Prognostic Value of Myocardial Perfusion SPECT After Intravenous Bolus Administration of Nicorandil in Patients with Acute Ischemic Heart Failure.

UNLABELLED: Nicorandil, a hybrid adenosine triphosphate (ATP)-sensitive potassium channel opener and nitrate, is commonly used for the management of acute ischemic heart failure (AIHF). The aims of this study were to predict the effect of nicorandil by calculating myocardium-to-background ratio increasing rate (MBR-IR) using nicorandil stress myocardial perfusion SPECT and to evaluate the prognostic value of MBR-IR in patients with AIHF. METHODS: Twenty-two patients (age, 70 ± 12 y) admitted to the coronary care unit with AIHF underwent nicorandil-stress and rest myocardial perfusion SPECT. Using these images, MBR-IR was calculated by dividing stress MBR by rest MBR (MBR = peak value of left ventricular myocardial segments/mean value of upper mediastinum). In order to evaluate the clinical importance of MBR-IR derived from the nicorandil-stress test, all patients were divided into 2 groups, based on the value of MBR-IR. All patients were observed over 5 y from the onset of AIHF for the occurrence of major adverse cardiac events (MACE). RESULTS: Both high- and low-MBR-IR groups contained 11 participants. Median MBR-IR was 1.55 (1.34-1.61) in the high-MBR-IR group and 1.08 (1.02-1.10) in the low-MBR-IR group. The proportion of patients who experienced MACE was significantly higher in the low-MBR-IR group than in the high-MBR-IR group (91% vs. 18%, P < 0.001). CONCLUSION: This study demonstrated that the MBR-IR calculated using nicorandil-stress myocardial perfusion SPECT may have a high prognostic value for MACE in patients with AIHF.

Development, optimization, and characterization of polymeric electrospun nanofiber: a new attempt in sublingual delivery of nicorandil for the management of angina pectoris.

The objective of the current investigation was to develop a novel biocomposite polymeric nanofiber for sublingual delivery of nicorandil in an attempt to reduce mucosal ulceration and to improve drug bioavailability. Polymeric nanofibers were achieved using vitamin B12 and a blend of hyaluronic acid and polyvinyl alcohol as polymeric constituents. The electrospinning method was used to prepare drug (nicorandil)-loaded nanofibers. The resulting nanofibers were characterized for morphology, drug loading, XRD, DSC, in vitro drug release, degree of swelling, and pharmacokinetic behavior. The prepared nanofibers were found to be uniform, non-beaded, and non-woven, with fiber diameter ranging from 200-450 nm. In vitro drug release substantiated the controlled release behavior of the developed formulation. Histopathology studies demonstrated no evidence of mucosal ulceration at the site of application. Pharmacokinetic studies established the preclinical safety and showed the maintenance of an effective therapeutic level for a prolonged period. The present investigation gives inputs showing that the biocomposite nanofiber assists as a perfect carrier system for sublingual delivery of anti-anginal drugs.

Synthesis, antinociceptive activity and pharmacokinetic profiles of nicorandil and its isomers.

Nicorandil (N-(2-hydroxyethyl)nicotinamide nitrate) is an antianginal drug, which activates guanylyl cyclase and opens the ATP-dependent K(+) channels, actions that have been suggested to mediate its vasodilator activity. We synthesized nicorandil and its two isomers, which vary in the positions of the side chain containing the nitric oxide (NO) donor, and also their corresponding denitrated metabolites. The activities of these compounds were evaluated in an experimental model of pain in mice. Pharmacokinetic parameters of nicorandil and its isomers, as well as the plasma concentrations of the corresponding denitrated metabolites and also nicotinamide and nitrite were determined. Nicorandil exhibited the highest antinociceptive activity, while the ortho-isomer was the least active. Nicorandil and para-nicorandil, which induced higher plasma concentrations of nitrite, exhibited higher antinociceptive activity, which suggests that the release of NO may mediate this activity.

Nicorandil: from ulcer to fistula into adjacent organs.

Nicorandil is an original vasodilatator used to control angina by decreasing cardiac preload and afterload. Since 1997, many reports of single or multiple nicorandil-induced ulcerations have been published. To date, eight cases of nicorandil-induced fistula into adjacent organs have been described. The pathogeneses of nicorandil-induced ulceration and fistula into adjacent organs are not yet elucidated. The two main hepatic biotransformation pathways of nicorandil are denitration and reduction of the alkyl chain leading to nicotinamide and niconitic acid which merge into the endogenous pool of nicotinamide adenine dinucleotide/phosphate. This merging which is known as saturable, may contribute to a slow and abnormal distribution of nicotinamide and nicotinic acid out of the endogenous pool. Under these special conditions, providing these two molecules in situ, nicotinic acid associated with nicotinamide may ulcerate rather recent or maintained trauma. Ulcers and fistulae induced by nicorandil heal after withdrawal. Surgical intervention is unnecessary and inappropriate as it is ineffective and exacerbates morbidity. All practitioners should be correctly informed about these serious but preventable nicorandil side effects, which mostly occur in the elderly and fragile population. In the absence of corrective measures, withdrawal of this original and active drug should be considered.

Enantioselective penetration enhancing effect of carvone on the in vitro transdermal permeation of nicorandil.

The objective was to investigate the difference in penetration enhancing effect of R-carvone, S-carvone and RS-carvone on the in vitro transdermal drug permeation. In vitro permeation studies were carried out across neonatal rat epidermis from 2%w/v HPMC (hydroxypropyl methylcellulose) gel containing 4%w/v of nicorandil (a model drug) and a selected concentration (12%w/v) of either R-carvone, S-carvone or RS-carvone against a control. The stratum corneum (SC) of rats was treated with vehicle (70%v/v ethanol-water) or ethanolic solutions of 12%w/v R-carvone, S-carvone or RS-carvone. The enhancement ratio (ER) of R-carvone, S-carvone and RS-carvone when compared to control was about 37.1, 31.2 and 29.9, respectively indicating enantioselective penetration enhancing effect of carvone enantiomers. Furthermore, there was a significant decrease in the lag time required to produce a steady-state flux of nicorandil with S-carvone when compared to R-carvone and RS-carvone. DSC and FT-IR studies indicate that the investigated enantiomers of carvone exhibit a difference in their ability to affect the cellular organization of SC lipids and proteins thereby showing enantioselective transdermal drug permeation. It was concluded that R-carvone exhibited a higher penetration enhancing activity on transdermal permeation of nicorandil when compared to its S-isomer or racemic mixture.

[Cardioprotective characteristics of the drug nicorandil in patients with coronary heart disease].

Nicorandil, opener of potassium channels, was studied in Russia and abroad. Its cardioprotective, anti-ischemic, pharmacokinetic and pharmacodynamic properties are reviewed as well as side effects and area of application in patients with stable coronary heart disease (CHD). The trial have found efficacy of nicorandil in prevention of anginal attacks. Also, the drug increases exercise tolerance. Administration of nicorandil is indicated before intervention on coronary arteries for reproduction of the effect of myocardial preconditioning. Nicorandil is recommended for treatment of patients with chronic stable coronary heart disease.

Simultaneous quantitation of nicorandil and its denitrated metabolite in plasma by LC-MS/MS: application for a pharmacokinetic study.

A liquid chromatography-electrospray ionization tandem mass spectrometry method was developed and validated for the simultaneous quantitation of nicorandil and its denitrated metabolite, N-(2-hydroxyethyl)-nicotinamide, in rat plasma. After a liquid-liquid extraction step, chromatographic separation was performed on a ShinPack C(18) column with an isocratic mobile phase composed of methanol and 2 mM aqueous ammonium acetate containing 0.03% (v/v) formic acid (33:67 v/v). Procainamide was used as an internal standard (IS). Selected reaction monitoring was performed using the transitions m/z 212 → m/z 135, m/z 166 → m/z 106 and m/z 236 → m/z 163 to quantify nicorandil, its denitrated metabolite and IS, respectively. Calibration curves were constructed over the range of 5-15,000 ng.ml(-1) for both nicorandil and its metabolite. The mean relative standard deviation (RSD%) values for the intra-run precision were 5.4% and 7.3% and for the inter-run precision were 8.5% and 7.3% for nicorandil and its metabolite, respectively. The mean accuracy values were 100% and 95% for nicorandil and its metabolite, respectively. No matrix effect was detected in the samples. The validated method was successfully applied to a pharmacokinetic study after per os administration of nicorandil in rats.

Usefulness of rat skin as a substitute for human skin in the in vitro skin permeation study.

Sprague-Dawley (SD) rats are broadly used in preclinical studies for drug development, so a lot of information for the rats can be obtained especially from pharmacokinetic, pharmacological and toxicological studies. The purpose of this study was to clarify whether SD rat skin can be used to predict human skin permeability. In vitro permeation studies of the three model drugs, nicorandil, isosorbide dinitrate, and flurbiprofen, through human skin and SD rat skin were performed using Franz-type diffusion cells. The permeation rates of the three model drugs through human skin and SD rat skin were determined, and their variations were evaluated. The inter-individual variations in SD rat skin permeability of the three model drugs were much lower than that in human skin permeability, although the permeation rates of the three model drugs through the SD rat skin were about twice those through human skin. In addition, no difference in the skin permeability coefficients of the three model drugs was obtained between fresh SD rat skin and frozen SD rat skin. The markedly smaller variation in the permeability through SD rat skin compared with that through human skin indicated that in vitro permeation studies using SD rat skin would be especially useful for evaluating differences in the skin permeability of the three model drugs as well as for predicting human skin permeability.

Variation assessment for in vitro permeabilities through Yucatan micropig skin.

The purpose of this study was to evaluate the variations in the in vitro Yucatan micropig (YMP) skin permeabilities of drugs and to clarify whether YMP skin can be used to predict human skin permeability. In vitro permeation studies of the three model drugs, nicorandil, isosorbide dinitrate and flurbiprofen, through YMP skin were performed using Franz-type diffusion cells. The permeation rates of the three model drugs were determined, and their variations were evaluated. The inter-individual variations in YMP skin permeability for the three model drugs were smaller than that in human skin permeability, and the permeation rates of the three model drugs through the YMP skin were approximately half that through human skin. In addition, the intra-individual variations in YMP skin permeability for nicorandil and flurbiprofen were much smaller than the inter-individual variations in YMP skin. The inter- and intra-regional variations in YMP skin permeability were very small. The markedly smaller variation in the permeability through YMP skin as compared with that through human skin indicated that in vitro permeation studies using YMP skin would be particularly useful for evaluating differences in the skin permeability of the three model drugs as well as for predicting human skin permeability.

Pharmacokinetics of nicorandil in dogs with mild mitral regurgitation.

The aim of this study was to examine the pharmacokinetics of nicorandil, a hybrid of an adenosine triphosphate-sensitive potassium channel opener and a nitrate, and to estimate its clinical doses in dogs with mild mitral valve regurgitation (MR). Nicorandil (0.1, 0.3, and 1.0 mg/kg) was administered orally to normal dogs and those with experimentally-induced MR, and its plasma concentrations were analyzed using high-performance liquid chromatography. Plasma concentrations increased dose-dependently after the administration of nicorandil, and were not different between normal dogs and those with MR. Similar to the effective plasma values obtained in cardiac disease in humans, the findings of this pharmacokinetic study may indicate that a dose of 0.3-1.0 mg/kg has the same effectiveness in dogs with cardiac dysfunction.

Population pharmacokinetic and pharmacodynamic modelling of the effects of nicorandil in the treatment of acute heart failure.

AIMS: The aims of the study were 1) to evaluate the pharmacokinetics of nicorandil in healthy subjects and acute heart failure (AHF) patients and 2) to evaluate the exposure-response relationship with pulmonary arterial wedge pressure (PAWP) in AHF patients and to predict an appropriate dosing regimen for nicorandil. METHODS: Based on the data from two healthy volunteer and three AHF patient studies, models were developed to characterize the pharmacokinetics and pharmacodynamics of nicorandil. PAWP was used as the pharmacodynamic variable. An asymptotic exponential disease progression model was used to account for time dependent changes in PAWP that were not explained by nicorandil exposure. The modelling was performed using NONMEM version V. RESULTS: The pharmacokinetics of nicorandil were characterized by a two-compartment model with linear elimination. CL, V1 and V2 in AHF patients were 1.96, 1.39 and 4.06 times greater than in healthy subjects. Predicted plasma concentrations were assumed to have an immediate concentration effect relationship on PAWP. An inhibitory E(max) model with E(max) of -11.7 mmHg and EC(50) of 423 microg l(-1) was considered the best relationship between nicorandil concentrations and PAWP. PAWP decreased independently of nicorandil exposure. This drug independent decline was described by an asymptotic decrease of 6.1 mmHg with a half-life of 5.3 h. CONCLUSIONS: AHF patients have higher clearance and initial distribution volume of nicorandil compared with healthy subjects. The median target nicorandil concentration to decrease PAWP by 30% is predicted to be 748 microg l(-1), indicating that a loading dose of 200 microg kg(-1) and a maintenance dose of 400 microg kg(-1) h(-1) would be appropriate for the initial treatment of AHF.

Design and in vitro/in vivo evaluation of novel nicorandil extended release matrix tablets based on hydrophilic interpolymer complexes and a hydrophobic waxy polymer.

The purpose of this work was to develop an extended release matrix tablet of nicorandil; a freely water soluble drug used in cardiovascular diseases. Chitosan (CH)/hyaluronate sodium (HA), pectin (PE) or alginate sodium (AL) interpolymer complexes (IPCs) were prepared. The optimum IPCs (CH:HA, 40:60), (CH:PE, 30:70) and (CH:AL, 20:80) were characterized by Fourier transform infrared spectroscopy. The IPCs were based on electrostatic interactions between protonated amine groups of CH and carboxylate groups of HA, PE or AL. Nicorandil matrix tablets were prepared using the optimum IPCs, alone or in combination with Imwitor 900 K. Evaluations such as weight variation, thickness, content uniformity, friability, disintegration and in vitro release studies were performed. The tablets showed acceptable pharmacotechnical properties and complied with compendial requirements. Results of the dissolution studies revealed that formula F11 (CH:AL, 20:80) IPC:Imwitor 900 K, 3:1) could extend drug release > 8h. Most formulae exhibited non-Fickian diffusion drug release profiles. When compared to the immediate release Ikorel tablet, the duration of effective nicorandil therapeutic concentration from formula F11, in healthy human volunteers, was significantly (P<0.05) extended from 4 to 8 h with expected lowering in side effects potential.

An estimation method of the half-life for a one-compartment model of a single bolus intravenous injection by a single sampling.

In clinical trials, sometimes only a single drug concentration can be measured from a patient because of the patient's burden. In this case, the sampling point is usually identical for all patients. From a single concentration, we cannot generally obtain point-estimates of each pharmacokinetic parameter. In this paper, we propose a method to estimate the half-life of a one-compartment model of a single bolus intravenous injection from a single concentration at a sampling point of or after three half-lives. We analytically show that the later the sampling point is the better estimate of the half-life we can get. This approach is illustrated by simulated concentration-data and nicorandil concentration-data. Therefore, we compared the performance of the proposed method with that of the Bayesian approach.

Effect of nerodilol and carvone on in vitro permeation of nicorandil across rat epidermal membrane.

The objective of the study was to investigate the effect of nerodilol and carvone on the in vitro transdermal delivery of nicorandil so as to fabricate a membrane-moderated transdermal therapeutic system. The in vitro permeation studies were carried across the rat epidermal membrane from the hydroxypropyl methylcellulose (HPMC) gels (prepared with 70:30 v/v ethanol-water) containing selected concentrations of a terpene such as nerodilol (0%w/w, 4%w/w, 8%w/w, 10%w/w, or 12%w/w) or carvone (0%w/w, 4%w/w, 8%w/w, 12%w/w, or 16%w/w). The amount of nicorandil permeated (Q(24)) from HPMC gel drug reservoir without a terpene was 3424.6+/-51.4 microg/cm(2), and the corresponding flux of the drug was 145.5+/-2.2 microg/cm(2). h. The flux of nicorandil increased with an increase in terpene concentration in HPMC gel. It was increased ranging from 254.9+/-3.1 to 375.7+/-3.2 microg/cm(2).h or 207.6+/-4.7 to 356.7+/-15.3 microg/cm(2). h from HPMC gels containing nerodilol (4%w/w to 12%w/w) or carvone (4%w/w to 16%w/w), respectively. Nerodilol increased the flux of nicorandil by about 2.62-folds whereas carvone increased the flux of the drug by about 2.49-folds across the rat epidermal membrane. The results of the Fourier Transform Infrared (FT-IR) study indicated that the enhanced in vitro transdermal delivery of nicorandil might be due to the partial extraction of stratum corneum lipids by nerodilol or carvone. It was concluded that the terpenes, nerodilol and carvone, produced a marked penetration enhancing effect on the transdermal delivery of nicorandil that could be used in the fabrication of membrane-moderated transdermal therapeutic systems.

Controlled in vivo release of nicorandil from a carvone-based transdermal therapeutic system in human volunteers.

The aim of our present study was to prepare and evaluate a carvone-based transdermal therapeutic system (TTS) of nicorandil to find its ability in providing the desired in vivo controlled release profile on dermal application to human volunteers. The effect of EVA 2825, and adhesive-coated EVA 2825, and adhesive-coated EVA 2825-rat skin composite on the in vitro permeation of nicorandil from a carvone-based HPMC gel drug reservoir was studied against a control (rat abdominal skin alone). The carvone-based drug reservoir system was sandwiched between adhesive-coated EVA 2825-release liner composite and a backing membrane. The resultant drug reservoir sandwich was heat-sealed to produce a circle-shaped TTS (20 cm(2)) that was subjected to in vivo evaluation on dermal application to human volunteers against oral administration of immediate-release tablets of nicorandil. The carvone-based TTS provided a steady-state plasma concentration of 20.5 ng/ml for approximately 24 hr in human volunteers. We concluded that the carvone-based TTS of nicorandil provided the desired in vivo controlled-release profile of the drug for the predetermined period of time.

In vivo evaluation of limonene-based transdermal therapeutic system of nicorandil in healthy human volunteers.

Hydroxypropyl methylcellulose (HPMC) gel drug reservoir system prepared with 70:30 v/v ethanol-water solvent system containing 6% w/w of limonene was effective in promoting the in vitro transdermal delivery of nicorandil. The objective of the present study was to fabricate and evaluate a limonene-based transdermal therapeutic system (TTS) for its ability to provide the desired steady-state plasma concentration of nicorandil in human volunteers. The in vitro permeation of nicorandil from a limonene-based HPMC gel drug reservoir was studied across excised rat skin (control), EVA2825 membrane, adhesive-coated EVA2825 membrane and adhesive-coated EVA2825 membrane-excised rat skin composite to account for their effect on the desired flux of nicorandil. The flux of nicorandil from the limonene-based HMPC drug reservoir across EVA2825 membrane decreased to 215.8 +/- 9.7 microg/cm(2).h when compared to that obtained from control, indicating that EVA2825 was effective as a rate-controlling membrane. The further decrease in nicorandil flux across adhesive-coated EVA2825 membrane and adhesive-coated EVA2825 membrane-excised rat skin composite showed that the adhesive coat and skin also controlled the in vitro transdermal delivery. The limonene-based drug reservoir was sandwiched between adhesive-coated EVA2825-release liner composite and a backing membrane. The resultant sandwich was heat-sealed as circle-shaped patch (20 cm(2)), trimmed and subjected to in vivo evaluation in human volunteers against immediate-release tablets of nicorandil (reference formulation). The fabricated limonene-based TTS of nicorandil provided a steady-state plasma concentration of 21.3 ng/ml up to 24 h in healthy human volunteers. It was concluded that the limonene-based TTS of nicorandil provided the desired plasma concentration of the drug for the predetermined period of time with minimal fluctuations and improved bioavailability.

Bioavailability of nerodilol-based transdermal therapeutic system of nicorandil in human volunteers.

The objective of the present investigation was to design and evaluate a nerodilol-based transdermal therapeutic system (TTS) for finding its ability in providing the desired steady-state plasma concentration of nicorandil in human volunteers. The influence of EVA2825 membrane, adhesive-coated EVA2825 membrane and adhesive-coated EVA2825-rat skin composite on the in vitro permeation of nicorandil from a nerodilol-based HPMC gel drug reservoir was studied against a control (excised rat skin alone). The flux of nicorandil from the nerodilol-based HMPC drug reservoir across excised rat skin (control) was 384.0+/-4.6 microg/cm2 h and this decreased to 222.7+/-7.1 microg/cm2 h when studied across EVA2825 membrane indicating that EVA2825 membrane was effective as rate controlling membrane. The flux of the drug decreased to 183.8+/-5.7 microg/cm2 h on application of a water-based acrylic adhesive (TACKWHITE A 4MED) coat to EVA2825 membrane. However, the flux of nicorandil across adhesive-coated EVA2825-membrane-rat-skin composite was 164.8+/-1.8 microg/cm2 h, which was 1.74-times of the required flux that prompted for preparation of TTS. The nerodilol-based drug reservoir system was sandwiched between a composite of adhesive-coated EVA2825 membrane-release liner and a backing membrane. The resultant sandwich was heat-sealed to produce circle-shaped TTS (20 cm2) that were subjected to bioavailability study in human volunteers against immediate release nicorandil tablet. The nerodilol-based TTS provided a steady-state plasma concentration of 25.5 ng/ml for 24 h in human volunteers. It was concluded that the nerodilol-based TTS of nicorandil provided the desired plasma concentration of the drug for the predetermined period of time with minimal fluctuations.

Cardiomyocyte mitochondrial KATP channels participate in the antiarrhythmic and antiinfarct effects of KATP activators during ischemia and reperfusion in an intact anesthetized rabbit model.

Recent evidence suggests that the mitochondrial K(ATP) channels may be involved as a subcellular mediator in cardioprotection afforded by ischemic and pharmacological preconditioning by K(ATP) activators. The present study investigated the effects of administration of non-hypotensive doses of ATP-sensitive K(+) channel (K(ATP)) openers, nicorandil (NIC) and pinacidil (PIN), and specific blockers of mitochondrial (5-hydroxydecanoate) and sarcolemmal (1-[5-[2-(5-chloro-o-anisamido)ethyl]-2-methoxyphenyl]sulfonyl-3-methyl-thiourea, HMR 1883) K(ATP) channels prior to and during coronary occlusion and post-ischemic reperfusion on survival rate, ischemia- and reperfusion-induced arrhythmias and myocardial infarct size in anesthetized rabbits. In Group I, myocardial ischemia-induced arrhythmias were provoked by tightening a ligature over the left main coronary artery for 30 min. In Group II, arrhythmias were induced by reperfusion following a 20 min ligation of the same artery. Both in Group I and Group II, early iv administration of NIC (0.47 mg/kg), PIN (0.1 mg/kg), HMR 1883 (3 mg/kg)/NIC and HMR 1883/PIN just prior to and during ischemia increased survival rate (75%, 86%, 75% and 75%, respectively, vs. 55% in the control in Group I; 75%, 75%, 75% and 67%, respectively, vs. 50% in the control in Group II), significantly decreased the incidence and severity of life-threatening arrhythmias and significantly decreased myocardial infarct size. However, late iv administration of NIC or PIN just prior to reperfusion did not increase survival rate nor confer any antiarrhythmic or cardioprotective effects. The antiarrhythmic and cardioprotective effects were abolished by pretreating rabbits with 5-hydroxy-decanoate (5 mg/kg, iv bolus). In the present study, higher levels of malondialdehyde and lower levels of reduced glutathione and superoxide dismutase in necrotic zone of myocardium in all subgroups in Group II suggest little anti-free radical property of NIC and PIN. Therefore, it may be assumed that mitochondrial K(ATP) channel opening leads to mitochondrial generation and release of ROS providing for IPC and antiarrhythmic activity. The mitochondrial rather than sarcolemmal K(ATP) channel may represent a potential site of cardioprotection and antiarrhythmic activity.