Pharmacokinetic interaction between cefaclor and bromhexine in healthy Chinese volunteers.

OBJECTIVE: To determine the pharmacokinetic interaction between cefaclor and bromhexine in healthy Chinese volunteers. METHODS: Twelve subjects received a cefaclor (CEF) treatment, a bromhexine (BHX) treatment, and a co-treatment of CEF and BHX with a 3 x 3 Latin square design. The wash-out time between periods was 14 days. The plasma and urine drug concentrations of CEF and BHX were detected by HPLC-UV and LC/MS, respectively. RESULTS: All the 12 volunteers completed the study. There were no significant differences in AUC 0-t and Cmax of CEF in logarithm between the single administration group of CEF and the co-administration group of CEF with BHX. Two one sided t-test showed that CEF was bioequivalent in the 2 groups. There were no significant differences in tmax, MRT, t1/2, and Clr between the 2 groups. Vd/F was significantly lower in the single CEF group than in the co-administration group of CEF and BHX. There were no significant differences of AUC 0-t and Cmax of BHX in logarithm between the single administration group of BHX and the co-administration group of BHX with CEF. Two one sided t-test showed that BHX was bioequivalent in the 2 groups. There were no significant differences in tmax, MRT, t1/2, Vd/F, and Clr between the 2 groups. CONCLUSION: There is no significant pharmacokinetic parameter change in the drug absorption, metabolism, and excretion, but Vd/F of CEF significant increases in the co-administration of CEF with BHX. The co-administration of CEF and BHX has no adverse drug interaction. The increase of Vd/F may be a favorable drug interaction, which may be the mechanism of the synergistic effect of the 2 drugs.

[Pharmacokinetics of erythromycin stinoprate capsule].

OBJECTIVE: To determine the pharmacokinetics of erythromycin stinoprate capsules and to provide guidance for clinical research. METHODS: Thirty healthy volunteers (15 men and 15 women) were divided into 3 groups randomly, each including 5 men and 5 women. Single oral doses of 250, 500 and 750 mg were given to each volunteer. The concentrations of erythromycin propionate and erythromycin base in the plasma were determined by HPLC-MS. RESULTS: All 30 volunteers completed the experiment without adverse reactions. Using 3P87 we analyzed the model and calculated the pharmacokinetic parameters. Three dose groups taking high, middle and low dose were all single compartment model. The pharmacokinetic parameters of erythromycin propionate after taking erythromycin stinoprate capsules were as follows: Low dose group: Ka (2.007 +/- 1.281 )/h, tmax ( actual value) (1.9 +/- 0.6) h, Cmax (437.0 +/- 295.0) microg/L, AUC0-14 (trapezoid area) (1840.2 +/- 1476.87) microg x h/L, Ke (0.329 +/- 0.119)/h, T1/2 (2.45 +/- 0.9) h. Middle dose group: Ka (1.451 +/- 0.380)/h, tmax (1.7 +/- 0.3) h, Cmax (923.1 +/- 217.5) microg/L, AUC0-14 (4542.44 +/- 1579.4) microg x h/L,Ke (0.237 +/- 0.057)/h, T1/2 (3.1 +/- 1.1) h; High dose group: Ka (2.076 +/- 1.559)/h, tmax (1.7 +/- 0.3) h, Cmax (1336.5 +/- 366.0) microg/L, AUC0-14 (7481.5 +/- 2496.2) microg x h/L, Ke (0.266 +/- 0.051)/h, T1/2 (2.7 +/- 0.5) h. The pharmacokinetic parameters of erythromycin were as follows: Low dose group: Ka (1.410 +/- 0.626)/h, tmax (1.8 +/- 0.5) h, Cmax (197.5 +/- 227.6) microLg/L, AUC0-14 (766.4 +/- 981.0) microg x h/L, Ke (0.519 +/- 0.240)/ h, T1/2 (1.6 +/- 0.8) h. Middle dose group: Ka (1.900 +/- 1.049)/h, tmax (1.6 +/- 0.2) h,Cmax (488.3 +/- 216.7) microg/L, AUC0-14( 488.3 +/- 216.7) microg/L, Ke (0.329 +/- 0.057)/h, T1/2(2.2 +/- 0.4) h; High dose group: Ka (1.934 +/- 0.794)/h, tmax (1.7 +/- 0.3) h, Cmax (749.3 +/- 387.2) microg/L, AUC0-14(3820.1 +/- 1966.4) microg x h/L, Ke (0.373 +/- 0.174)/h, T1/2( 2.2 +/- 0.7) h. AUC of both erythromycin propionate and erythromycin base was linearly correlated to the doses; T1/2 was not correlated to the doses, so they followed the first order processes. The pharmacokinetic parameters of erythromycin The erythromycin stinoprate propionate and erythromycin base had no gender differences. Conclusion was absorbed as erythromycin propionate. Cmax reached at about 1.6 h. T1/2 of elimination was 2.4-3.1 h. The active component of erythromycin propionate was erythromycin. Cmax of erythromycin is 1.8, T1/2 is 2.4-3.1 h. In the range of oral dose of 250 to 750 mg, both erythromycin propionate and erythromycin base accorded the first order processes. The pharmacokinetic parameters were different with those reported in foreign documents while the gender difference did not exist in Chinese adults.

Delayed cardioprotection afforded by nitroglycerin is mediated by alpha-CGRP via activation of inducible nitric oxide synthase.

Previous investigations have demonstrated that delayed preconditioning induced by nitroglycerin is mediated by endogenous calcitonin gene-related peptide (CGRP). In the present study, we examined whether CGRP-mediated delayed preconditioning induced by nitroglycerin is involved in activation of inducible nitric oxide synthase (iNOS). Male Wistar rats were pretreated with nitroglycerin 24 h before the experiment, and then the left main coronary artery of rat heart was subjected to 60-min occlusion followed by 3 h reperfusion. Infarct size, the plasma level of cGMP and CGRP, and expression of CGRP isoforms (alpha-CGRP and beta-CGRP) mRNA in lumbar dorsal root ganglia were measured. Pretreatment with nitroglycerin (120 microg/kg, i.v.) markedly reduced infarct size. Nitroglycerin caused a significant increase in the expression of alpha-CGRP mRNA, but not beta-CGRP mRNA, concomitant with an increase in plasma concentrations of cGMP and CGRP. These effects of nitroglycerin were completely abolished by pretreatment with aminoguanidine (300 mg/kg, i.p.), a selective inhibitor of iNOS activity, or dexamethasone (5 mg/kg, i.p.), the iNOS expression inhibitor. The present results suggest that delayed cardioprotection afforded by nitroglycerin is mediated by the alpha-CGRP isoform via generation of NO derived from iNOS.

Demethylbellidifolin inhibits adhesion of monocytes to endothelial cells via reduction of tumor necrosis factor alpha and endogenous nitric oxide synthase inhibitor level.

The effect of demethylbellidifolin (DMB), a major compound of Swertia davidi Franch, on the adhesion of monocytes to endothelial cells induced by oxidized low-density lipoprotein (ox-LDL) was studied. Adhesion of monocytes to endothelial cells was induced by treatment with ox-LDL (100 microg/mL) for 48 h. Levels of tumor necrosis factor-alpha (TNF-alpha) and asymmetric dimethylarginine (ADMA, an endogenous inhibitor of NOS) in conditioned medium and the activity of dimethylarginine dimethylaminohydrolase (DDAH) in endothelial cells were measured. DMB (3 or 10 micromol/L) significantly inhibited the adhesion of monocytes to endothelial cells, attenuated an increase in levels of TNF-alpha and ADMA, and a decrease in the activity of DDAH by ox-LDL. The present results suggest that DMB inhibits the increased adhesion of monocytes to endothelial cells induced by ox-LDL, and that the effect of DMB is related to reduction of the ADMA concentration via reduction of TNF-alpha production in cultured endothelial cells treated with ox-LDL.