Sustained Release Nifedipine Formulations Springer.Link. Synopsis. Nifedipine antagonises influx of calcium through cell membrane slow channels, and sustained release formulations of the calcium channel blocker have been shown to be effective in the treatment of mild to moderate hypertension and both stable and variant angina pectoris.Preliminary findings also indicate that these formulations are effective in the treatment of Ray nauds phenomenon and hypertension in pregnancy, and that they reduce the frequency of ischaemic episodes in some patients with silent myocardial ischaemia.The exact mechanism of action of nifedipine in all of these disorders has not been defined.However, its potent peripheral and coronary arterial dilator properties, together with improvements in oxygen supplydemand, are of particular importance.A major goal of sustained release therapy is to permit reductions in the frequency of nifedipine administration, preferably to once daily, and thus improve patient compliance.QIsTar8qDEEANxJiP3w/320x470/1/crop/c0/6e/56c1b405e1cf6851038b8a02_56c1b405bef86.jpg' alt='Initial D Manga Volume 28 Ch 365 Microsoft' title='Initial D Manga Volume 28 Ch 365 Microsoft' />Two new once daily formulations the nifedipine gastrointestinal therapeutic system GITS and a fixed combination capsule comprising sustained release nifedipine 2.The GITS preparation has also been used effectively in the treatment of stable angina pectoris, and both formulations appear to be well tolerated.Family practices in later life, Pat Chambers, Graham Allan, Chris Phillipson.Studyguide Outlines Highlights.FOOD SCIENCE AND TECHNOLOGY.EDITORIAL BOARD. QUARTERLY PUBLICATION OF THE SBCTA VOLUME 351 2015.Suzana Caetano da Silva Lannes Universidade de So.Nifedipine antagonises influx of calcium through cell membrane slow channels, and sustained release formulations of the calcium channel blocker have been shown to be.Initial D Manga Volume 28 Ch 365 Microsoft WordSustained release nifedipine formulations are generally better tolerated than their conventionally formulated counterparts, particularly with regard to reflex tachycardia.Adverse effects seem to be dose related, are mainly associated with the drugs potent vasodilatory action, and include headache, flushing and dizziness.Generally, these effects are mild to moderate in severity and transient, usually diminishing with continued treatment.Thus, sustained release nifedipine formulations are useful and established cardiovascular therapeutic agents which have demonstrable efficacy in various forms of angina, mild to moderate hypertension and Raynauds phenomenon.Initial D Manga Volume 28 Ch 365 Microsoft EmailFurther, promising results shown by the nifedipine GITS formulation, with its advantage of once daily administration suggest that it is likely to become one of the preferred nifedipine formulations for the treatment of hypertension and the various forms of angina.Pharmacodynamic Properties.Nifedipine inhibits influx of calcium through cardiac muscle and vascular smooth muscle cell membranes.It differs from diltiazem and verapamil, particularly with regard to sinoatrial and atrioventricular node function, where it may enhance conduction.Repeated administration of sustained release nifedipine reduces systolic and diastolic blood pressure by about 1.GITS reduce blood pressure by approximately 2.Administered once daily, the latter formulation effectively controls blood pressure in a dose dependent manner throughout a 2.Single doses of conventional nifedipine formulations increase heart rate by 1.In contrast to conventional nifedipine formulations, sustained release preparations are generally not associated with postdose tachycardia.The main haemodynamic actions of nifedipine are peripheral arterial vasodilation with subsequent reductions in systemic vascular resistance and afterload, and an increase in cardiac index.Nifedipine has a small, direct negative inotropic effect in vitro and after intracoronary administration to humans.This is usually not observed after oral administration.Sustained release nifedipine may increase cardiac output, and it increased cardiac efficiency and reduced cardiac power in patients with hypertension. 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Further, the fixed combination sustained release nifedipine atenolol formulation caused a marked regression of left ventricular hypertrophy after 1 years treatment.Nifedipine has antianginal effects which parallel those of diltiazem, verapamil, blockers and nitrates.It improves clinical status and reduces ECG signs of myocardial ischaemia on exercise or atrial pacing.In addition, it increases coronary blood flow, particularly to myocardial areas supplied by stenotic arteries, without significantly altering myocardial oxygen consumption.Nifedipine also relieves coronary vasospasm in variant Prinzmetal angina, and improves exercise performance by reducing myocardial oxygen demand in patients with effort angina.Generally, the vasocdlating action of nifedipine is greater in hypertensive patients than in normotensive volunteers.Nifedipine significantly increases forearm blood flow and brachial artery compliance, while significantly reducing forearm vascular resistance and characteristic impedance.Nifedipine reduces plasma levels of thromboglobulin, a protein released during platelet activation, in patients with Raynauds phenomenon, and reverses thrombocytopenia in women with pre eclampsia.Data regarding the effect of nifedipine on serum lipids are conflicting with reports of no significant effects, increases in high density lipoprotein HDL, HDL2 and apolipoprotein A I and A II, and significant decreases in apolipoprotein E, and low density lipoprotein LDL HDL and apolipoprotein B A I ratios.However, animal experiments have indicated that nifedipine may slow the progression of new atherosclerotic lesions.This was confirmed in the International Nifedipine Trial on Antiatherosclerotic Therapy INTACT in which nifedipine formulation not stated significantly reduced the progression of new atherosclerotic lesions in patients with mild to moderate coronary artery disease.Administration of sustained release nifedipine for 6 to 5.In a large number of single dose studies involving healthy volunteers and subjects with impaired glucose tolerance or diabetes, nifedipine also had no significant effect on glucose tolerance.Thus, the weight of evidence indicates that nifedipine has no real diabetogenic potential.Nifedipine rarely has marked renal effects.However, renal blood flow increases significantly and renovascular resistance decreases significantly after 4 weeks nifedipine administration to patients with essential hypertension.Nifedipine increases glomerular filtration rate 1.Increases in plasma renin activity are noted after the acute administration of nifedipine, whereas during longer term administration both increases and decreases in plasma renin activity have been recorded.Plasma aldosterone levels do not change in parallel with alterations in plasma renin activity.However, angiotensin II levels increase, particularly in younger normotensive and hypertensive subjects.Nifedipine has significant diuretic and natriuretic actions, may also significantly increase urinary potassium excretion, and has a significant uricosuric action.Pharmacokinetic Properties.Nifedipine is almost completely absorbed from the jejunum after the administration of an oral dose.However, as a result of extensive and variable first pass hepatic extraction, it has a relatively low bioavailability ranging from 4.Absorption of nifedipine from sustained release oral tablets is prolonged tmax1.Food increases the bioavailability of a sustained release nifedipine tablet and may also delay gastric emptying, thereby increasing the dissolution of a biphasic nifedipine formulation in the stomach.Nifedipines absorption from the gastrointestinal therapeutic system GITS is unaffected by gastrointestinal p.H or motility. This formulation has an oral bioavailability of 5.As with other nifedipine formulations, the GITS tablet exhibits a linear pharmacokinetic profile and plasma nifedipine concentrations begin to rise 2 hours after, and plateau approximately 6 hours after, GITS administration.Dose dumping does not occur with this sustained release formulation, and although food increases the rate of absorption of nifedipine from the GITS this is not associated with alterations in bioavailability.The mean steady state apparent volume of distribution of nifedipine is 1.Lkg after oral administration.Nifedipine is highly bound to plasma proteins 9.Assuming complete absorption of an orally administered nifedipine dose, about 3.Nifedipine undergoes oxidation to 3 pharmacologically inactive metabolites which are subsequently excreted in the urine together with traces of unchanged nifedipine.Two types of nifedipine metaboliser fast and slow have been postulated.These may arise because of oxidation polymorphism with a genetic basis.Mexican populations may have a prevalence of slow metabolisers, whereas fast metabolisers may be found more frequently in European populations.Food Science and Tecnology, volume 3.Editora Cubo. Food Science and Tecnology, volume 3.Published on Mar 2.Food Science and Tecnology, volume 3.Food Science and Technology is published four times a year by the Sociedade Brasileir.
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