Effects of a new calcium antagonist, Rec 15/2375, on cardiac contractility of conscious rabbits

The solution, solid state stability and kinetic investigation in degradation studies of lercanidipine: study of excipients compatibility of lercanidipine

The objectives of this research were to evaluate the stability of lercanidipine in solution state and solid state and explore the compatibility of drug with oils, surfactants and cosurfactants as excipients. The effect of pH on the degradation in solution state was studied through pH-rate profile of lercanidipine in constant ionic strength buffer solutions in pH range 1-8 which gives the pH of maximum stability. Powdered lercanidipine was stored under 40°C/0%~75% relative humidities (RH) or 0% RH/5~50°C to study the influence of RH and temperature on the stability of lercanidipine in solid state. Binary mixtures of lercanidipine and different excipients were stored at 40°C/75% RH, 40°C and at room temperature for excipient compatibility evaluation. The degradation of lercanidipine at different pH appears to fit a typical first-order reaction, but in solid state, it does not fit any obvious reaction model. Moisture content and temperature both play important roles affecting the degradation rate. Lercanidipine exhibits good compatibility with surfactants, cosurfactants and oils as excipients under stressed conditions of different storage temperature in a 3-week screening study. Moreover, the proposed high-performance liquid chromatography method was utilized to investigate the kinetics of the acidic and alkaline degradation processes of lercanidipine at different temperatures.

Preclinical cardiac safety assessment of drugs

The heart is a frequent site of toxicity of pharmaceutical compounds in humans, and when developing a new drug it is critical to conduct a thorough preclinical evaluation of its possible adverse effects on cardiac structure and function. Changes in cardiac morphology such as myocardial necrosis, hypertrophy or valvulopathy are assessed in regulatory toxicity studies in laboratory animals, although specific models may be needed for a more accurate detection of the risk. The potential proarrhythmic risk of new drugs is a major subject of concern and needs to be fully addressed before treatment of volunteers or patients takes place. In vitro assays are conducted to determine the effects on cardiac ion channels, in particular I(Kr) potassium channel antagonism. Prolongation of the QT interval is assessed in vivo, generally in telemetered dogs. Together, these two tests are considered to detect most arrhythmic drugs. The results of this core battery can be refined by additional studies, in particular assays on isolated cardiac tissues determining changes in cardiac action potential duration, shape and variability over time. Triggering of arrhythmia is assessed in hypokalaemic dogs with artificially created bradycardia, or in vitro in isolated whole hearts. The proarrhythmic risk of the new compound is then evaluated by integrating the results of these different tests. Drug adverse effects on cardiac electrophysiological function, in particular impulse formation and conduction, are evaluated through changes in ECG, generally recorded in dogs, pigs or monkeys. Changes in cardiac contractility occurring either as a primary effect of the drug on cardiac function or as a consequence of cardiac lesions should also be carefully assessed. In telemetered or anaesthetised animals, cardiac contractility is evaluated by measurement of left ventricular pressure and its first derivative over time. Echocardiography allows non-invasive measurement of drug-induced changes in ventricular wall movements and cardiac haemodynamics indicative of effects on contractility. In conclusion, a reliable and accurate evaluation of the cardiac safety of a new pharmaceutical agent is based on the results of in vitro tests, with overall moderate to high throughput, and in vivo experiments assessing the effects of the drug on the heart in its physiological environment. The specific sensitivities of the animals used in these assays to cardiac adverse effects should also be considered. The final evaluation of the cardiac risk is therefore based on an integrated analysis of the results from a battery of tests.

Rizatriptan in the treatment of migraine

Migraine is a common, disabling disorder associated with considerable personal and societal burden. Current guidelines recommend triptans for the acute treatment of migraine unlikely to respond to less effective therapies. Rizatriptan is a second-generation triptan available in tablet or orally disintegrating tablet (wafer) formulations that offers several advantages over other members of its class. Rizatriptan is rapidly absorbed from the gastrointestinal tract and achieves maximum plasma concentrations more quickly than other triptans, providing rapid pain relief. Clinical trials have shown that rizatriptan is at least as effective or superior to other oral migraine-specific agents in the acute treatment of migraine, and has more consistent long-term efficacy across multiple migraine attacks. Rizatriptan has a favorable tolerability profile, and patients have reported greater satisfaction and a preference for rizatriptan over other migraine-specific agents. Improvements in quality of life reported with rizatriptan are consistent with its favorable efficacy and tolerability profiles. Notably, multi-attribute decision models that combine clinical data with patient- and physician-reported treatment preferences have identified rizatriptan as one of three triptans closest to a hypothetical "ideal". The efficacy and tolerability of rizatriptan for the acute treatment of migraine have thus been well established.

Lercanidipine: a novel lipophilic dihydropyridine calcium antagonist with long duration of action and high vascular selectivity

Lercanidipine is a new 1,4-dihydropyridine derivative with potent, long-lasting and vascular-selective calcium entry blocking activity. Animal models of hypertension have shown lercanidipine to be potent, with a slow rate of onset and long lasting action and to have minimal or no effects on cardiac contractility. There was no evidence of tolerance after repeated oral treatment, and no effects were found on the autonomic nervous, central nervous, gastrointestinal or respiratory systems at antihypertensive doses. In man, lercanidipine is well absorbed after oral administration, with peak plasma levels occurring approximately 1.5 - 3 h after dosing. The drug is subject to extensive hepatic first pass metabolism with an elimination half-life of 2 - 5 h. With a more sensitive method, a mean terminal elimination half-life of 8 - 10 h was defined. Despite this short plasma half-life the drug has a long duration of action, most likely due to the high lipophilicity of lercanidipine and its partitioning in to the lipid bilayer of cell membranes, followed by diffusion to the receptor binding site. The efficacy of lercanidipine has been established in extensive clinical trials with comparison to both placebo and standard well-established antihypertensive therapies. These trials confirmed the efficacy of lercanidipine and its long duration of action which renders it suitable for once daily administration. Tolerability was good in all studies: the adverse event profile was comparable to that of placebo at lower doses, with a low incidence of palpitations and ankle oedema. Lercanidipine is a recently introduced example of a lipophilic and vasoselective dihydropyridine calcium antagonist which is an effective antihypertensive drug with a slow onset and long duration of action; it is associated neither with reflex tachycardia nor cardio-depressant activity.

Lercanidipine : a review of its efficacy in the management of hypertension

Lercanidipine (Zanidip) is a vasoselective dihydropyridine calcium channel antagonist that causes systemic vasodilation by blocking the influx of calcium ions through L-type calcium channels in cell membranes. It is a highly lipophilic drug that exhibits a slower onset and longer duration of action than other calcium channel antagonists. Furthermore, lercanidipine may have antiatherogenic activity unrelated to its antihypertensive effect. In two large, nonblind, noncomparative studies involving approximately 16 000 patients with mild-to-moderate hypertension, systolic blood pressure (BP) [SBP] and diastolic BP (DBP) were significantly reduced after 12 weeks' treatment with lercanidipine 10-20 mg/day. Furthermore, in the largest study, 64% of patients were responders (DBP <90 mm Hg) after 12 weeks of treatment and an additional 32% had their BP normalised (BP <140/90 mm Hg). In comparative trials, lercanidipine 10-20 mg/day was as effective as nifedipine slow release (SR) 20-40 mg twice daily, amlodipine 10 mg/day, felodipine 10-20 mg/day, nifedipine gastrointestinal therapeutic system (GITS) 30-60 mg once daily or verapamil SR 240 mg/day at reducing SBP and DBP in patients with mild-to-moderate hypertension after 2-16 weeks of therapy. In addition, 4 weeks of lercanidipine therapy (10 mg/day) was as effective as captopril 25mg twice daily, atenolol 50 mg/day or hydrochlorothiazide 12.5 mg/day. Lercanidipine 5-30 mg/day effectively decreased BP in elderly patients (aged >60 years) with mild-to-moderate hypertension or isolated systolic hypertension to the same extent as amlodipine 5-10 mg/day, nifedipine GITS 30-60 mg/day or lacidipine 2-4 mg/day after 24-26 weeks of therapy. In addition, a limited number of studies suggest that lercanidipine may have antihypertensive efficacy in patients with severe or resistant hypertension, in hypertensive patients with type 2 diabetes mellitus and in postmenopausal women with mild-to-moderate essential hypertension. Lercanidipine is well tolerated, with most treatment-emergent events related to vasodilation. Common adverse events included headache, flushing and peripheral oedema. Importantly, the incidence of vasodilatory oedema was significantly lower in patients receiving lercanidipine than in those receiving some other calcium channel antagonists.

CONCLUSION

Once-daily lercanidipine is an effective and well tolerated antihypertensive agent in patients with mild-to-moderate hypertension.

De la première à la quatrième génération de dihydropyridines : vers une meilleure efficacité et une meilleure tolérance

Dihydropyridines are among the most widely used drugs for the management of cardiovascular disease. Introduced in the 1960s, dihydropyridines have undergone several changes to optimise their efficacy and safety. Four generations of dihydropyridines are now available. The first-generation (nicardipine) agents have proven efficacy against hypertension. However, because of their short duration and rapid onset of vasodilator action, these drugs were more likely to be associated with adverse effects. The pharmaceutical industry responded to this problem by designing slow-release preparations of the short-acting drugs. These new preparations (second generation) allowed better control of the therapeutic effect and a reduction in some adverse effects. Pharmacodynamic innovation with regard to the dihydropyridines began with the third-generation agents (amlodipine, nitrendipine). These drugs exhibit more stable pharmacokinetics, are less cardioselective and, consequently, well tolerated in patients with heart failure. Highly lipophilic dihydropyridines are now available (lercanidipine, lacidipine). These fourth-generation agents provide a real degree of therapeutic comfort in terms of stable activity, a reduction in adverse effects and a broad therapeutic spectrum, especially in myocardial ischaemia and potentially in congestive heart failure.

A selective HPLC method for determination of lercanidipine in tablets

An HPLC reversed phase method using both UV (356 nm) and electrochemical (1000 mV) detection was developed in order to determine lercanidipine in commercial tablets. Repeatability and reproducibility were adequate. For quantification we have used the calibration plot method for lercanidipine concentration ranging between 1 x 10(-5) and 1 x 10(-4) M. Also, the proposed method is sufficiently selective to distinguish the parent drug and the degradation products after hydrolysis, photolysis or chemical oxidation. Furthermore, the typical excipients included in the drug formulation (talc, lactose, cornstarch, microcrystalline cellulose, carboxymethylcellulose and magnesium stearate) do not interfere with the selectivity of the method. Finally, the proposed chromatographic method was successfully applied to the quantitative determination of lercanidipine in commercial tablets.

Lercanidipine: a novel dihydropyridine calcium-channel blocker

Calcium-channel blockers (CCBs) have been used for the treatment of hypertension for more than 20 years, and recent clinical trials support the efficacy and safety of long-acting dihydropyridine (DHP) CCBs for a wide spectrum of hypertensive patients, including diabetic hypertensive patients. DHP CCBs are effective agents overall and are particularly effective when used in combination with other agents. Lercanidipine is a novel DHP CCB effective for the treatment of mild-to-moderate hypertension. Compared with other DHP CCBs, lercanidipine has a molecular design that imparts greater solubility within the arterial cellular membrane bilayer, membrane-controlled kinetics, and a high cholesterol tolerance factor. These favorable membrane-controlled kinetics impart a gradual onset of vasodilation and a long duration of action. Further, the unique pharmacokinetic and pharmacodynamic properties of lercanidipine appear to contribute to its efficacy and favorable safety profile. In clinical trials in the treatment of mild-to-moderate hypertension, lercanidipine was administered at a starting dose of 10 mg once daily, and increased to 20 mg once daily for nonresponders. Studies have shown that lercanidipine has a 24-hour antihypertensive effect and causes no significant increase in heart rate. Lercanidipine has been shown to be effective in a wide range of hypertensive patients, including mild-to-moderate hypertension, severe hypertension, the elderly, and those with isolated systolic hypertension. It is associated with a low rate of adverse events. Because of its efficacy and favorable safety profile, lercanidipine has the potential to improve blood pressure control in a wide range of patients, including those who have not responded to, or who have been unable to tolerate, other antihypertensive agents.

Lercanidipine: a review of its use in hypertension

Lercanidipine is a vasoselective dihydropyridine calcium antagonist which causes systemic vasodilation by blocking the influx of calcium ions through L-type calcium channels in cell membranes. It is a highly lipophilic drug and as such has a slower onset and longer duration of action than a number of other calcium antagonists. Preclinical evidence suggests that lercanidipine has antiatherogenic potential and it may also protect against end-organ damage. In well controlled clinical studies, once daily administration of lercanidipine 10 or 20mg effectively reduced blood pressure (BP) compared with placebo in patients with mild to moderate hypertension without affecting heart rate. Response rate (percentage of patients with diastolic BP < or =90mm Hg or reduced by > or =10mm Hg from baseline) ranged from 50 to 66% with lercanidipine 10 mg/day and up to 86% with lercanidipine 20 mg/day. The drug had a long duration of action: clinical measurements for diastolic BP yielded a trough/peak ratio of >0.8 for both lercanidipine dosages in 1 study. Comparative trials, either published in full or as abstracts, found lercanidipine 10mg once daily for > or =4 weeks to be at least as effective as atenolol 50mg once daily, candesartan cilexetil 16 mg/day, captopril 25mg twice daily, enalapril 20 mg/day, hydrochlorothiazide 12.5mg once daily, irbesartan 150 mg/day and slow release nifedipine 20mg twice daily in patients with mild to moderate hypertension. In addition, lercanidipine 20 mg/day was as effective as amlodipine 10 mg/day. Lercanidipine is effective in the treatment of elderly patients (aged 60 to 85 years) with mild to moderate essential hypertension and in those with isolated systolic hypertension. In addition, monotherapy with lercanidipine 20 or 40 mg/day has shown efficacy in patients with severe hypertension, and add-on therapy helped control BP in a large proportion of patients with severe hypertension not responding sufficiently to beta-blockers, diuretics or ACE inhibitors. Unpublished data indicate that the drug reduces blood pressure in patients with type 2 (non-insulin-dependent) diabetes mellitus, without adversely affecting glucose homeostasis. Lercanidipine was well tolerated in clinical trials, with most treatment-related adverse events typical of dihydropyridine calcium antagonists, namely headache, flushing, dizziness and ankle oedema.

CONCLUSIONS

Lercanidipine is an effective and well tolerated once daily antihypertensive agent in patients with mild to moderate hypertension. In addition, the drug may reduce BP when used as monotherapy in patients with severe hypertension or when used adjunctively in patients with resistant hypertension. Importantly, lercanidipine appears to be at least as effective and well tolerated as other commonly used antihypertensive agents. The drug therefore represents a useful therapeutic option in the management of patients with hypertension and will be particularly useful in patients not responding to, or intolerant of, antihypertensive agents from other drug classes.