scholarly journals In Vitro Model of Brain Trauma: in Isolated Basilar Artery Hemolysed Blood‐induced Constriction is Inhibited by Calcium Channel Blocker and Increased CO 2

2015 ◽  
Vol 29 (S1) ◽  
Author(s):  
Akos Koller ◽  
Orsolya Torok ◽  
Zoltan Vamos ◽  
Peter Cseplo
Author(s):  
Surya Teja S P ◽  
Manisha Khandelwal ◽  
Chitra V ◽  
Damodharan N

  Objective: Felodipine, a BCS class II calcium channel blocker, is used in the management of hypertension and angina pectoris. Due to the poor solubility and low bioavailability of the drug, there is a necessity to design an alternative route to achieve a constant plasma concentration of felodipine for its maximum therapeutic utility and can be achieved by transdermal route.Methods: In this study, matrix type transdermal patches were prepared using different combinations of hydrophilic polymer, namely, polyvinylpyrrolidone (PVP) and hydrophobic polymer, namely, ethyl cellulose (EC) by solvent evaporation technique and were subjected for characterization.Results: The Fourier transform infrared studies confirmed the compatibility between drug and polymers. Hydrophilic nature of the polymers greatly influenced physical characteristics and dissolution rate. Equal percentage of PVP and EC yielded patches with good folding endurance. The concentration of plasticizer present in the patches gave them desired folding endurance, and it increased with the presence of hydrophilic polymer. The formulation with highest PVP concentration, F3, exhibited a maximum drug release of 96.23% for 24 hrs. While the formulation with highest EC concentration, F5, exhibited only 74.45% drug release for 24 hrs.Conclusion: From the data, formulation F2 (PVP/EC, 2:1) can be concluded as best formulation due to its desired physical characteristics, good initial drug release, sustained release behavior, and good in vitro permeation. This formulation can be further studied in a clinical scenario.


2011 ◽  
Vol 128 (2) ◽  
pp. 111-115 ◽  
Author(s):  
Juliana Q. Reimão ◽  
Fábio A. Colombo ◽  
Vera L. Pereira-Chioccola ◽  
André G. Tempone

1996 ◽  
Vol 30 (7-8) ◽  
pp. 802-810 ◽  
Author(s):  
Joseph J Saseen ◽  
Barry L Carter

OBJECTIVE: To review the in vitro receptor binding data of calcium-channel blockers (CCBs) and in vivo studies in humans regarding the use of dual calcium-channel blocker therapy, with a focus on the use of this therapy for hypertens DATA SOURCE: A MEDLINE search was conducted to identify literature pertaining to CCBs. STUDY SELECTION: In vitro studies and investigations that evaluated CCB receptor binding and the interactions between subclasses of CCBs were chosen. All studies in humans and clinical trials that evaluated the use of dual CCB therapy in the treatment of cardiovascular diseases were selected for review. Also, case reports describing the use of dual CCB therapy were included in this article. DATA EXTRACTION: The methodology, results, and conclusions of the selected data were evaluated. Data regarding the in vitro receptor binding kinetics of CCBs, as well as interactions, were reported. Because there is limited information on dual CCB therapy for hypertension, clinical studies using this treatment for ischemic heart disease were also reviewed. They were summarized and compared on the basis of the degree of disease control (e.g., blood pressure, exercise tolerance), adverse effects, and other clinical endpoints of pharmacologic therapy. DATA SYNTHESIS: In vitro studies have identified binding sites for the dihydropyridine (nifedipine), diphenylalkylamine (verapamil), and benzothiazepine (diltiazem) subclasses of CCBs, and indicate that they are allosterically related to each other within the voltage-sensitive calcium-channel receptor. Dihydropyridine binding affinity is decreased with concomitant verapamil binding, but is enhanced by concomitant diltiazem binding. Dual CCB therapy has been shown to be efficacious in patients with ischemic heart disease. Although this therapy is limited by dose-related adverse effects, it appears to have an important role in patients with ischemia that is refractory to conventional therapy, or for those whose therapeutic options are limited by contraindications. Theoretically, many patients with hypertension may benefit similarly from dual CCB therapy. Because data evaluating this treatment option are sparse, recommendations regarding safety, efficacy, and the role of dual CCB therapy for hypertension would be premature. CONCLUSIONS: Controlled data evaluating dual CCB therapy for the treatment of hypertension are lacking. This treatment modality may be beneficial in the future, but requires further investigation to determine safety and efficacy.


1984 ◽  
Vol 62 (6) ◽  
pp. 640-644 ◽  
Author(s):  
A. Chaudhry ◽  
M. M. Vohra

The actions of the calcium-channel blocker D-600 on cardiac noradrenaline stores were investigated by giving rats the drug systemically and then using a high-performance liquid chromatograph equipped with an electrochemical detector to determine the noradrenaline content of their hearts. A single 5-mg/kg dose of D-600 caused a significant depletion of noradrenaline content of the ventricles (approximately 31%) but not of the auricles. However, when multiple doses of D-600 were given at 12-h intervals, the depletion of cardiac noradrenaline content was more marked and both the auricular and ventricular contents were significantly decreased. Depletion of noradrenaline content was maximal 4 h after administration of D-600. A partial recovery of noradrenaline content occurred 16 h after administration of D-600, indicating that this effect of D-600 is reversible. In in vitro studies, D-600 (10−7 to 10−3 M) evoked a dose-related increase in the basal outflow of tritium from the rat isolated atria preloaded with [3H]noradrenaline ([3H]NA), indicating that depletion of cardiac noradrenaline stores by D-600 may be due to a direct action on sympathetic nerves rather than to increased reflex sympathetic activity secondary to profound vasodilation caused by the drug. The metabolic profile of tissue 3H content and of D-600-evoked 3H overflow was also examined. Whereas >90% of tissue 3H content consisted of unchanged [3H]NA, 60–70% of the D-600-evoked overflow consisted of [3,4-3H]dihydroxyphenylglycol, and approximately 5% was unchanged NA, thus indicating that D-600 causes release of [3H]NA intraneuronally. It is concluded that this property of D-600 might be responsible for the depletion of endogenous cardiac noradrenaline stores after systemic administration of the drug to rats.


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