Ranolazina en cardiopatía isquémica crónica: un factor protector frente a la fibrilación auricular de novo / Ranolazine in chronic ischaemic heart disease: a protective factor against de novo atrial fibrillation

Resumen Introducción: en pacientes con cardiopatía isquémica crónica, ranolazina se ha mostrado eficaz ante casos de angina. Estudios recientes la valoran como fármaco para prevenir la fibrilación auricular poscardioversión eléctrica, posquirúrgica o posinfarto. Objetivos: valorar la presencia a largo plazo de episodios de fibrilación auricular de novo en pacientes con cardiopatía isquémica crónica y nuevo episodio de angina inestable que inician ranolazina 350 o 500 mg/12 h, en comparación con el tratamiento habitual. Métodos: estudio observacional retrospectivo que compara la incidencia de fibrilación auricular de novo en 77 pacientes consecutivos, con diagnóstico de cardiopatía isquémica no revascularizable y nuevo ingreso por síndrome coronario agudo durante el año 2013, en comparación con los que iniciaron ranolazina frente a tratamiento convencional, en los 12 meses siguientes al evento. La detección de fibrilación auricular se basó en su presencia en un primer registro electrocardiográfico. Resultados: de 77 pacientes, 38 iniciaron ranolazina, sin diferencias en cuanto a las características basales de las dos poblaciones, con similares tasas de factores de riesgo cardiovascular clásicos, datos ecocardiográficos como tamaño auricular, o tratamiento previo empleado. Se observó una tasa de fibrilación auricular de novo del 5,3% en los pacientes tratados con ranolazina, frente al 23,1% en el grupo sin ranolazina (p<0,001). Al analizar el subgrupo de pacientes que presentó fibrilación auricular en su seguimiento, únicamente es significativa la no toma de ranolazina (p<0,001). Conclusión: el uso de ranolazina en pacientes con cardiopatía isquémica crónica no revascularizable podría suponer un efecto protector para el desarrollo de fibrilación auricular durante un seguimiento de al menos doce meses.

Abstract Introduction: Ranolazine has shown to be effective in cases of angina in patients with chronic ischaemic heart disease. Recent studies have evaluated it as a drug to prevent electrical post-cardioversion, post-surgical or post-infarction atrial fibrillation. Objectives: To perform a long-term evaluation of de novo atrial fibrillation episodes in patients with chronic ischaemic heart disease and a new episode of unstable angina that are taking 350 or 500 mg/12 h of ranolazine, in comparison with usual treatment. Methods: An observational, retrospective study was performed to compare the incidence of de novo atrial fibrillation in 77 consecutive patients with a diagnosis of non-revascularisable ischaemic heart disease and a new hospital admission due to acute coronary syndrome during the year 2013. These were compared with those that started with ranolazine and those on conventional treatment in the 12 months following the event. The detection of atrial fibrillation was based on its presence in a first electrocardiographic register. Results: Of the 77 patients, 38 were started on ranolazine, with no differences as regards the baseline characteristics of the two populations. They had similar rates of classic cardiovascular risk factors, echocardiographic data, such as atrial size, or previous treatment employed. A de novo atrial fibrillation rate of 5.3% was observed in the patients treated with ranolazine, compared to 23.1% in the non-ranolazine group (P<.001). On analysing the sub-group of patients that had an atrial fibrillation in their follow-up, only not taking of ranolazine was significant (P<.001). Conclusion: The use of ranolazine in patients with non-revascularisable ischaemic heart disease could have a protective effect against the development of atrial fibrillation during a 12 months follow-up.

Ações Transmurais Inotrópicas e Antiarrítmicas da Ranolazina em um Modelo Celular da Síndrome do QT Longo Tipo 3 / Inotropic and Antiarrhythmic Transmural Actions of Ranolazine in a Cellular Model of Type 3 Long QT Syndrome

Resumo A Ranolazina (RANO), conhecida na clínica como Ranexa, é um fármaco que previne a arritmia cardíaca através da inibição da corrente de sódio tardia (INaT). Um gradiente de voltagem transmural do canal Nav1.5 encontra-se na parede ventricular esquerda do coração. Assim, investigamos os efeitos da RANO em cardiomiócitos saudáveis e em modelo celular da Síndrome do QT longo tipo 3 (SQTL tipo 3). Usamos células isoladas do endocárdio (ENDO) e do epicárdio (EPI) e um software de medição com detecção de bordas por vídeo e microscopia de fluorescência para monitorar os transientes de cálcio. A RANO (0,1, 1, 10 e 30 uM, a 25OC) em uma série de frequências de estimulação teve impacto pouco significativo sobre ambos os tipos de células, mas a RANO (30uM) a 35OC minimizou o encurtamento dos sarcômeros em ~21% para células do endocárdio. Em seguida, para simular a SQTL tipo 3, as células do ENDO e EPI foram expostas à toxina ATX-II da anêmona do mar, que aumenta a INaT. As arritmias celulares induzidas por ATX-II foram suprimidas com o uso da RANO (30 µM) a 35OC. Com base nesses resultados, podemos concluir que a RANO tem um impacto pouco significativo sobre o encurtamento dos sarcômeros de células saudáveis do ENDO e EPI. Além disso, ela suprime as arritmias induzidas por INaT para níveis semelhantes nas células do ENDO e EPI.

Abstract Ranolazine (RANO) prevents cardiac arrhythmia by blocking the late sodium current (INaL). A transmural gradient of Nav1.5 is found in the left ventricular wall of the heart. Thus, we investigated the effects of RANO in healthy cardiomyocytes and in a cellular model of type 3 long QT syndrome (LQT3). We used isolated endocardium (ENDO) and epicardium (EPI) cells and a video edge detection system and fluorescence microscopy to monitor calcium transients. RANO (0.1, 1, 10 and 30 uM, at 25oC) at a range of pacing frequencies showed a minor impact on both cell types, but RANO at 30uM and 35oC for ENDO cells attenuated sarcomere shortening by~21%. Next, to mimic LQT3, we exposed ENDO and EPI cells to anemone toxin II (ATX-II), which augments INaL. Cellular arrhythmias induced by ATX-II were abrogated by RANO (30 µM) at 35oC. Based on our results we can conclude that RANO has a minor impact on sarcomere shortening of healthy ENDO and EPI cells and it abrogates arrhythmias induced by INaLto a similar level in ENDO and EPI cells.

Ranolazina como terapia antianginosa adicional en pacientes con enfermedad coronaria estable sintomática / Ranolazine as an additional antianginal therapy in patients with stable symptomatic coronary artery disease

INTRODUCCIÓN: La enfermedad coronaria estable posee varios tratamientos con beneficio probado tanto en mortalidad como en incidencia de eventos agudos. Sin embargo, el control de los síntomas, especialmente en aquellos que no responden a terapia de primera línea, sigue siendo controvertido. Este resumen pretende evaluar el papel de la ranolazina como terapia adicional al tratamiento antianginoso estándar en pacientes que persisten sintomáticos a pesar de éste. MÉTODOS: Para responder esta pregunta utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos cuatro revisiones sistemáticas que en conjunto incluyeron 16 estudios primarios, todos correspondientes a ensayos aleatorizados, de los cuales cuatro son atingentes para la pregunta específica. Concluimos que en pacientes con enfermedad coronaria estable que persisten sintomáticos a pesar de terapia antianginosa estándar, el tratamiento adicional con ranolazina podría disminuir los episodios de angina semanales pero aumentando la incidencia de efectos adversos, y resulta en poca o nula diferencia en el riesgo de muerte o infarto agudo al miocardio.

INTRODUCTION: There are several effective therapeutic alternatives for stable coronary artery, in terms of prevention of cardiovascular morbidity and mortality. However, the best way to achieve symptomatic control is a matter of debate, particularly in those who do not respond to first-line therapy. This summary aims to evaluate the role of ranolazine as an additional therapy to standard antianginal treatment in patients with persistent symptoms. METHODS: To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified four systematic reviews including 16 studies overall, all of which were randomized trials. We concluded additional treatment with ranolazine might decrease the frequency of anginal episodes but increase adverse effects. It probably has no effect on the risk of death or acute myocardial infarction.

Efficacy of ranolazine in lowering HbA1c in patients with type 2 diabetes mellitus: A meta-analysis

INTRODUCTION: Cardiovascular diseases and diabetes mellitus (DM) are two disease entities that commonly coexist in a single patient. Ranolazine is an active piperazine derivative approved by FDA in 2006 as an anti-anginal medication. It was noted to have HbA1c lowering effects in the trials on angina. The proposed mechanism of action is the inhibition of glucagon secretion by blocking the Na v1.3 isoform of sodium channels in pancreatic alpha cells leading to glucagon- and glucose-lowering effects. HbA1c lowering to a target of 6.5% in type 2 diabetes patients has been shown to reduce risk of microvascular complications. The objective of this study is to determine the efficacy and safety of Ranolazine in HbA1c lowering as an add-on therapy to existing anti-diabetic regimen. METHODS: A comprehensive literature search in PubMed, The Cochrane Central Register of Controlled Trials, the ClinicalTrials.gov website, Google Scholar databases and EMBASE databases were made using the search terms "Randomized controlled trial", "Ranolazine," "HbA1c," and "glycosylated hemoglobin", as well as various combinations of these, was done to identify randomized control trials. No restriction on language and time were done. The authors extracted data for characteristics, quality assessment and mean change in HbA1c after at least eight weeks of treatment with ranolazine. The program RevMan 5.3 was used to generate the statistical analysis of the data. RESULTS: Six RCTs were included to make up a total of 1,650 diabetic patients. Five studies had moderate risk of bias assessment while one had low risk of bias assessment and hence was not included in the analysis. The overall analysis showed an HbA1c reduction of 0.35% 0.68 to -0.03, p-value=0.03) however, the population was heterogenous (I2=100%). The heterogeneity was not eliminated by sensitivity analysis. DISCUSSION: The results showed a statistically significant lowering of HbA1c with ranolazine. However, the population was heterogenous. The sources of heterogeneity could be the (1) differences in the level of glycemic control among subjects as indicated by baseline HbA1c levels, (2) the current anti-diabetic regimen of the study patients, i.e. whether or not they are on insulin therapy, (3) the presence or absence of ischemic heart disease and (5) duration of ranolazine therapy, and (4) the presence or absence of chronic kidney disease. When the analysis excluded the population with combination insulin therapy and ranolazine, the effect becomes non-significant. Thus, the HbA1c lowering effect may have been from the insulin therapy rather than the ranolazine. CONCLUSION: Ranolazine as anti-diabetic therapy shows statistically significant HbA1c lowering effect. It can be a potential treatment option for patients with both DM and angina pectoris. However, well-designed, prospective trials are still recommended to determine the effect on a less heterogenous population. Likewise, more studies are needed to determine its safety.

Efficacy of ranolazine in lowering HbA1c in patients with type 2 diabetes mellitus: A meta-analysis

@#<p style="text-align: justify;"><strong>INTRODUCTION:</strong> Cardiovascular diseases and diabetes mellitus (DM) are two disease entities that commonly coexist in a single patient. Ranolazine is an active piperazine derivative approved by FDA in 2006 as an anti-anginal medication. It was noted to have HbA1c lowering effects in the trials on angina. The proposed mechanism of action is the inhibition of glucagon secretion by blocking the Na v1.3 isoform of sodium channels in pancreatic alpha cells leading to glucagon- and glucose-lowering effects. HbA1c lowering to a target of 6.5% in type 2 diabetes patients has been shown to reduce risk of microvascular complications. The objective of this study is to determine the efficacy and safety of Ranolazine in HbA1c lowering as an add-on therapy to existing anti-diabetic regimen.</p><p style="text-align: justify;"><strong>METHODS:</strong> A comprehensive literature search in PubMed, The Cochrane Central Register of Controlled Trials, the ClinicalTrials.gov website, Google Scholar databases and EMBASE databases were made using the search terms "Randomized controlled trial", "Ranolazine," "HbA1c," and "glycosylated hemoglobin", as well as various combinations of these, was done to identify randomized control trials. No restriction on language and time were done. The authors extracted data for characteristics, quality assessment and mean change in HbA1c after at least eight weeks of treatment with ranolazine. The program RevMan 5.3 was used to generate the statistical analysis of the data.</p><p style="text-align: justify;"><strong>RESULTS:</strong> Six RCTs were included to make up a total of 1,650 diabetic patients. Five studies had moderate risk of bias assessment while one had low risk of bias assessment and hence was not included in the analysis. The overall analysis showed an HbA1c reduction of 0.35% 0.68 to -0.03, p-value=0.03) however, the population was heterogenous (I2=100%). The heterogeneity was not eliminated by sensitivity analysis.</p><p style="text-align: justify;"><strong>DISCUSSION:</strong> The results showed a statistically significant lowering of HbA1c with ranolazine. However, the population was heterogenous. The sources of heterogeneity could be the (1) differences in the level of glycemic control among subjects as indicated by baseline HbA1c levels, (2) the current anti-diabetic regimen of the study patients, i.e. whether or not they are on insulin therapy, (3) the presence or absence of ischemic heart disease and (5) duration of ranolazine therapy, and (4) the presence or absence of chronic kidney disease. When the analysis excluded the population with combination insulin therapy and ranolazine, the effect becomes non-significant. Thus, the HbA1c lowering effect may have been from the insulin therapy rather than the ranolazine.</p><p style="text-align: justify;"><strong>CONCLUSION:</strong> Ranolazine as anti-diabetic therapy shows statistically significant HbA1c lowering effect. It can be a potential treatment option for patients with both DM and angina pectoris. However, well-designed, prospective trials are still recommended to determine the effect on a less heterogenous population. Likewise, more studies are needed to determine its safety.</p>

Nuevos enfoques farmacológicos en el manejo de la angina de pecho estable / New pharmacological approaches in the management of stable angina

RESUMEN En años recientes han sido introducidos nuevos antianginosos al mercado con mecanismos de acción novedosos, complementarios a los del arsenal farmacoterapéutico existente. Aunque el tratamiento de primera línea continúan siendo los betabloqueadores, antagonistas de canales de calcio y nitratos, el descubrimientos de nuevos aspectos fisiopatológicos de la enfermedad permitieron el desarrollo de blancos terapéuticos innovadores a nivel celular y molecular. El nicorandil, la trimetazidina, la ivabradina y la ranolazina se consideran nuevos fármacos antianginosos y constituyen la segunda línea de tratamiento de la angina de pecho estable; están indicados en pacientes que persisten sintomáticos a pesar del manejo de primera línea o en aquellos que presentan intolerancia o contraindicación a los betabloqueadores o antagonistas de canales de calcio. La trimetazidina, a través de su mecanismo de acción metabólico, mejora la tolerancia al ejercicio y puede ser útil en pacientes con falla cardíaca y contraindicación al uso de digitales; la ivabradina tiene un efecto cronotrópico negativo sin afectar el inotropismo ni la tensión arterial por lo que se puede usar en pacientes con taquiarritmias o falla cardíaca concomitante; en contraste, la ranolazina no afecta el cronotropismo por lo que se usa en pacientes con bradiarritmias aunque puede generar prolongación del intervalo QTc. La elección de alguno de estos medicamentos antianginosos de primera o segunda línea debe ser individualizado para cada paciente y se basa en las comorbilidades, contraindicaciones y preferencias del paciente. MÉD.UIS. 2016;29(3):79-93.

ABSTRACT In recent years, new antianginal agents with novel mechanisms of action have been launched to the market, as a complement to the existing therapeutic arsenal. Even though the beta-blockers, calcium channel blockers and nitrates continue to be the first line of treatment, recent discoveries of pathophysiological aspects of the disease led to the development of innovative therapeutic targets on both cellular and molecular level. Nicorandil, trimetazidine, ivabradine and ranolazine are novel antianginal drugs and constitute the second line of treatment of stable angina; these drugs are indicated for those patients who persist symptomatic despite treatment with first line agents or in those with contraindication or intolerance to beta-blockers o calcium channel blockers. Trimetazidine, through its metabolic mechanism of action, improves exercise tolerance and might be useful in patients with concomitant heart failure and contraindication to digitalis; ivabradine can be used in patients with concomitant tachyarrhythmias due to its negative chronotropic effect without affecting inotropism or blood pressure; in contrast, ranolazine doesn't affect chronotropism and can be used in patients with bradyarrhythmias, however, it might cause prolongation of the QTc interval. The choice of treatment with either of the first line or second line antianginal agents must be individualized for each patient and based on comorbidities, contraindications and patient's preference. MÉD.UIS. 2016;29(3):79-93.

Reduced immunoreactivities of B-type natriuretic peptide in pulmonary arterial hypertension rats after ranolazine treatment / 대한해부학회지

Pulmonary arterial hypertension (PAH) is a severe pulmonary vascular disease characterized by sustained increase in the pulmonary arterial pressure and excessive thickening and remodeling of the distal small pulmonary arteries. During disease progression, structural remodeling of the right ventricular (RV) impairs pump function, creates pro-arrhythmic substrates and triggers for arrhythmias. Notably, RV failure and lethal arrhythmias are major contributors to cardiac death in PAH that are not directly addressed by currently available therapies. Ranolazine (RAN) is an anti-anginal, anti-ischemic drug that has cardioprotective effects of heart dysfunction. RAN also has anti-arrhythmic effects due to inhibition of the late sodium current in cardiomyocytes. Therefore, we hypothesized that RAN could reduce the mal-adaptive structural remodeling of the RV, and prevent triggered ventricular arrhythmias in the monocrotaline-induced rat model of PAH. RAN reduced ventricular hypertrophy, reduced levels of B-type natriuretic peptide, and decreased the expression of fibrosis. In addition, RAN prevented cardiovascular death in rat model of PAH. These results support the notion that RAN can improve the functional properties of the RV, highlighting its potential benefits in the setting of heart impairment.

Involvement of veratridine-induced increase of reverse Na(+)/Ca(2+) exchange current in intracellular Ca(2+) overload and extension of action potential duration in rabbit ventricular myocytes / 生理学报

The objectives of this study were to investigate the effects of veratridine (VER) on persistent sodium current (I(Na.P)), Na(+)/Ca(2+) exchange current (I(NCX)), calcium transients and the action potential (AP) in rabbit ventricular myocytes, and to explore the mechanism in intracellular calcium overload and myocardial contraction enhancement by using whole-cell patch clamp recording technique, visual motion edge detection system, intracellular calcium measurement system and multi-channel physiological signal acquisition and processing system. The results showed that I(Na.P) and reverse I(NCX) in ventricular myocytes were obviously increased after giving 10, 20 μmol/L VER, with the current density of I(Na.P) increasing from (-0.22 ± 0.12) to (-0.61 ± 0.13) and (-2.15 ± 0.14) pA/pF (P < 0.01, n = 10) at -20 mV, and that of reverse I(NCX) increasing from (1.62 ± 0.12) to (2.19 ± 0.09) and (2.58 ± 0.11) pA/pF (P < 0.05, n = 10) at +50 mV. After adding 4 μmol/L tetrodotoxin (TTX), current density of I(Na.P) and reverse I(NCX) returned to (-0.07 ± 0.14) and (1.69 ± 0.15) pA/pF (P < 0.05, n = 10). Another specific blocker of I(Na.P), ranolazine (RAN), could obviously inhibit VER-increased I(Na.P) and reverse I(NCX). After giving 2.5 μmol/L VER, the maximal contraction rate of ventricular myocytes increased from (-0.91 ± 0.29) to (-1.53 ± 0.29) μm/s (P < 0.01, n = 7), the amplitude of contraction increased from (0.10 ± 0.04) to (0.16 ± 0.04) μm (P < 0.05, n = 7), and the baseline of calcium transients (diastolic calcium concentration) increased from (1.21 ± 0.08) to (1.37 ± 0.12) (P < 0.05, n = 7). After adding 2 μmol/L TTX, the maximal contraction rate and amplitude of ventricular myocytes decreased to (-0.86 ± 0.24) μm/s and (0.09 ± 0.03) μm (P < 0.01, n = 7) respectively. And the baseline of calcium transients reduced to (1.17 ± 0.09) (P < 0.05, n = 7). VER (20 μmol/L) could extend action potential duration at 50% repolarization (APD(50)) and at 90% repolarization (APD(90)) in ventricular myocytes from (123.18 ± 23.70) to (271.90 ± 32.81) and from (146.94 ± 24.15) to (429.79 ± 32.04) ms (P < 0.01, n = 6) respectively. Early afterdepolarizations (EADs) appeared in 3 out of the 6 cases. After adding 4 μmol/L TTX, APD(50) and APD(90) were reduced to (99.07 ± 22.81) and (163.84 ± 26.06) ms (P < 0.01, n = 6) respectively, and EADs disappeared accordingly in 3 cases. It could be suggested that: (1) As a specific agonist of the I(Na.P), VER could result in I(Na.P) increase and intracellular Na(+) overload, and subsequently intracellular Ca(2+) overload with the increase of reverse I(NCX). (2) The VER-increased I(Na.P) could further extend the action potential duration (APD) and induce EADs. (3) TTX could restrain the abnormal VER-induced changes of the above-mentioned indexes, indicating that these abnormal changes were caused by the increase of I(Na.P). Based on this study, it is concluded that as the I(Na.P) agonist, VER can enhance reverse I(NCX) by increasing I(Na.P), leading to intracellular Ca(2+) overload and APD abnormal extension.

Analysis of primary metabolites of ranolazine in dog urine by LC-MS(n) / 药学学报

Ranolazine and metabolites in dog urine were identified by LC-MS(n). Dog urine samples were collected after ig 30 mg x kg(-1) ranolazine, then the samples were enriched and purified through solid-phase extraction cartridge. The purified samples were analyzed by LC-MS(n). The possible metabolites were discovered by comparing the full scan and SIM chromatograms of the test samples with the corresponding blanks. Seventeen phase I metabolites and fourteen phase II metabolites were identified in dog urine. Three metabolites were identified by comparing with the control article. The metabolites were formed via the following metabolic pathways: O-demethylation, O-dearylation, hydroxylation, N-dealkylation, amide hydrolysis, glucuronidation and sulfation. The LC-MS(n) method is suitable for the rapid identification of drug and its metabolites in biologic samples.

Optimization of the formulation of ranolazine hydrochloride sustained-release tablet and its pharmacokinetics in dogs / 药学学报

Ranolazine hydrochloride sustained-release tablet (RH-ST) was prepared and its release behavior in vitro was studied. The pharmacokinetic characteristics and bioavailability in six Beagle dogs after oral administration of RH-ST and ranolazine hydrochloride common tablets (RH-CT) as reference were compared. Three kinds of matrix, hydroxypropylmethylcellulose (HPMC K4M), ethylcellulose (EC 100cp) and acrylic resins (Eudragit RL100) were selected as functional excipients to keep ranolazine hydrochloride (RH) release for 12 hours. Through orthogonal designs, the polymers were quantified and the optimized cumulative release profile was obtained. The single oral dose of RH-ST 500 mg and RH-CT 333.3 mg was given to six dogs using a two way crossover design. Plasma levels were determined by LC-MS and the absorption fractions were calculated according to Loo-Riegelman formula. The steady-state concentration of RH in plasma of six dogs and its pharmacokinetics behaviors after continuous oral administration of RH-ST and RH-CT at different time intervals were studied by LC-MS. The steady-state pharmacokinetic parameters were computed by software program BAPP2.0. With the increase of the amount of the matrix, the drug release was decreased. The most important factor influencing drug release is the quantity of HPMC K4M. Drug release within the period (from 0 h to 12 h) fitted well into Higuchi model. The correlation coefficient (r) between the dissolution in vitro in release media of the distilled water and the absorptin fraction in vivo was 0.9550. To compare with RH-CT, RH-ST in vivo has a steady and slow release behavior, Tmax was obviously delayed (3.00 +/- 0.50) h and the relative bioavailability was over 80 percentage. The combined use of multiple polymers can decrease the tablet weight effectively, and the drug release rate can be decreased both in vitro and in vivo.

Determination of residual solvents in ranolazine by headspace gas chromatography / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine the contents of the residual solvents, methanol, ethanol, toluene, dichloromethane and dioxane in ranolazine raw material.</p><p><b>METHODS</b>Headspace gas chromatography was used to analyze the residual solvents quantitatively. Samples were analyzed on an HP-INNOWAX column with column temperature at 45 degrees Celsius; using water as solvent.</p><p><b>RESULTS</b>Five residual solvents were completely separated. The liner range and recoveries were satisfied. RSD of precision and accuracy was less than 8% with average recoveries between 87.1% and 105.6%.</p><p><b>CONCLUSION</b>The method could be used for the quality control of ranolazine raw material.</p>

Mecanismos celulares y moleculares subyacentes de las arritmias cardíacas inducidas por drogas y asociadas con la prolongación del intervalo QT / Cellular and molecular mechanisms underlying drug-induced cardiac arrhythmias associated with prolongation of the QT interval

Drug-induced QT prolongation is sometimes associated with life-threatening torsade de pointes (TdP) arrhythmias that develop as a consequence of the amplification of electrical heterogeneities intrinsic to the ventricular myocardium. These heterogeneities exist because of differences in the time course of repolarization of the three predominant cell types that comprise the ventricular myocardium, giving rise to transmural voltage gradients and a dispersion of repolarization responsible for the inscription of the T wave in the electrocardiogram (ECG). Drugs and conditions that reduce net repolarizing current produce a preferential prolongation of the M cell action potential and thus amplify the intrinsic spatial dispersion of repolarization, creating the substrate for the development of reentry. The result is a prolongation of the QT interval, abnormal T waves and the development of polymorphic reentrant ventricular tachycardia displaying characteristics of TdP. These conditions also predispose M cells and Purkinje fibers to develop early afterdepolarization (EAD)-induced extrasystoles, which are thought to trigger the episodes of TdP. A reduction of net repolarizing current thus provides both the substrate and trigger for the initiation of the reentrant arrhythmia believed to underlie TdP. Agents that prolong the QT interval but do not increase transmural dispersion of repolarization, including sodium pentobarbital, amiodarone and ranolazine, generally do not induce TdP. The available data suggest that that the principal problem with both acquired and congenital long QT syndromes is not long QT intervals, but rather the dispersion of repolarization that often accompanies prolongation of the QT interval.

La prolongación del intervalo QT en ocasiones se asocia con torsade de pointes (TdP), arritmias que ponen en riesgo la vida, que se desarrollan como consecuencia de la amplificación de heterogeneidades eléctricas propias del miocardio ventricular. Estas existen debido a las diferencias en el tiempo de repolarización de los tres tipos celulares predominantes que conforman el miocardio ventricular, los que dan origen a gradientes de voltaje transmural y a una dispersión de la repolarización responsable del registro de la onda T en el electrocardiograma (ECG). Las drogas y los trastornos que reducen la corriente de repolarización neta producen una prolongación preferencial del potencial de acción de la célula M y de esta forma amplifican la dispersión espacial intrínseca de la repolarización, lo que crea el sustrato para la reentrada. El resultado es la prolongación del intervalo QT, ondas T anormales y la aparición de taquicardia ventricular polimórfica por reentrada que muestra características de TdP. Estos trastornos también predisponen a extrasístoles inducidas por posdespolarizaciones tempranas de las células M y las fibras de Purkinje, las cuales se cree desencadenan los episodios de TdP. Una reducción de la corriente de repolarización neta, de esta manera, aporta el sustrato y el mecanismo desencadenante para el inicio de la arritmia por reentrada que se cree yace en la TdP. Los agentes que prolongan el intervalo QT pero que no incrementan la dispersión transmural de la repolarización, como pentobarbital sódico, amiodarona y ranolazina, por lo general no inducen TdP. Los datos disponibles sugieren que el problema principal tanto en los síndromes congénitos y adquiridos de QT prolongado no es el alargamiento del intervalo QT, sino la dispersión de la repolarización que habitualmente acompaña su prolongación.