1.Effects of Fimasartan/Amlodipine Fixed-Dose Combination on Left Ventricular Systolic Function and Infarct Size in Rat Myocardial Infarction Model
Han Byul KIM ; Young Joon HONG ; Hyuk Jin PARK ; Youngkeun AHN ; Myung Ho JEONG
Chonnam Medical Journal 2019;55(3):144-149
		                        		
		                        			
		                        			The aim of this study was to evaluate the effects of fimasartan/amlodipine fixed-dosed combination (F/A) on left ventricle (LV) systolic function and infarct size in the rat myocardial infarction (MI) model. We induced MI in 20 rats by ligation of the left anterior descending coronary artery and they were divided into two groups [MI group (n=10) vs. MI+F/A 10 mg/kg group (n=10)]. F/A was administered for 28 days between day-7 and day-35 in the MI+F/A group and echocardiography was performed at day-7 and at day-35 after the induction of MI. Picrosirius red staining was performed to confirm the fibrotic tissue and infarct size was measured using image analysis program for Image J. At the 35-day follow-up, the LV ejection fraction (EF) was significantly higher (38.10±3.92% vs. 29.86±4.56%, p<0.001) and delta (day-35 minus day-7) EF was significantly higher (0.14±2.66% vs. −8.53±2.66%. p<0.001) in the MI+F/A group than the MI group. Systolic blood pressure was significantly lower in the MI+F/A group than the MI group (103.23±13.35 mmHg vs. 123.43±14.82 mmHg, p<0.01). The MI+F/A group had a smaller infarct size (26.84±5.31% vs. 36.79±3.10%, p<0.01) than the MI group at the 35-day follow-up. Oral administration of F/A 10 mg/kg could improve LV systolic function and reduce infarct size in a rat MI model.
		                        		
		                        		
		                        		
		                        			Administration, Oral
		                        			;
		                        		
		                        			Angiotensin Receptor Antagonists
		                        			;
		                        		
		                        			Animals
		                        			;
		                        		
		                        			Blood Pressure
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		                        			Calcium Channel Blockers
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		                        			Coronary Vessels
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		                        			Echocardiography
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		                        			Follow-Up Studies
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		                        			Heart Ventricles
		                        			;
		                        		
		                        			Ligation
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		                        			Myocardial Infarction
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		                        			Rats
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		                        			Ventricular Remodeling
		                        			
		                        		
		                        	
2.Clinical Study of Acute Vasoreactivity Testing in Patients with Chronic Thromboembolic Pulmonary Hypertension.
Qi-Xia XU ; ; Yuan-Hua YANG ; Jie GENG ; Zhen-Guo ZHAI ; Juan-Ni GONG ; Ji-Feng LI ; Xiao TANG ; Chen WANG ;
Chinese Medical Journal 2017;130(4):382-391
BACKGROUNDThe clinical significance of acute vasoreactivity testing (AVT) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) remains unclear. We analyzed changes in hemodynamics and oxygenation dynamics indices after AVT in patients with CTEPH using patients with pulmonary arterial hypertension (PAH) as controls.
METHODSWe analyzed retrospectively the results of AVT in 80 patients with PAH and 175 patients with CTEPH registered in the research database of Beijing Chao-Yang Hospital between October 2005 and August 2014. Demographic variables, cardiopulmonary indicators, and laboratory findings were compared in these two subgroups. A long-term follow-up was conducted in patients with CTEPH. Between-group comparisons were performed using the independent-sample t-test or the rank sum test, within-group comparisons were conducted using the paired t-test or the Wilcoxon signed-rank test, and count data were analyzed using the Chi-squared test. Survival was estimated using the Kaplan-Meier method and log-rank test.
RESULTSThe rates of positive response to AVT were similar in the CTEPH (25/175, 14.3%) and PAH (9/80, 11.3%) groups (P > 0.05). Factors significantly associated a positive response to AVT in the CTEPH group were level of N-terminal pro-brain natriuretic peptide (≤1131.000 ng/L), mean pulmonary arterial pressure (mPAP, ≤44.500 mmHg), pulmonary vascular resistance (PVR, ≤846.500 dyn·s-1·m-5), cardiac output (CO, ≥3.475 L/min), and mixed venous oxygen partial pressure (PvO2, ≥35.150 mmHg). Inhalation of iloprost resulted in similar changes in mean blood pressure, mPAP, PVR, systemic vascular resistance, CO, arterial oxygen saturation (SaO2), mixed venous oxygen saturation, partial pressure of oxygen in arterial blood (PaO2), PvO2, and intrapulmonary shunt (Qs/Qt) in the PAH and CTEPH groups (all P > 0.05). The survival time in patients with CTEPH with a negative response to AVT was somewhat shorter than that in AVT-responders although the difference was not statistically significant (χ2 =3.613, P = 0.057). The survival time of patients with CTEPH who received calcium channel blockers (CCBs) was longer than that in the group with only basic treatment and not shorter than that of patients who receiving targeted drugs or underwent pulmonary endarterectomy (PEA) although there was no significant difference between the four different treatment regimens (χ2 =3.069, P = 0.381).
CONCLUSIONSThe rates of positive response to AVT were similar in the CTEPH and PAH groups, and iloprost inhalation induced similar changes in hemodynamics and oxygenation dynamics indices. A positive response to AVT in the CTEPH group was significantly correlated with milder disease and better survival. Patients with CTEPH who cannot undergo PEA or receive targeted therapy but have a positive response to AVT might benefit from CCB treatment.
Administration, Inhalation ; Adult ; Aged ; Arterial Pressure ; drug effects ; Atrial Natriuretic Factor ; metabolism ; Calcium Channel Blockers ; administration & dosage ; therapeutic use ; Endarterectomy ; Familial Primary Pulmonary Hypertension ; drug therapy ; physiopathology ; Female ; Hemodynamics ; drug effects ; Humans ; Hypertension, Pulmonary ; drug therapy ; physiopathology ; Iloprost ; administration & dosage ; therapeutic use ; Male ; Middle Aged ; Protein Precursors ; metabolism ; Retrospective Studies ; Software ; Vasodilator Agents ; administration & dosage ; therapeutic use
3.Efficacy and safety of the treatment: combination of benazepril/lercanidipine vs. benazepril alone in patients with mild-to-moderate hypertension.
Ting CHEN ; Guang-Hui CHEN ; Ting-Shu YANG ; Zhen-Yu ZHONG ; Wei-Shuai AN ; Xiao-Xia ZHANG ; Jia-Dan LI
Chinese Medical Journal 2013;126(12):2286-2290
BACKGROUNDCombination therapy is an effective method to reduce the blood pressure (BP) for patients with hypertension. This study was performed to evaluate the efficacy and safety of benazepril/lercanidipine compared with benazepril alone in patients with mild-to-moderate hypertension.
METHODSOne hundred and eighty-one patients with mild-to-moderate primary hypertension were assigned in this randomized, single-blind, parallel-group study and were randomly divided into group A (benazepril 10 mg/lercanidipine 10 mg) and group B (benazepril 10 mg) for 8 weeks. At 4 weeks, the dosage of Benazepril was titrated up to 20 mg if the diastolic blood pressure (DBP) remained ≥ 90 mmHg. BP control and side effects were evaluated at the end of 1, 4 and 8 weeks.
RESULTSThe baseline characteristics of the two groups were similar. The BP in both groups decreased from the baseline (P < 0.05). At the end of 4 and 8 weeks, Benazepril/Lercanidipine produced greater BP reduction than Benazepril alone (P < 0.05). The comparison of the rate of BP control for the benazepril/lercanidipine and benazepril groups at the end of 1, 4, and 8 weeks were 41.2% vs. 37.6% (P > 0.05), 67.1% vs. 44.7% (P < 0.05), and 71.8% vs. 45.9% (P < 0.05). There was no significant difference of side effects between the two groups.
CONCLUSIONThe benazepril/lercanidipine combination is more effective in reducing BP than benazepril alone, while it does not increase the incidence of side effects.
Aged ; Angiotensin-Converting Enzyme Inhibitors ; therapeutic use ; Benzazepines ; administration & dosage ; adverse effects ; therapeutic use ; Blood Pressure ; drug effects ; Calcium Channel Blockers ; administration & dosage ; Dihydropyridines ; administration & dosage ; adverse effects ; Drug Therapy, Combination ; Female ; Humans ; Hypertension ; drug therapy ; Male ; Middle Aged ; Single-Blind Method
4.Analysis and evaluation of the impurity of felodipine and its tablets.
Na ZHANG ; Li-Ju YU ; Jie LI ; Jun-Wei TONG ; Jie MENG ; Qi-Ming ZHANG ; Ya-Qin SHI
Acta Pharmaceutica Sinica 2012;47(2):223-228
		                        		
		                        			
		                        			The paper reports the systematic study on felodipine and its impurities in tablets, to improve its quality standards for the control of the related substances. HPLC-DAD, UPLC-MS, IR and NMR methods were used for the isolation of felodipine and its impurities in tablets, their identification and the zebrafish animal model was used for the analysis of the toxic impurities. In felodipine material and its tablets, three impurities are isolated and identified. They are impurity 1 [dimethyl 4-(2, 3-dichlorophenyl)-2, 6-dimethyl-1, 4-dihydropyridine-3, 5-dicarboxylate], impurity 2 [ethyl methyl 4-(2, 3-dichlorophenyl)-2, 6-dimethylpyridine-3, 5-dicarboxylate] and impurity 3 [diethyl 4-(2, 3-dichlorophenyl)-2, 6-dimethyl-1, 4-dihydropyridine-3, 5-dicarboxylate], separately. The result of zebrafish animal model analysis showed that the teratogenic effects of four compounds were: impurity 3 > or = felodipine > impurity 1 > impurity 2, lethal effects were as follows: impurity 2 = impurity 3 > felodipine > or = impurity 1. This study confirmed the toxicity of three impurities in felodipine. According to the results, the paper suggested the amendments to the standard of the medicine and provided the support to the control of impurities in the manufacturing process.
		                        		
		                        		
		                        		
		                        			Abnormalities, Drug-Induced
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		                        			Animals
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		                        			Antihypertensive Agents
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		                        			administration & dosage
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		                        			chemistry
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		                        			toxicity
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		                        			Calcium Channel Blockers
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		                        			administration & dosage
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		                        			chemistry
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		                        			toxicity
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		                        			Chromatography, High Pressure Liquid
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		                        			methods
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		                        			Drug Contamination
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		                        			Felodipine
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		                        			administration & dosage
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		                        			chemistry
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		                        			toxicity
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		                        			Magnetic Resonance Spectroscopy
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		                        			Molecular Structure
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		                        			Pharmaceutical Preparations
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		                        			analysis
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		                        			chemistry
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		                        			Quality Control
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		                        			Spectrophotometry, Infrared
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		                        			Tablets
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		                        			Tandem Mass Spectrometry
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		                        			Zebrafish
		                        			
		                        		
		                        	
5.A Case of Severe Coronary Spasm Associated with 5-Fluorouracil Chemotherapy.
Sang Min KIM ; Cheol Hoon KWAK ; Bora LEE ; Seong Beom KIM ; Jung Ju SIR ; Wook Hyun CHO ; Suk Koo CHOI
The Korean Journal of Internal Medicine 2012;27(3):342-345
		                        		
		                        			
		                        			Cardiotoxicity associated with 5-fluorouracil (FU) is an uncommon, but potentially lethal, condition. The case of an 83-year-old man with colon cancer who developed chest pain during 5-FU infusion is presented. The electrocardiogram (ECG) showed pronounced ST elevation in the lateral leads, and the chest pain was resolved after infusion of nitroglycerin. A coronary angiogram (CAG) revealed that the patient had significant atherosclerosis in the proximal left circumflex artery. Coronary artery spasm with fixed stenosis was considered, and a drug-eluting stent was implanted. After 8 hours, the patient complained of recurring chest pain, paralleled by ST elevation on the ECG. The chest pain subsided after administration of intravenous nitroglycerin followed by sublingual nifedipine. Repeated CAG showed patency of the previous stent. This case supports the vasospastic hypothesis of 5-FU cardiac toxicity, indicating that a calcium channel blocker may be effective in the prevention or treatment of 5-FU cardiotoxicity.
		                        		
		                        		
		                        		
		                        			Aged, 80 and over
		                        			;
		                        		
		                        			Angina Pectoris/chemically induced
		                        			;
		                        		
		                        			Antineoplastic Combined Chemotherapy Protocols/administration & dosage/*adverse effects
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		                        			Calcium Channel Blockers/administration & dosage
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		                        			Colonic Neoplasms/*drug therapy
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		                        			Coronary Angiography
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		                        			Coronary Vasospasm/*chemically induced/diagnosis/therapy
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		                        			Drug-Eluting Stents
		                        			;
		                        		
		                        			Electrocardiography
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		                        			Fluorouracil/administration & dosage/*adverse effects
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		                        			Humans
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		                        			Leucovorin/administration & dosage/adverse effects
		                        			;
		                        		
		                        			Male
		                        			;
		                        		
		                        			Nifedipine/administration & dosage
		                        			;
		                        		
		                        			Nitroglycerin/administration & dosage
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		                        			Organoplatinum Compounds/administration & dosage/adverse effects
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		                        			Percutaneous Coronary Intervention/instrumentation
		                        			;
		                        		
		                        			Recurrence
		                        			;
		                        		
		                        			Severity of Illness Index
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		                        			Treatment Outcome
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		                        			Vasodilator Agents/administration & dosage
		                        			
		                        		
		                        	
6.Limited sampling strategy models for estimating AUC for amlodipine in Chinese healthy volunteers.
Kun WANG ; Yu-cheng SHENG ; Ying-chun HE ; Juan YANG ; Mi ZHANG ; Ling XU ; Jin-min SHI ; Qing-shan ZHENG
Acta Pharmaceutica Sinica 2010;45(12):1582-1586
		                        		
		                        			
		                        			This study aims to save cost of sampling for estimating the area under the amlodipine plasma concentration versus time curve in 24 hours (AUC(0-24 h)). Limited sampling strategy (LSS) models was developed and validated by mutiple regression model within 4 or fewer amlodipine concentration values. Absolute prediction error (APE), root of mean square error (RMSE) and visual predict check were used as criterion. The results of Jackknife validation showed that fifteen (9.4%) of the 160 LSS based on regression analysis were not within an APE of 15% by using one concentration-time point. 156 (97.5%), 159 (99.4%) and 160 (100%) of the 160 LSS model were capable of predicting within an APE 15% by using 2, 3, 4 points, separately. Limited sampling strategies have been developed and validated for estimating AUC(0-24 h) of amlodipine. The present study indicated that the implemention of both 5 mg and 10 mg dosage could enable accurate predictions of AUC(0-24 h) by the same LSS model. This study shows that 12, 4, 24, 2 h after administration are key sampling time points. The combination of (12, 4), (12, 4, 24) or (12, 4, 24, 2 h) might be chosen as sampling hours for predicting AUC(0-24 h) in practical application according to requirement.
		                        		
		                        		
		                        		
		                        			Administration, Oral
		                        			;
		                        		
		                        			Adult
		                        			;
		                        		
		                        			Amlodipine
		                        			;
		                        		
		                        			administration & dosage
		                        			;
		                        		
		                        			blood
		                        			;
		                        		
		                        			pharmacokinetics
		                        			;
		                        		
		                        			Antihypertensive Agents
		                        			;
		                        		
		                        			administration & dosage
		                        			;
		                        		
		                        			blood
		                        			;
		                        		
		                        			pharmacokinetics
		                        			;
		                        		
		                        			Area Under Curve
		                        			;
		                        		
		                        			Asian Continental Ancestry Group
		                        			;
		                        		
		                        			Calcium Channel Blockers
		                        			;
		                        		
		                        			administration & dosage
		                        			;
		                        		
		                        			blood
		                        			;
		                        		
		                        			pharmacokinetics
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		                        			Humans
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		                        			Male
		                        			;
		                        		
		                        			Models, Biological
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		                        			Regression Analysis
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		                        			Sample Size
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		                        			Vasodilator Agents
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		                        			administration & dosage
		                        			;
		                        		
		                        			blood
		                        			;
		                        		
		                        			pharmacokinetics
		                        			;
		                        		
		                        			Young Adult
		                        			
		                        		
		                        	
7.Effects of Xuezhikang and pravastatin on circulating endothelial progenitor cells in patients with essential hypertension.
Li LU ; Jian-zhong ZHOU ; Li WANG ; Tie-xu ZHANG
Chinese journal of integrative medicine 2009;15(4):266-271
OBJECTIVETo investigate the impacts of Xuezhikang (XZK) or pravastatin combined with antihypertensive drugs on circulating endothelial progenitor cells (CEPCs) in essential hypertensive (EH) patients.
METHODSEighty-eight EH patients were enrolled into the study and randomly assigned to the antihypertensive drug treatment group (ATH group, 29 cases), the pravastatin treatment group (PRA group, 29 cases) and the Xuezhikang treatment group (XZK group, 30 cases). Patients in the 3 groups were treated with routine antihypertensive drugs. In addition, pravastatin and Xuezhikang were given to the patients in the PRA group and XZK group, respectively. After an eight-week treatment, CEPCs were counted using a laser scanning confocal microscope, and their proliferation function was evaluated by the MTT colorimetric assay and the adherent cell number was counted to estimate the adhesion function.
RESULTSAfter the treatment, CEPCs in the PRA group (116.60+/-5.70) and XZK group (114.40+/-6.55) was significantly higher than that in the ATH group (88.00+/-6.32, P<0.01). CEPCs proliferation capability and the adhesion function in the PRA group (0.406+/-0.016, 33.60+/-4.26) and XZK group (0.415+/-0.018, 34.30+/-3.77) were obviously superior to those in the ATH group (0.333+/-0.021, P<0.01; 23.30+/-3.19, P<0.01). No significant difference was found between the pravastatin group and the XZK group.
CONCLUSIONSCombined use of XZK or pravastatin with the anti-hypertensive therapy could increase the CEPCs number and improve their function in EH patients with the blood pressure controlled by antihypertensive drugs, leading to benefits independent of pressure-lowering effects.
Aged ; Anticholesteremic Agents ; administration & dosage ; Antidiuretic Agents ; administration & dosage ; Antihypertensive Agents ; administration & dosage ; Blood Cell Count ; Calcium Channel Blockers ; administration & dosage ; Cell Adhesion ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Drug Therapy, Combination ; Drugs, Chinese Herbal ; administration & dosage ; Endothelial Cells ; drug effects ; pathology ; physiology ; Female ; Humans ; Hypertension ; blood ; drug therapy ; pathology ; physiopathology ; Integrative Medicine ; methods ; Male ; Middle Aged ; Pravastatin ; administration & dosage ; Stem Cells ; drug effects ; pathology ; physiology
8.Roles of potassium channel in effects of resveratrol on isolated myocardial contractility and heart rate research in guinea pig.
Gui-ying WANG ; Cui-miao SONG ; Li-nan ZHANG ; Qian LI ; Hua YUE ; Jing-kun FENG ; Na WANG
China Journal of Chinese Materia Medica 2007;32(13):1317-1319
OBJECTIVETo study the effects of resvaratrol derivatives on spontaneous HR and CF of isolated guinea pig atrium.
METHODThe dose-effect curve of resvaratrol was observed. The possible mechanism of potassium channels responsible for changes of CF and HR after administering with resvaratrol was measured.
RESULTResvaratrol reduced the spontaneous HR and weakened the CF in a dose-dependent manner ranging from 10(-6) to 3 x 10(-4) mol x L(-1) (P < 0.05). As compared with Res group, the effects were partly blocked by Gli (P < 0.05) and TEA (P < 0.01), but not blocked by 4-AP, BaCl2, Atropine.
CONCLUSIONResvaratrol can induce negative chronotropic action and negative (inotropic action. The mechanism(s) may relate to the opening of K(ATP) and Kc(Ca).
Animals ; Barium Compounds ; pharmacology ; Cardiotonic Agents ; administration & dosage ; isolation & purification ; pharmacology ; Chlorides ; pharmacology ; Dose-Response Relationship, Drug ; Female ; Glyburide ; pharmacology ; Guinea Pigs ; Heart Rate ; drug effects ; In Vitro Techniques ; KATP Channels ; antagonists & inhibitors ; Male ; Myocardial Contraction ; drug effects ; Plants, Medicinal ; chemistry ; Potassium Channel Blockers ; pharmacology ; Potassium Channels, Calcium-Activated ; antagonists & inhibitors ; Potassium Channels, Inwardly Rectifying ; antagonists & inhibitors ; Stilbenes ; administration & dosage ; isolation & purification ; pharmacology ; Tetraethylammonium ; pharmacology
9.The effect of tetramethylpyrazine on the pharmacokinetics of intragastrically administered cyclosporine A in rats.
Xiao-lei LIU ; Jing TANG ; Juan SONG ; Juan HE ; Ping XU ; Wen-xing PENG
Acta Pharmaceutica Sinica 2006;41(9):882-887
AIMTo investigate the possible effect of tetramethylpyrazine (TMP), an active ingredient of a commonly used Chinese herb, on the pharmacokinetics of cyclosporine A (CsA) by intragastric administration in rats.
METHODSForty male Sprague-Dawley rats were equally divided into four groups by randomized block design according to weight. On the first day, after each fasting rat was intragastrically administered CsA (10 mg x kg(-1)), blood samples (0.2 - 0.25 mL) were collected from the tail vein at 0, 1, 2, 3, 4, 6, 8, 12, 24, 36 and 48 h. From day 4 to day 8, each group began to undergo different pretreatments with intragastric administration of water, verapamil (Ver), low and high dose TMP, separately. On day 9, each group intragastrically co-administered CsA (10 mg x kg(-1)) and different pretreatment compounds mentioned above, then blood samples were collected according to the schedule of the first day. The whole blood concentration of CsA was determined by HPLC. Main pharmacokinetic parameters were calculated and compared by statistic analysis.
RESULTSIn the group of water pretreated and co-administrated with CsA, no significantly different pharmacokinetic parameters of CsA were found. After Ver pretreatment and co-administration with CsA, AUC(0-48 h) and C(max) were increased significantly (P < 0.01 and P < 0.05); T(1/2) beta and CL were markedly prolonged and decreased (P < 0.05); T(max) and V were not apparently influenced. After low dose TMP pretreatment and co-administration with CsA, there was no significant difference in the pharmacokinetic parameters of CsA, in spite of the increasing trends of AUC(0-48 h) and C(max). After high dose TMP pretreatment and co-administration with CsA, AUC(0-48 h) and C(max) of CsA were increased significantly (P < 0.01), but there was no significant change in other parameters.
CONCLUSIONIt was indicated that the high dose of TMP could apparently increase the intragastric absorption extent of CsA, while almost had no effect on its elimination process.
Administration, Oral ; Animals ; Area Under Curve ; Biological Availability ; Calcium Channel Blockers ; pharmacology ; Cyclosporine ; administration & dosage ; blood ; pharmacokinetics ; Dose-Response Relationship, Drug ; Drug Administration Routes ; Immunosuppressive Agents ; administration & dosage ; blood ; pharmacokinetics ; Ligusticum ; chemistry ; Male ; Plants, Medicinal ; chemistry ; Pyrazines ; administration & dosage ; isolation & purification ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Stomach ; Verapamil ; pharmacology
10.Preparation of verapamil hydrochloride controlled-onset extended-release pellets and its pharmacokinetics in dogs.
Zhi-peng CHEN ; Yan-yu XIAO ; Hong-xuan CHEN ; Xi-jing CHEN ; La-rui LI ; Jia-bi ZHU
Acta Pharmaceutica Sinica 2006;41(8):765-771
AIMTo prepare verapamil hydrochloride controlled-onset extended-release pellets (VH-COERP) and study its release behavior in vitro. To compare the pharmacokinetic characteristics and bioavailability in six Beagle dogs after oral administration of VH-COERP and verapamil hydrochloride delayed-release pellets (VH-DRP) as reference.
METHODSThe core of VH-COERP were prepared in the fluidized bed (mini-glatt) by spraying water solution containing drugs onto sucrose-starch pellets with hydroroxy propyl methyl cellulose (HPMC) as the inner coating swelling layer and ethylcellulouse aqueous dispersion as the outer coating controlled layer. Through modifying the coating level of inner and outer layer, the VH-COERP with the optimized cumulative release profile was obtained. The concentration of VH in plasma of six dogs and its pharmacokinetic behaviors after oral administration of VH-COERP and VH-DRP at different times were studied by RP-HPLC. The pharmacokinetic parameters were computed by software program 3P97.
RESULTSThe lag time, the release behavior and the amount of VH from VH-COERP within 24 hours were not influenced by the pH of dissolution medium and post-process, but obviously influenced by the different kinds of added material in swelling layer and the coating level of the inner swelling layer and the outer controlled layer. In vitro the lag time of release profile of VH from VH-COERP was 5 h and then VH was extended release from VH-COERP in the following time. Compared with the VH-DRP, VH-COERP in vivo has an obviously lag time (4 h) , Tmax was also delayed (8 h) and the relative bioavailability was (94.56 +/- 7.64)%.
CONCLUSIONThe release profile of VH from VH-COERP was shown to be extended-release after an conspicuous lag time in vitro and in vivo. So the drug can be taken by the patient before bed time and begin to work at the morning.
Administration, Oral ; Animals ; Biological Availability ; Calcium Channel Blockers ; administration & dosage ; pharmacokinetics ; Cellulose ; analogs & derivatives ; chemistry ; Delayed-Action Preparations ; Dogs ; Drug Stability ; Hypromellose Derivatives ; Methylcellulose ; analogs & derivatives ; chemistry ; Microscopy, Electron, Scanning ; Verapamil ; administration & dosage ; chemistry ; pharmacokinetics
            
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