Gene/Protein Disease Symptom Drug Enzyme Compound
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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Felodipine is a potent arteriolar vasodilator. Its possible myocardial effects were studied by placing dogs anaesthetized with chloralose on cardiopulmonary bypass. A balloon was then inserted into the left ventricular cavity with a vent alongside it. Isovolumic contractions (developed pressure or maximal rate of rise of pressure) were studied as the intraventricular balloon was inflated to various levels. Total coronary venous return was collected to measure coronary blood flow and felodipine concentrations. In seven vagotomized and beta-blocked preparations, a small positive inotropic effect was found [32 +/- 11 (SEM)%, p less than 0.05]; the maximum effect was reached at arterial plasma felodipine concentrations of between 7 and 20 nM and was accompanied by appreciable coronary vasodilatation. In five dogs, infusion of the solvent vehicle (5% polyethylene glycol) alone had no effect. In three more dogs, an infusion of nitroprusside caused coronary vasodilatation, but no positive inotropic effect. The results show that at low concentrations, felodipine has a positive inotropic effect in vivo. These findings suggest that the properties of myocardial calcium agonist and vascular smooth muscle antagonist properties may coexist in the same dihydropyridine molecule. The favorable effects of this drug in the treatment of heart failure can be explained not only by reduction of peripheral resistance, but also by a moderate positive inotropic effect.
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PMID:The positive inotropic effect of felodipine in isovolumically beating dog heart. 244 2

In search for a new tocolytic agent we investigated felodipine, a calmodulin-antagonizing drug. Felodipine reduced the spontaneous activity of 22 uterine strips taken from the uterus in the course of a cesarean section to 52 +/- 12% (mean +/- SEM) after 10 min, to 20 +/- 7% after 20 min and to 12 +/- 4% after 60 min (P less than 0.001).
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PMID:Calcium and calmodulin antagonism for inhibition of uterine contractions. 273 73

Recently, calcium antagonists have been reported to have a clinically beneficial effect in patients with asthma. Felodipine is a new calcium antagonist of the dihydropyridine group with a high selectivity for arteriolar smooth muscle; it is under clinical investigation for the treatment of hypertension. In this double-blind, randomized crossover trial in 9 patients, the effect of 10 mg felodipine in oral solution on exercise-induced asthma was compared with a placebo on separate days. The FEV1 was at least 80% of the predicted normal value, with variation between study days of less than 10%. Heart rate, blood pressure, and FEV1 were measured before and at 15 and 30 min after each treatment. The exercise test consisted of steady state running at submaximal work loads for 6 to 8 min and started at 30 min after treatments. FEV1 was measured at 1, 2, 5, 10, 15, and 30 min after the end of exercise. The predrug baseline FEV1 values were comparable on the 2 days of the study, and felodipine had no effect on the resting lung function. The mean percentage fall in FEV1 (SEM) after exercise with placebo was 27.0 (4.5)%, and with felodipine it was 13.5 (3.7)%. The difference between felodipine and placebo was statistically significant. While receiving felodipine, the resting heart rate was increased by 15%, with a tendency to lower systolic and diastolic blood pressures. The heart rate after exercise was higher during felodipine treatment than during placebo treatment. One patient receiving placebo and 7 receiving felodipine noted a transient headache. Two patients receiving felodipine also noticed lightheadedness after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Felodipine, a new calcium antagonist, modifies exercise-induced asthma. 320

The natriuretic/diuretic effect of felodipine was investigated in 2 studies. The first was performed as an open study using intravenous and oral felodipine in healthy male subjects. The second was a double-blind study where a high and a low dose of oral felodipine were given to hypertensive patients on long term treatment with beta-blockers; the different doses of felodipine were chosen to decrease and to have no effect on the blood pressure, respectively. In both studies an oral placebo solution was used as a reference. Felodipine caused a significant increase in natriuresis. Compared with placebo and corrected for total 24-hour excretion, the sodium output during the first 4 hours after drug administration was increased by 219 +/- 53% (mean +/- SEM) after intravenous administration in healthy subjects (p less than 0.01) and by 80 +/- 43% in the first 3 hours after the high dose in hypertensive patients (p less than 0.05). For the same period, the urine excretion was increased by 114 +/- 38% (p less than 0.05) in the healthy subjects and by 36 +/- 22% in the hypertensive patients (not significant). However, the 24-hour excretion of urine, Na+ and K+ was not significantly changed from placebo. A significantly lower blood pressure was recorded after the higher dose (0.10 mg/kg) when given to hypertensive patients, but no such effect was seen after the lower dose (0.01 mg/kg) or in healthy subjects. The changes in diastolic blood pressure seem to be negatively correlated with the diuretic but not with the natriuretic effect.
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PMID:Acute diuretic/natriuretic properties of felodipine in man. 398 46

This study compared the efficacy and tolerability of monotherapy with felodipine and enalapril in patients with essential hypertension using a double-blind randomised crossover design. Thirty-five subjects (22 male, 13 female--ages: median 48 years, range 31-69 years) entered the randomised phases of the study and 32 subjects completed the study. Following a 4-week run-in placebo phase, the treatments were felodipine ("Plendil ER") 5-20 mg and enalapril 5-20 mg orally once daily for 8 weeks, each with matching placebos. Dose titration was at 2 and/or 4 weeks in each phase. Number of subjects with each different end-of-phase dose were for felodipine: 5 mg--8, 10 mg--11, 20 mg--13 and enalapril: 5 mg--6, 10 mg--9, 20 mg--17. Predose supine blood pressure (mean +/- SEM) was reduced in both active treatment phases compared with the run-in phase (159 + 2/101 +/- 1), but there was no significant difference in blood pressure between the active phases: felodipine 143 +/- 2/90 +/- 1 and enalapril 146 +/- 2/92 +/- 1. The most common adverse effects were for felodipine: headache, flushing, ankle swelling; and for enalapril: cough. Felodipine and enalapril as once daily monotherapy are thus of similar antihypertensive efficacy but with predictably different adverse effect profiles.
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PMID:Comparison of felodipine and enalapril monotherapy in essential hypertension. 819 32

The aim of the present study was to experimentally examine whether poorly water-soluble drugs dispersed in a polymeric matrix exist as amorphous nanodispersions or molecularly dispersed compounds. Felodipine (Felo) dispersed in PVP matrix (solid dispersion) was used as a model drug in this study. Drug/polymer ratios have an impact on the drug average particle size, morphology and dissolution profile while solid dispersions containing up to 50wt% Felo are completely amorphous. SEM, TEM micrographs, and micro-Raman mapping reveal that Felo is dispersed in the form of nanoparticles into the PVP matrix. Due to the high spatial resolution of TEM, it was established that these nanoparticles are not uniform particles, but rather agglomerates of individual particles with sizes smaller than 5-10nm. Moreover, micro-Raman mapping allowed us to observe the size and spatial distribution of domains where the drug existed as molecularly or nanodispersed. Experimental evidence presented in this work contradicts the common belief that amorphous poorly water-soluble drugs exist only in the state of molecular dispersion inside a polymer matrix by showing that both types of dispersions (molecular-level and nanodispersions) can coexist.
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PMID:Combining SEM, TEM, and micro-Raman techniques to differentiate between the amorphous molecular level dispersions and nanodispersions of a poorly water-soluble drug within a polymer matrix. 1747 64

In the present study, the efficiency of PVP/PEG200 mixtures as appropriate carries for the preparation of solid dispersions by melt mixing was evaluated. Felodipine (FELO) was used as a poorly water soluble model drug. The effect of several melt mixing parameters, (PVP/PEG ratio, time and temperature of melt mixing, and drug content), on the physical state of FELO and the dissolution characteristics of the dispersions were investigated. DSC, XRD, and SEM analysis revealed that in all cases, amorphous drug nanodispersions were prepared. This was attributed to the increased miscibility of the PVP-FELO system, induced by the presence of PEG200, which acted as plasticizer. FT-IR analysis showed hydrogen bonding between FELO (NH) and the PVP carrier (CO). The release rate of the drug depends mainly on the drug content and is higher in solid dispersions with low drug content and ratio of carrier to plasticizer (PVP/PEG200). The melt mixing variations (time and temperature of mixing) had lower impact on FELO release rate. Finally, artificial neural networks, used to correlate the examined formulation and process variables of hot melt mixing with dissolution parameters, showed good prediction ability.
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PMID:Optimizing the ability of PVP/PEG mixtures to be used as appropriate carriers for the preparation of drug solid dispersions by melt mixing technique using artificial neural networks: I. 2273 66

Among the many methods available for solubility enhancement, mesoporous carriers are generating significant industrial interest. Owing to the spatial confinement of drug molecules within the mesopore network, low solubility crystalline drugs can be converted into their amorphous counterparts, which exhibit higher solubility. This work aims to understand the impact of drug overloading, i.e., above theoretical monolayer surface coverage, within mesoporous silica on the release behaviour and the thermal properties of loaded drugs. The study also looks at the inclusion of hypromellose acetate succinate (HPMCAS) to improve amorphisation. Various techniques including DSC, TGA, SEM, assay and dissolution were employed to investigate critical formulation factors of drug-loaded mesoporous silica prepared at drug loads of 100-300% of monolayer surface coverage, i.e., monolayer, double layer and triple layer coverage. A significant improvement in the dissolution of both Felodipine and Furosemide was obtained (96.4% and 96.2%, respectively). However, incomplete drug release was also observed at low drug load in both drugs, possibly due to a reversible adsorption to mesoporous silica. The addition of a polymeric precipitation inhibitor HPMCAS to mesoporous silica did not promote amorphisation. In fact, a partial coating of HPMCAS was observed on the exterior surface of mesoporous silica particles, which resulted in slower release for both drugs.
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PMID:Delivery of Poorly Soluble Drugs via Mesoporous Silica: Impact of Drug Overloading on Release and Thermal Profiles. 3118 10