Azelnidipine

Description

Azelnidipine, a member of the 1,4-dihydropyridine class of L-type calcium channel blockers with a slow onset profile, was marketed in Japan for the treatment of hypertension. Azelnidipine is synthesized via the condensation of iso-propyl 2-(3- nitrobenzylidene)acetoacetate with (1-diphenylmethylazetidin-3-yl)-3,3-diamino acrylate. The diamino acrylate intermediate is prepared from the cyanoacetic ester by sequential treatment with HCl and ammonia. In receptor binding studies using porcine heart membrane fractions, azelnidipine exhibits an IC₅₀ of 3.1 nM and an apparent K_i of 2.1 nM. Its tight binding and slow onset are correlated with its high lipophilicity. A slow onset is also noted in vitro in a rat aortic strip contraction assay, and this effect continues after removal of the drug from the bath solution. In the conscious spontaneously hypertensive rat (SHR) model of hypertension, it was more potent that nicardipine and also had a more gradual onset and long-lasting effect. This effect was noted both when dosed orally or intravenously. When SHR dosed at 1 or 3 mpk/day for 15 weeks, a sustained reduction in systolic blood pressure was noted (19 and 43 mmHg reduction, respectively). Cardiac output was increased and total peripheral resistance was decreased in each group. Clinical studies of patients with mild-to-moderate hypertension have shown that long-term treatment with azelnidipine provided a sustained decrease in blood pressure (mean reduction systolic /diastolic: 27.8/16.6 mmHg). It similarly controlled blood pressure, as did amlodipine at 24 h. It possesses a gradual onset of activity with plasma levels increasing before the antihypotensive effect is attained. After plasma levels drop, the pharmacodynamic effect is sustained. In clinical studies, azelnidipine did not show reflex tachycardia, a common side effect of this class. Most common side effects were facial flushing and headache, similar to other dihydropyridines. Azelnidipine is dosed orally once daily (8–16 mg), is rapidly absorbed in a dose-dependent fashion, and has a mean terminal half-life of 19.2 h (8 mg dosage p.o. for seven days). Uniquely, it possesses a 2-amino function associated with a longer half-life than related agents wherein this moiety is a methyl. The very highly lipophilic 3-carboxylic ester side-chain is purported to contribute to the gradual onset of activity and prolonged pharmacodynamic effect, unlike other drugs in this class. This compound exhibits a much less pronounced first-pass metabolic effect than nicardipine.

Chemical Properties

Yellow Solid

Originator

Sankyo (Japan)

Uses

Azelnidipine is a dihydropyridine calcium channel blocker with antihypertensice activity. Azelnidipine is used for treating ischemic heart disease and cardiac remodeling after myocardial infarction. S tudies show that Azelnidipine ttreatment can reduce the risk of hyperglycemia induced metabolic disorders

Definition

ChEBI: Azelnidipine is an isopropyl ester.

Application

Azelnidipine is a novel dihydropyridine derivative, a L-type calcium channel blocker, and an antihypertensive. Acute administration of azelnidipine prevents a sudden drop of cardiac function after acute stress. Azelnidipine may have a protective role in inflammation associated with atherosclerosis.

brand name

Calblock

Biological Activity

Azelnidipine, a novel dihydropyridine derivative, is a L-type calcium channel blocker and antihypertensive. Unlike other L-type calcium channel blockers, azelnidipine causes minimal stimulation of the sympathetic nervous system despite its significant depressor effect. Azelnidipine may have a protective role in inflammation in atherosclerosis.

Synthesis

A solution of benzhydrylamine (46) and epichlorohydrin (47) was mixed without adding solvent to give azetidinol 48 in 57% yield. DCC coupling between cyanoacetic acid (49) and azetidinol 48 in hot THF gave ester 50 in 93% yield. Cyanoester 50 was treated with ethanol and HCl gas in chloroform to give imidate HCl salt 51, which was treated with ammonia gas in chloroform and ammonium acetate in acetonitrile to give the corresponding amidinoacetate 52. A modified Hantzsch reaction was employed to construct the 2-amino-1,4- dihydropyridine core structure. Compound 52 was condensed with 2-(3-nitrobenzylidene)acetic acid isopropyl ester (55) in the presence of NaOMe in refluxing isopropanol to give the cyclized product, azelnidipine (V) in 74% yield. Benzylideneacetoacetate 55 was obtained through the Knoevenagel reaction employing 3-nitrobenzaldehyde (53) and isopropyl acetoacetate (54) in isopropanol containing a catalytic amount of piperidinium acetate at 45-55oC in 65% yield.