NOESY). Caulophine possessed anti-myocardial ischemia activity.
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