Isosorbide 5-mononitrate: a review of a sustained-release formulation (Imdur) in stable angina pectoris

Obtaining and Characterization of a Polydisperse System Used as a Transmembrane Carrier for Isosorbide Derivatives

Due to their effect of vasodilatation, isosorbide nitrates represent one of the most important and most used solutions for angina pectoris. Unfortunately, these compounds have multiple dose-related adverse drug reactions such as headache, weakness, mild dizziness, and occasionally heart rate changes, nausea, vomiting, and sweating. The main aims of this research were to obtain and to evaluate new polyurethane (PU) structures that can be used as a proper transmembrane carrier with an improved release kinetic. Chitosan-based PU structures were obtained by a polyaddition process between hexamethylene diisocyanate and a mixture of chitosan, butanediol, and polyethylene glycol in the presence of caffeine as a synthesis catalyst. The obtained samples (with and without isosorbide nitrates) were characterized regarding the encapsulation and release rate (UV-Vis spectra), chemical composition (FTIR), thermal stability (thermal analysis), morphology changes (SEM and SANS), and in vivo irritation tests. These methods revealed no significant differences between the two sample structures. Multipopulational structures with sizes between 73 and 310 nm, with an increased tendency to form clusters and a high resistance to heat (up to 280°C), were obtained. This study presents an alternative administration of isosorbide derivatives based on a PU carrier with a high biocompatibility and a prolonged release.

In Vitro-In Vivo Predictive Dissolution-Permeation-Absorption Dynamics of Highly Permeable Drug Extended-Release Tablets via Drug Dissolution/Absorption Simulating System and pH Alteration

Each of dissolution and permeation may be a rate-limiting factor in the absorption of oral drug delivery. But the current dissolution test rarely took into consideration of the permeation property. Drug dissolution/absorption simulating system (DDASS) valuably gave an insight into the combination of drug dissolution and permeation processes happening in human gastrointestinal tract. The simulated gastric/intestinal fluid of DDASS was improved in this study to realize the influence of dynamic pH change on the complete oral dosage form. To assess the effectiveness of DDASS, six high-permeability drugs were chosen as model drugs, including theophylline (pK_a1 = 3.50, pK_a2 = 8.60), diclofenac (pK_a = 4.15), isosorbide 5-mononitrate (pK_a = 7.00), sinomenine (pK_a = 7.98), alfuzosin (pK_a = 8.13), and metoprolol (pK_a = 9.70). A general elution and permeation relationship of their commercially available extended-release tablets was assessed as well as the relationship between the cumulative permeation and the apparent permeability. The correlations between DDASS elution and USP apparatus 2 (USP2) dissolution and also between DDASS permeation and beagle dog absorption were developed to estimate the predictability of DDASS. As a result, the common elution-dissolution relationship was established regardless of some variance in the characteristic behavior between DDASS and USP2 for drugs dependent on the pH for dissolution. Level A in vitro-in vivo correlation between DDASS permeation and dog absorption was developed for drugs with different pKa. The improved DDASS will be a promising tool to provide a screening method on the predictive dissolution-permeation-absorption dynamics of solid drug dosage forms in the early-phase formulation development.

Synthesis of biosafe isosorbide dicaprylate ester plasticizer by lipase in a solvent-free system and its sub-chronic toxicity in mice

The biosafety isosorbide dicaprylate ester plasticizer was synthesized with bubbling dried air in solvent-free system.

Oral misoprostol and vaginal isosorbide mononitrate for labor induction: a randomized controlled trial

OBJECTIVE

To estimate whether vaginal isosorbide mononitrate, added to oral misoprostol for cervical ripening and labor induction, shortens time to vaginal delivery.

METHODS

A prospective, randomized trial was conducted. Women scheduled for labor induction between 32 and 42 weeks and with unfavorable cervices (modified Bishop score 6 or lower) were randomized to receive oral misoprostol every 4 hours, up to four doses, with or without isosorbide mononitrate every 6 hours, up to two doses. A strict protocol was used, including timing of oxytocin use and amniotomy. Side effects were assessed 6 hours after study initiation. One hundred forty-two patients were required to detect a change in time to vaginal delivery of 4 hours (alpha=.05 and beta=.20). Data were analyzed by intent to treat. Student's t, chi square, Fisher's exact, and Mann-Whitney tests were used where appropriate with P< or =.05 deemed significant.

RESULTS

One hundred fifty-six women were randomized; three were excluded after randomization. Seventy-eight women received misoprostol, and 78 received misoprostol with isosorbide mononitrate. Demographic characteristics were similar between groups. The time to vaginal delivery was not reduced when isosorbide mononitrate was added to misoprostol. Cesarean delivery rates and contraction and fetal heart rate abnormalities were similar between groups. Side effects were also similar between groups, except that women given isosorbide mononitrate experienced headaches more often. Neonatal outcomes were similar between groups.

CONCLUSION

The addition of vaginal isosorbide mononitrate to oral misoprostol for cervical ripening and labor induction did not reduce time to vaginal delivery and was associated with a greater incidence of headache.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00374621.

LEVEL OF EVIDENCE

I.

Dual effect of nitrate therapy for cyclosporine-induced hypertension on vascular and platelet morphofunctional markers; an animal model

The present study sought to evaluate the prevention and reversion effects of isosorbide-5-mononitrate (Is-5-Mn) on the development of hypertension (HT) and on the underlying vascular and platelet morphofunctional disturbances, using an animal model of cyclosporine (CsA)-induced HT. The following rat groups (n = 8) were tested: (1) a control group (orange juice, for 7 weeks); (2) the CsA group (5 mg/kg/d for 7 weeks); (3) the Is-5-Mn group (150 mg/kg/d, twice a day for 7 weeks); (4) the prevention group (Is-5-Mn + CsA) treated for 2 weeks with Is-5-Mn only and thereafter with both drugs for 7 weeks; (5) the curative group (CsA + Is-5-Mn) beginning 7 weeks after CsA and following thereafter with both drugs for 5 weeks. Blood pressure, lipid profile, vascular lesion, platelet aggregation and morphology, and platelet thromboxane A(2)/vascular prostacyclin equilibrium were evaluated. Is-5-Mn + CsA therapy prevented (systolic blood pressure [SBP]: 114.3 +/- 1.9 mm Hg, P < .001; diastolic blood pressure [DBP]: 97.0 +/- 3.3 mm Hg, P < .001) the CsA-induced HT (SBP: 146.2 +/- 4.5 mm Hg, P < .001; DBP: 124.9 +/- 4.5 mm Hg, P < .001 vs control: SBP: 111.6 +/- 0.7 mm Hg; DBP: 94.6 +/- 1.0 mm Hg), as well as the vascular lesion and the platelet morphofunctional disturbances. The curative group did not show attenuated CsA-induced BP increase; it showed further enhancement of the HT effect (SBP: 159.7 +/- 5.5 mm Hg, P < .05; DBP: 132.8 +/- 2.8 mm Hg), as well as worsened vascular lesions and platelet function, namely a disruption in the TXA(2)/PGI(2) equilibrium. Our data suggested that Is-5-Mn therapy may be a valid choice to prevent the morphofunctional changes associated with CsA-induced HT, when used as a preventive therapy. A careful evaluation of the impact of nitrate therapy should be considered, particularly the negative effect on cardiovascular hemodynamics, when considering its use after previous CsA disturbances have been established.

Once daily therapy with isosorbide-5-mononitrate causes endothelial dysfunction in humans: evidence of a free-radical-mediated mechanism

OBJECTIVES

The aim of the study was to determine if isosorbide-5-mononitrate (IS-5-MN) 120 mg, taken once daily for 7 days, is associated with evidence of endothelial dysfunction and whether this effect is determined by increased free radical production.

BACKGROUND

Tolerance to nitroglycerin is associated with increased free radical production and abnormal endothelial function. To date, no data is available concerning the effect of IS-5-MN, administered in clinically employed dosages, on endothelial function in humans.

METHODS

A total of 19 healthy volunteers were randomized in a double-blind fashion to therapy with IS-5-MN (120 mg once daily) or placebo. After 7 days of treatment, forearm blood flow responses to acetylcholine (Ach; 7.5, 15, and 30 microg/min) and N-monomethyl-L-arginine (L-NMMA; 1, 2, and 4 mumol/min) were measured. In a separate study, after 7 days of therapy with IS-5-MN 120 mg once daily, the responses to Ach were assessed during intra-arterial coinfusion of vitamin C (24 mg/min) or saline.

RESULTS

As compared with placebo, IS-5-MN caused significant blunting of the responses to both Ach (peak responses: placebo 127 +/- 31%; IS-5-MN 52 +/- 24%) and L-NMMA (peak responses: placebo 41 +/- 5%; IS-5-MN 22 +/- 8%). Vitamin C completely restored the forearm blood flow responses to Ach (peak responses: vitamin C 180 +/- 33%; saline 107 +/- 17%).

CONCLUSIONS

We document for the first time that IS-5-MN impairs endothelial function in humans in vivo. Suggesting a role of oxygen free radicals, nitrate-induced abnormalities in endothelium-dependent vasomotor responses were reversed by the antioxidant vitamin C.

Isosorbide-5-mononitrate treatment prevents cyclosporin A-induced platelet hyperactivation and the underlying nitric oxide-cyclic guanosine-3',5'-monophosphate disturbances

INTRODUCTION

The clinical use of cyclosporin A (CsA) is commonly associated with the development of hypertension and increased risk of thromboembolic events. Decreased endothelium-dependent relaxation and increased platelet activation seems to be involved on those side effects, but the underlying mechanisms are not yet elucidated. The present study aimed to evaluate the CsA effect on the platelet NO-cyclic guanosine-3',5'-monophosphate (cGMP) pathway and the putative benefits of concomitant isosorbide-5-mononitrate (IS-5-MN) administration on CsA-induced hypertension and on platelet hyperactivation.

MATERIALS AND METHODS

Blood pressures, platelet NO synthase activity and cGMP content, intracellular free calcium concentration ([Ca2+]i) and whole blood platelet aggregation were assessed in three rat groups orally treated, during 7 weeks, with the following diets: orange juice (control group), 5 mg/kg/day of CsA (CsA group) and 150 mg/kg/day, b.i.d., of IS-5-MN for 2 weeks and IS-5-MN plus 5 mg/kg/day of CsA for 7 weeks (IS-5-MN+CsA group).

RESULTS

IS-5-MN treatment has prevented hypertension development obtained in the solely CsA-treated rats. CsA treatment has inhibited NOS activity, which was reverted by the concomitant IS-5-MN and CsA administration. On the contrary, platelets from CsA-treated rats had cGMP content increased when compared with the control rats. The variation obtained when ISMN was present was less predominant. Therefore, the organic nitrate treatment has prevented platelet hyperactivation, namely, by decreasing thrombin-evoked [Ca2+]i and collagen-evoked platelet aggregation, when compared with the solely CsA-treated group. The preventive effect of IS-5-MN was reinforced by electron microscopy studies of platelet activation.

CONCLUSIONS

By increasing [Ca2+]i and aggregation, CsA induces platelet hyperactivation and simultaneously increases cGMP content, which might represent a compensatory inhibitory mechanism. The concomitant IS-5-MN treatment prevents the above-mentioned platelet hyperreactivity and tends to normalize the NO-cGMP pathway as well as the development of hypertension.

[Coronary artery disease observed in general hospitals: ETTIC study. Comparison between trimetazidine and mononitrate isosorbide for patients receiving betablockers]

The extended use of interventional surgery of revascularisation has modified the prognosis and the evolution of ischaemic heart diseases. However, both coronary artery bypass graft and percutaneous transluminal coronary angioplasty failed to make the symptomatic or subclinical ischaemic manifestations of chronic coronary insufficiency disappear. The interest of using betablockers as a first-line therapy was widely demonstrated. However, their combination with another efficient molecule is often necessary. The aim of this trial has been to appreciate the efficiency of the association of a betablocker with either trimetazidine or with isosorbide monoitrate. Hundred and eighty five patients retaining a positive effort test despite 100 mg of atenolol, received in addition, either 60 mg of trimetazidine (93 cases) of 60 mg of isosorbide mononitrate (92 cases) for a two-month period and are then re-evaluated at the end of this period. The ischaemic threshold is delayed in a significant way in both groups (p < 0.0001; trimetazidine +7%, isosorbide mononitrate +10.7%). Twenty-three percent of the exercise tests under trimetzidine and 19% under isosorbide mononitrate become negative after two months of the therapeutic combination. The clinical improvement is even clearer with the disappearance of the angina crisis during the week before the second exercise test in 63% of the cases under trimetazidine and 54% of the cases under isosorbide mononitrate, among the patients who had kept it under atenolol at the inclusion. In conclusion, the combination of a second efficient molecule, trimetazidine or isosorbide mononitrate, brings a functional and objective improvement to patients with insufficient chronic coronary disease not totally controlled using a betablocker, even with high dosage. One should notice two important advantages in favour of the trimetazidine: one is practical due to a better tolerance (lack of cephalalgia), the other is conceptual (use of the complementary metabolic approach of cellular oxygenation rather than the haemodynamic approach of nitrate compounds which are already in concurrency with all other anti-ischaemic molecules).

Effect of long-acting isosorbide-5-mononitrate administration on large artery distensibility in patients with essential hypertension

To evaluate the clinical efficacy of long-acting nitrates, isosorbide-5-mononitrate (IS-5-MN), on large artery distensibility in patients with essential hypertension. Large arterial distensibility was assessed by automatic noninvasive measurement of the carotid-femoral pulse wave velocity (PWV). Seventeen patients aged 62.53+/-7.94 years (mean+/-SD) with essential hypertension undering long-term antihypertensive therapy were studied in this trial. PWV was measured 2 weeks and 4 weeks after oral administration of IS-5-MN (30 mg once daily) with previous therapy. There was no significant difference in systolic blood pressure, diastolic blood pressure, pulse pressure or heart rate at 2 weeks and 4 weeks after treatment compared with baseline. The carotid-femoral PWV decreased significantly at 2 and 4 weeks after treatment (p<0.05, p< 0.05, respectively). Long-acting nitrates have potential value in improving large arterial distensibility in patients with essential hypertension independent of blood pressure alteration. It might be used as an effectively additive drug in hypertension control.

Acute and chronic effects of isosorbide-5-mononitrate administration on effective renal plasma flow and the renin-aldosterone system in cirrhotic patients

BACKGROUND AND AIMS

Isosorbide-5-mononitrate (ISMO) has been shown to be effective in reducing the risk of variceal bleeding in patients with cirrhosis. However, recent studies have suggested that this drug compromises renal function. The present study was conducted to assess the acute and chronic effects of ISMO on effective renal plasma flow (ERPF) and the renin-aldosterone profile in cirrhotic patients.

METHODS

Fifteen cirrhotic patients were included in the present study. The mean arterial pressure (MAP), heart rate (HR), serum renin concentration (SR), ERPF and plasma aldosterone concentration (PA) were checked before ISMO treatment (baseline study), after a single oral dose of 20 mg ISMO (acute effect study) and after 3 weeks of ISMO treatment (chronic effect study).

RESULTS

Our data showed that the oral administration of a single dose (20 mg) of ISMO to cirrhotic patients was associated with significant decreases in ERPF (from 405.18 to 369.06 mL/min) and MAP (from 93.26 to 86.40 mmHg), and increases in HR (from 65.53 to 70.06 beats/min), SR (from 24.15 to 54.41 pg/mL), and PA (from 105.1 to 148.7 pg/mL). However, no significant changes were observed in HR, MAP, PA, SR, or ERPF after 3 weeks of ISMO treatment when compared with the baseline study.

CONCLUSIONS

The administration of ISMO causes a decrease in ERPF in cirrhotic patients and its use in patients with renal impairment should be considered cautiously.