Quantitative determination of indapamide in pharmaceuticals and urine by high-performance liquid chromatography with amperometric detection.
A high-performance liquid chromatographic method with amperometric detection for the determination of the diuretic indapamide using a muBondapak C18 column is developed. The mobile phase consists of an acetonitrile-water mixture (45:55, 5 mM) in KH2PO4-K2HPO4 (pH 4.0). The compound is monitored at +1200 mV with an amperometric detector equipped with a glassy carbon working electrode. A liquid-liquid or solid-liquid extraction is performed prior to chromatographic analysis to avoid the interferences found in urine matrix. Percentages of recovery are 88.3 +/- 5.6 and 82.9 +/- 7.8 for liquid-liquid and solid-liquid extraction, respectively. The developed method has a linear concentration range from 25 to 315 ng/mL with a reproducibility in terms of relative standard deviation of 4% for a concentration level of 0.5 microgram/mL and a quantitation limit of 1 ng/mL. The method is applied to the determination of indapamide in tablets and urine obtained from hypertensive patients after the ingestion of Tertensif (indapamide 2.5 mg). (+info)
Functional consequences of the arrhythmogenic G306R KvLQT1 K+ channel mutant probed by viral gene transfer in cardiomyocytes.
IKs, the slow component of the delayed rectifier potassium current, figures prominently in the repolarization of heart cells. The K+ channel gene KvLQT1 is mutated in the heritable long QT (LQT) syndrome. Heterologous coexpression of KvLQT1 and the accessory protein minK yields an IKs-like current. Nevertheless, the links between KvLQT1 and cardiac IKs are largely inferential. Since the LQT syndrome mutant KvLQT1-G306R suppresses channel activity when coexpressed with wild-type KvLQT1 in a heterologous system, overexpression of this mutant in cardiomyocytes should reduce or eliminate native IKs if KvLQT1 is indeed the major molecular component of this current. To test this idea, we created the adenovirus AdRMGI-KvLQT1-G306R, which overexpresses KvLQT1-G306R channels. In > 60 % of neonatal mouse myocytes, a sizable IKs could be measured using perforated-patch recordings (8.0 +/- 1.6 pA pF-1, n = 13). IKs was increased by forskolin and blocked by clofilium or indapamide but not by E-4031. While cells infected with a reporter virus expressing only green fluorescent protein (GFP) displayed IKs similar to that in uninfected cells, AdRMGI-KvLQT1-G306R-infected cells showed a significantly reduced IKs (2.4 +/- 1.1 pA pF-1, n = 10, P < 0.01) when measured 60-72 h after infection. Similar results were observed in adult guinea-pig myocytes (5.9 +/- 1.2 pA pF-1, n = 9, for control vs. 0.1 +/- 0.1 pA pF-1, n = 5, for AdRMGI-KvLQT1-G306R-infected cells). We conclude that KvLQT1 is the major molecular component of IKs. Our results further establish a dominant-negative mechanism for the G306R LQT syndrome mutation. (+info)
Improvement in blood pressure, arterial stiffness and wave reflections with a very-low-dose perindopril/indapamide combination in hypertensive patient: a comparison with atenolol.
International guidelines recommend that antihypertensive drug therapy should normalize not only diastolic (DBP) but also systolic blood pressure (SBP). Therapeutic trials based on cardiovascular mortality have recently shown that SBP reduction requires normalization of both large artery stiffness and wave reflections. The aim of the present study was to compare the antihypertensive effects of the very-low-dose combination indapamide (0.625 mg) and perindopril (2 mg) (Per/Ind) with the beta-blocking agent atenolol (50 mg) to determine whether Per/Ind decreases SBP and pulse pressure (PP) more than does atenolol and, if so, whether this decrease is predominantly due to reduction of aortic pulse wave velocity (PWV) (automatic measurements) and reduction of wave reflections (pulse wave analysis, applanation tonometry). In a double-blind randomized study, 471 patients with essential hypertension were followed for 12 months. For the same DBP reduction, Per/Ind decreased brachial SBP (-6.02 mm Hg; 95% confidence interval, -8.90 to -3.14) and PP (-5.57; 95% confidence interval, -7.70 to -3.44) significantly more than did atenolol. This difference was significantly more pronounced for the carotid artery than for the brachial artery. Whereas the 2 antihypertensive agents decreased PWV to a similar degree, only Per/Ind significantly attenuated carotid wave reflections, resulting in a selective decrease in SBP and PP. The very-low-dose combination Per/Ind normalizes SBP, PP, and arterial function to a significantly larger extent than does atenolol, a hemodynamic profile that is known to improve survival in hypertensive populations with high cardiovascular risk. (+info)
Sodium intake, large artery stiffness, and proteoglycans in the spontaneously hypertensive rat.
Although the role of sodium in hypertension has been documented extensively, its effect on large arteries has not been well documented. We examined the effect of high-sodium (8%) diet and the diuretic indapamide (IND) on systemic hemodynamics and aortic wall structure and composition in collagen, elastin, and hyaluronan. Four groups of spontaneously hypertensive rats (SHR) were studied after 8 weeks: those on a normal diet (SHR), a high-sodium diet (SHR+NaCl), a normal diet with IND (SHR+IND), and a high-sodium diet with IND (SHR+NaCl+IND). Mean BP, which was not normalized with IND, was comparable for all groups. Systemic arterial compliance averaged 3.8, 2.5, 4.9, and 3.3 mL/mm Hg. 10(-3), respectively, for the SHR, SHR+NaCl, SHR+IND, and SHR+NaCl+IND groups (P<0.003 and <0.05 for NaCl and IND effects). Wall thickness increased only in the SHR+NaCl group (P<0.01). Aortic wall COL decreased from 16 116 in the SHR to 12 382 micrometer(2)/mm in the SHR+NaCl+IND (P<0.005) group. IND alone had no effect on elastin, but the elastin/collagen ratio was increased significantly. Aortic hyaluronan averaged 2343, 266, 3243, and 1052 micrometer(2)/mm, respectively, for the SHR, SHR+NaCl, SHR+IND, and SHR+NaCl+IND groups (P<0.0001 for NaCl and IND effects). Changes in systemic arterial compliance were significantly and positively correlated with aortic hyaluronan contents. Thus, high-sodium diet affects the structural and functional characteristics of large arteries independently of BP. A high-sodium diet, in addition to a diuretic regimen with IND, affects simultaneously aortic hyaluronan contents and large artery mechanical properties through pressure-independent mechanisms that remain to be defined. (+info)
Molecular and functional characterization of ERG, KCNQ, and KCNE subtypes in rat stomach smooth muscle.
Contribution of K(+) channels derived from the expression of ERG, KCNQ, and KCNE subtypes, which are responsible for rapidly and slowly activating delayed rectifier K(+) currents (I(Kr) and I(Ks), respectively) in cardiac myocytes, to membrane currents was examined in stomach circular smooth muscle cells (SMCs). The region-qualified multicell RT-PCR showed that ERG1/KCNE2 transcripts were expressed in rat stomach fundus and antrum SMCs and that KCNQ1/KCNE1 transcripts were expressed in antrum but not fundus. Western blotting and immunocytochemical analyses indicate that ERG1 proteins were substantially expressed in both regions, whereas KCNE1 proteins were faintly expressed in antrum and not in fundus. Both I(Kr)- and I(Ks)-like currents susceptible to E-4031 and indapamide, respectively, were identified in circular SMCs of antrum but only I(Kr)-like current was identified in fundus. It is strongly suggested that I(Kr)- and I(Ks)-like currents functionally identified in rat stomach SMCs are attributable to the expression of ERG1/KCNE2 and KCNQ1/KCNE1, respectively. The membrane depolarization by 1 microM E-4031 indicates the contribution of K(+) channels encoded by ERG1/KCNE2 to the resting membrane potential in stomach SMCs. (+info)
Efficacy of very low dose perindopril 2 mg/indapamide 0.625 mg combination on left ventricular hypertrophy in hypertensive patients: the P.I.C.X.E.L. study rationale and design.
The PICXEL study is designed to evaluate the effects of long-term administration of very low-dose combination perindopril 2 mg/indapamide 0.625 mg (Per/Ind) vs enalapril in reducing left ventricular hypertrophy (LVH) in hypertensive patients. This multicentre, controlled, randomised, double-blind, parallel group study is carried-out to assess the variation of left ventricular mass index (LVMI) after treatment, using a centralised control of M-mode echocardiography determinations, and a dedicated software for semi-automatic measurement. Following a 4-week placebo run-in period, hypertensive outpatients aged >/=18 years, with LVH (LVMI >120 and 100 g/m(2) for men and women, respectively), are randomised to receive once daily, over 52 weeks, either Per/Ind or enalapril. According to blood pressure levels, the dose may be adjusted. In addition to clinical examinations, ECG, blood pressure, heart rate and laboratory assessments echocardiographic determinations are performed for selection, at baseline, after 24 weeks and at the end of the study. The main outcome criteria is the change from baseline in LVMI which is considered the primary efficacy criterion; changes in blood pressure and echo-Doppler parameters constitute secondary criteria. Two-sided Student's t-test for independent samples will be used to differentiate the effects of the treatment between groups with alpha = 5%, and the inter-group difference of LVMI variation will be analysed with a power of 90%. A sample size of 500 patients is required making it necessary to randomise at least 550 patients, based on a 10% proportion of potentially non-assessable patients. The results of this study, obtained after applying strict methodological procedures and requirements, are expected to provide valuable and reliable information on the effects of long-term administration of Per/Ind on LVH, and on its potential superiority over enalapril. (+info)
Very-low-dose combination of the angiotensin-converting enzyme inhibitor perindopril and the diuretic indapamide induces an early and sustained increase in neovascularization in rat ischemic legs.
After acute ischemia of tissues, neovascularization must be sufficient and fast enough to preserve tissue integrity and organ function, and may thus be considered as a therapeutic strategy. This study examined the possible role of the very-low-dose combination of perindopril (angiotensin-converting enzyme inhibitor) and indapamide (diuretic), used first-line in the treatment of essential hypertension, on ischemia-induced angiogenesis. Ischemia was produced by artery femoral occlusion in rats treated or not with the very-low-dose combination (perindopril 0.76 mg/kg/day + indapamide 0.24 mg/kg/day) or each component given alone at the same dosage for 3 and 28 days. At day 3, angiographic vessel density and laser Doppler perfusion data showed significant improvement in ischemic/nonischemic leg ratio by, respectively, 1.9-fold and 1.5-fold in rats treated with the very-low-dose combination when compared with controls (p < 0.05). This was associated with an increase in vascular endothelial growth factor (VEGF; 2.2-fold) and endothelial nitric-oxide synthase (1.6-fold) protein content in the ischemic hindlimb, assessed by Western blot. At day 28, the very-low-dose combination (3- and 1.6-fold) and perindopril alone (1.8- and 1.4-fold) and indapamide alone (2.0- and 1.4-fold) increased the angiograhic score and blood flow perfusion, respectively, in reference to controls (p < 0.05). Furthermore, addition of VEGF-neutralizing antibody (2.5 microg/kg twice a week) or NOS inhibitor (N(G)-nitro-L-arginine methyl ester, 10 mg/kg/day) prevented the pro-angiogenic effect induced by the perindopril/indapamide combination. The very-low-dose combination of perindopril and indapamide induces an early and sustained effect on the revascularization process observed in ischemic tissue and may provide a favorable therapeutic neovascularization after ischemia. (+info)
Effects of four antihypertensive monotherapies on cardiac mass and function in hypertensive patients with left ventricular hypertrophy: randomized prospective study.
AIM: To compare the effects of four antihypertensive drugs, which have reportedly different effectiveness in reducing myocardial mass. METHODS: A randomized, double-blind, prospective study included 80 hypertensive patients with left ventricular (LV) hypertrophy confirmed both electrocardiographically and echocardiographically. We investigated the effects of indapamide, nicardipine, propranolol, and chlorthalidone on arterial blood pressure and LV mass and function. RESULTS: Sixty-four patients (34 men and 30 women) completed the 6-month study. No significant differences in antihypertensive effects of the four medications were found. The average decrease in systolic and diastolic blood pressure was 12.8% and 10.4%, respectively. All four antihypertensive medications caused pronounced reduction in LV mass, between 7.9% in the propranolol group and 10.1% in the nicardipine group, with no significant difference between the groups. In patients receiving diuretics, predominant decrease was observed in LV mass and LV mass index. In patients treated with propranolol, the thickness of both the LV wall and interventricular septum was reduced, whereas the reduction in LV mass, LV wall and interventricular septum thickness was found in patients treated with nicardipine. There was no significant correlation between the changes in LV mass and other variables (blood pressure, and systolic and diastolic function). Systolic function did not improve with the reversion of LV hypertrophy in any group of patients, but improvement was observed in some indices of diastolic function. The early and late LV filling velocity and their ratio did not improve significantly, either. Clinically relevant side effects were not observed. CONCLUSION: All four antihypertensive monotherapies achieved a comparable control of hypertension and reduction in LV hypertrophy. (+info)