Intracellular uptake of agents that block the hERG channel can confound the assessment of QT interval prolongation and arrhythmic risk.

BACKGROUND: Oliceridine is a biased ligand at the µ-opioid receptor recently approved for the treatment of acute pain. In a thorough QT study, corrected QT (QTc) prolongation displayed peaks at 2.5 and 60 minutes after a supratherapeutic dose. The mean plasma concentration peaked at 5 minutes, declining rapidly thereafter. OBJECTIVE: The purpose of this study was to examine the basis for the delayed effect of oliceridine to prolong the QTc interval. METHODS: Repolarization parameters and tissue accumulation of oliceridine were evaluated in rabbit left ventricular wedge preparations over a period of 5 hours. The effects of oliceridine on ion channel currents were evaluated in human embryonic kidney and Chinese hamster ovary cells. Quinidine was used as a control. RESULTS: Oliceridine and quinidine produced a progressive prolongation of the QTc interval and action potential duration over a period of 5 hours, paralleling slow progressive tissue uptake of the drugs. Oliceridine caused modest prolongation of these parameters, whereas quinidine produced a prominent prolongation of action potential duration and QTc interval as well as development of early afterdepolarization (after 2 hours), resulting in a high torsades de pointes score. The 50% inhibitory concentration values for the oliceridine inhibition of the rapidly activating delayed rectifier current (human ether a-go-go current) and late sodium channel current were 2.2 and 3.45 µM when assessed after traditional acute exposure but much lower after 3 hours of drug exposure. CONCLUSION: Our findings suggest that a gradual increase of intracellular access of drugs to the hERG channels as a result of their intracellular uptake and accumulation can significantly delay effects on repolarization, thus confounding the assessment of QT interval prolongation and arrhythmic risk when studied acutely. The multi-ion channel effects of oliceridine, late sodium channel current inhibition in particular, point to a low risk of devloping torsades de pointes.

Rate-dependent effects of lidocaine on cardiac dynamics: Development and analysis of a low-dimensional drug-channel interaction model.

State-dependent sodium channel blockers are often prescribed to treat cardiac arrhythmias, but many sodium channel blockers are known to have pro-arrhythmic side effects. While the anti and proarrhythmic potential of a sodium channel blocker is thought to depend on the characteristics of its rate-dependent block, the mechanisms linking these two attributes are unclear. Furthermore, how specific properties of rate-dependent block arise from the binding kinetics of a particular drug is poorly understood. Here, we examine the rate-dependent effects of the sodium channel blocker lidocaine by constructing and analyzing a novel drug-channel interaction model. First, we identify the predominant mode of lidocaine binding in a 24 variable Markov model for lidocaine-sodium channel interaction by Moreno et al. Specifically, we find that (1) the vast majority of lidocaine bound to sodium channels is in the neutral form, i.e., the binding of charged lidocaine to sodium channels is negligible, and (2) neutral lidocaine binds almost exclusively to inactivated channels and, upon binding, immobilizes channels in the inactivated state. We then develop a novel 3-variable lidocaine-sodium channel interaction model that incorporates only the predominant mode of drug binding. Our low-dimensional model replicates an extensive amount of the voltage-clamp data used to parameterize the Moreno et al. model. Furthermore, the effects of lidocaine on action potential upstroke velocity and conduction velocity in our model are similar to those predicted by the Moreno et al. model. By exploiting the low-dimensionality of our model, we derive an algebraic expression for level of rate-dependent block as a function of pacing frequency, restitution properties, diastolic and plateau potentials, and drug binding rate constants. Our model predicts that the level of rate-dependent block is sensitive to alterations in restitution properties and increases in diastolic potential, but it is insensitive to variations in the shape of the action potential waveform and lidocaine binding rates.

Lacosamide induced Brugada I morphology in the setting of septicemia: A case report.

INTRODUCTION: Brugada syndrome may be unmasked by non-antiarrhythmic pharmaceuticals or drugs. Lacosamide is an antiepileptic agent with a novel mechanism of sodium channel inhibition and has the potential to cause cardiac sodium channel blockade. PATIENT CONCERNS: In this report, we describe the case of patient with a history of a seizure disorder who presented with Brugada I electrocardiogram morphology in the setting of septicemia. DIAGNOSIS: Brugada I electrocardiogram morphology was unmasked by lacosamide antiepileptic monotherapy. INTERVENTIONS: Lacosamide therapy was discontinued. OUTCOMES: Normalization of the electrocardiogram and resolution of Brugada morphology occurred on hospital day 1. CONCLUSION: Caution should be exercised in the use of lacosamide in those at risk for conduction delay, or in combination therapy with medications that impair renal clearance, metabolism of lacosamide, or that display inherent sodium channel blocking properties.

Population Pharmacokinetics of Vixotrigine in Healthy Volunteers and Subjects with Trigeminal Neuralgia, Painful Lumbosacral Radiculopathy and Erythromelalgia.

BACKGROUND: Vixotrigine is a voltage and use dependent sodium channel blocker currently under development for treatment of various neuropathic pain indications. OBJECTIVE: The objective of this work was to develop a population pharmacokinetic model and assess effects of various covariates on pharmacokinetic parameters of vixotrigine. METHOD: Plasma concentration-time data from 12 Phase 1 or 2 studies were included in the analyses. The data were obtained following administration of single or multiple doses of vixotrigine in healthy volunteers and patients. One- and two-compartment pharmacokinetic models were evaluated as base structural pharmacokinetic models. The inclusion of selected covariates was assessed using a stepwise backward elimination approach (α = 0.001) once the base/full model was developed. The predictive ability of the model was evaluated using a visual predictive check (VPC). The final model was used to evaluate effect of covariates on exposure of vixotrigine. RESULTS: A total of 10,263 pharmacokinetic samples collected from 465 subjects were included in the analyses. The pharmacokinetics of vixotrigine was adequately described by a two-compartment model with two transit absorption compartments and first-order elimination. Predictability of the model was also established by VPC. The final model included covariates of age, weight and carbamazepine co-administration on clearance, weight on central volume of distribution, food on absorption rate constant and formulation and Japanese race on bioavailability. None of the covariates identified had a clinically relevant effect, as impact on area under the plasma concentration-time curve (AUC) and maximum plasma concentration (Cmax) was within ± 25%. CONCLUSION: The model characterizes the pharmacokinetics of vixotrigine well, and the exposure of vixotrigine was comparable between healthy subjects and patients. None of the covariates evaluated have a clinically relevant impact on the pharmacokinetics of vixotrigine.

Discovery of Acyl-sulfonamide Nav1.7 Inhibitors GDC-0276 and GDC-0310.

Nav1.7 is an extensively investigated target for pain with a strong genetic link in humans, yet in spite of this effort, it remains challenging to identify efficacious, selective, and safe inhibitors. Here, we disclose the discovery and preclinical profile of GDC-0276 (1) and GDC-0310 (2), selective Nav1.7 inhibitors that have completed Phase 1 trials. Our initial search focused on close-in analogues to early compound 3. This resulted in the discovery of GDC-0276 (1), which possessed improved metabolic stability and an acceptable overall pharmacokinetics profile. To further derisk the predicted human pharmacokinetics and enable QD dosing, additional optimization of the scaffold was conducted, resulting in the discovery of a novel series of N-benzyl piperidine Nav1.7 inhibitors. Improvement of the metabolic stability by blocking the labile benzylic position led to the discovery of GDC-0310 (2), which possesses improved Nav selectivity and pharmacokinetic profile over 1.

Aspectos farmacológicos diferenciales entre los bloqueadores de los canales de sodio dependientes de voltaje: implicaciones en la práctica clínica / Differential pharmacological aspects between voltage-gated sodium channel blockers: implications in clinical practice

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Inhibition of neuronal Na+ currents by lacosamide: Differential binding affinity and kinetics to different inactivated states.

Lacosamide is a new-generation anticonvulsant acting on Na+ channels. Compared to the classic anticonvulsants targeting Na+ channels, lacosamide is unique in structure and in its molecular action requiring longer membrane depolarization. Selective binding to the slow inactivated state of Na+ channels was then advocated for lacosamide, although slow binding to the fast inactivated state was alternatively proposed recently. In addition, quantitative characterization of lacosamide action has been deficient. We investigated the interactions between lacosamide and Na+ channels in native mammalian neurons, and found that the apparent dissociation constant (~13.7 µM) of lacosamide to the slow inactivated state is well within the therapeutic concentration range and is much (>15-fold) lower than the dissociation constant of lacosamide to the fast inactivated state. Besides, lacosamide has extremely slow binding rates (<400 M-1sec-1) to the fast but much faster binding rates (>3000 M-1sec-1) to the slow inactivated Na+ channels. Consistent with these biophysical characters, we further demonstrated that lacosamide is much more effective against the repetitive burst discharges with interburst intervals at -60 mV than -80 mV. With preponderant binding to the slow inactivation state in therapeutic concentrations and thus less propensity to affect normal discharges, lacosamide could be a drug of choice for seizure discharges characterized by relatively depolarized interburst intervals, during which more slow inactivated states could be generated and more binding of lacosamide would ensue.

Discovery of Potent, Selective, and State-Dependent NaV1.7 Inhibitors with Robust Oral Efficacy in Pain Models: Structure-Activity Relationship and Optimization of Chroman and Indane Aryl Sulfonamides.

Voltage-gated sodium channel NaV1.7 is a genetically validated target for pain. Identification of NaV1.7 inhibitors with all of the desired properties to develop as an oral therapeutic for pain has been a major challenge. Herein, we report systematic structure-activity relationship (SAR) studies carried out to identify novel sulfonamide derivatives as potent, selective, and state-dependent NaV1.7 inhibitors for pain. Scaffold hopping from benzoxazine to chroman and indane bicyclic system followed by thiazole replacement on sulfonamide led to identification of lead molecules with significant improvement in solubility, selectivity over NaV1.5, and CYP2C9 inhibition. The lead molecules 13, 29, 32, 43, and 51 showed a favorable pharmacokinetics (PK) profile across different species and robust efficacy in veratridine and formalin-induced inflammatory pain models in mice. Compound 51 also showed significant effects on the CCI-induced neuropathic pain model. The profile of 51 indicated that it has the potential for further evaluation as a therapeutic for pain.

Evaluation of the Pharmacokinetic Interaction Between the Voltage- and Use-Dependent Nav1.7 Channel Blocker Vixotrigine and Carbamazepine in Healthy Volunteers.

Vixotrigine is a voltage- and use-dependent Nav1.7 channel blocker under investigation for the treatment of peripheral neuropathic pain conditions, including trigeminal neuralgia. Vixotrigine is metabolized primarily via uridine diphosphate-glucuronosyltransferases (UGTs). Carbamazepine, a UGT and cytochrome P450 3A4 inducer, is a first-line treatment for trigeminal neuralgia. We conducted a double-blind, randomized, placebo-controlled, parallel-group, single-center phase 1 study to investigate the impact of coadministering vixotrigine and carbamazepine on their respective pharmacokinetics (PK) in healthy volunteers, the safety and tolerability of combined treatment, and PK recovery of vixotrigine following carbamazepine discontinuation. Randomly assigned treatments were carbamazepine (100 mg twice a day, days 1-3 and 200 mg twice a day, days 4-21) or placebo on days 1 to 21. All volunteers received vixotrigine 150 mg 3 times a day on days 16 to 28. At prespecified times, whole-blood samples were collected for PK assessment. Statistical analyses were performed on the log-transformed PK parameters area under the concentration-time curve within a dosing interval (AUC0-tau ) and maximum observed concentration (Cmax ) for vixotrigine, carbamazepine, and metabolites. Vixotrigine AUC0-tau and Cmax were reduced by 31.6% and 26.3%, respectively, when coadministered with carbamazepine compared with placebo. Seven days after carbamazepine discontinuation, vixotrigine AUC0-tau and Cmax remained 24.5% and 21.4% lower compared with placebo. Carbamazepine AUC0-tau and Cmax were <10% lower when coadministered with vixotrigine compared on days 15 and 21. Vixotrigine/carbamazepine coadministration was well tolerated. These results suggest that vixotrigine does not have an effect on carbamazepine PK, and although carbamazepine has an effect on the exposure of vixotrigine, the effect is not considered clinically relevant.

Use of Cryopreserved Hepatocytes as Part of an Integrated Strategy to Characterize In Vivo Clearance for Peptide-Antibody Conjugate Inhibitors of Nav1.7 in Preclinical Species.

The identification of nonopioid alternatives to treat chronic pain has received a great deal of interest in recent years. Recently, the engineering of a series of Nav1.7 inhibitory peptide-antibody conjugates has been reported, and herein, the preclinical efforts to identify novel approaches to characterize the pharmacokinetic properties of the peptide conjugates are described. A cryopreserved plated mouse hepatocyte assay was designed to measure the depletion of the peptide-antibody conjugates from the media, with a correlation being observed between percentage remaining in the media and in vivo clearance (Pearson r = -0.5525). Physicochemical (charge and hydrophobicity), receptor-binding [neonatal Fc receptor (FcRn)], and in vivo pharmacokinetic data were generated and compared with the results from our in vitro hepatocyte assay, which was hypothesized to encompass all of the aforementioned properties. Correlations were observed among hydrophobicity; FcRn binding; depletion rates from the hepatocyte assay; and ultimately, in vivo clearance. Subsequent studies identified potential roles for the low-density lipoprotein and mannose/galactose receptors in the association of the Nav1.7 peptide conjugates with mouse hepatocytes, although in vivo studies suggested that FcRn was still the primary receptor involved in determining the pharmacokinetics of the peptide conjugates. Ultimately, the use of the cryopreserved hepatocyte assay along with FcRn binding and hydrophobic interaction chromatography provided an efficient and integrated approach to rapidly triage molecules for advancement while reducing the number of in vivo pharmacokinetic studies. SIGNIFICANCE STATEMENT: Although multiple in vitro and in silico tools are available in small-molecule drug discovery, pharmacokinetic characterization of protein therapeutics is still highly dependent upon the use of in vivo studies in preclinical species. The current work demonstrates the combined use of cryopreserved hepatocytes, hydrophobic interaction chromatography, and neonatal Fc receptor binding to characterize a series of Nav1.7 peptide-antibody conjugates prior to conducting in vivo studies, thus providing a means to rapidly evaluate novel protein therapeutic platforms while concomitantly reducing the number of in vivo studies conducted in preclinical species.

Mucoadhesive Electrospun Patch Delivery of Lidocaine to the Oral Mucosa and Investigation of Spatial Distribution in a Tissue Using MALDI-Mass Spectrometry Imaging.

Many oral mucosal conditions cause considerable and prolonged pain that to date has been difficult to alleviate via topical delivery, and the use of injection causes many patients dental anxiety and needle-prick pain. Therefore, developing a noninjectable drug delivery system as an alternative administration procedure may vastly improve the health and wellbeing of these patients. Recent advances in the development of mucoadhesive electrospun patches for the direct delivery of therapeutics to the oral mucosa offer a potential solution, but as yet, the release of local anesthetics from this system and their uptake by oral tissue have not been demonstrated. Here, we demonstrate the fabrication of lidocaine-loaded electrospun fiber patches, drug release, and subsequent uptake and permeation through the porcine buccal mucosa. Lidocaine HCl and lidocaine base were incorporated into the electrospun patches to evaluate the difference in drug permeation for the two drug compositions. Lidocaine released from the lidocaine HCl-containing electrospun patches was significantly quicker than from the lidocaine base patches, with double the amount of drug released from the lidocaine HCl patches in the first 15 min (0.16 ± 0.04 mg) compared to that from the lidocaine base patches (0.07 ± 0.01 mg). The permeation of lidocaine from the lidocaine HCl electrospun patches through ex vivo porcine buccal mucosa was also detected in 15 min, whereas permeation of lidocaine from the lidocaine base patch was not detected. Matrix-assisted laser desorption ionization-mass spectrometry imaging was used to investigate localization of lidocaine within the oral tissue. Lidocaine in the solution as well as from the mucoadhesive patch penetrated into the buccal mucosal tissue in a time-dependent manner and was detectable in the lamina propria after only 15 min. Moreover, the lidocaine released from lidocaine HCl electrospun patches retained biological activity, inhibiting veratridine-mediated opening of voltage-gated sodium channels in SH-SY5Y neuroblastoma cells. These data suggest that a mucoadhesive electrospun patch may be used as a vehicle for rapid uptake and sustained anesthetic drug delivery to treat or prevent oral pain.

Engineering NaV1.7 Inhibitory JzTx-V Peptides with a Potency and Basicity Profile Suitable for Antibody Conjugation To Enhance Pharmacokinetics.

Drug discovery research on new pain targets with human genetic validation, including the voltage-gated sodium channel NaV1.7, is being pursued to address the unmet medical need with respect to chronic pain and the rising opioid epidemic. As part of early research efforts on this front, we have previously developed NaV1.7 inhibitory peptide-antibody conjugates with tarantula venom-derived GpTx-1 toxin peptides with an extended half-life (80 h) in rodents but only moderate in vitro activity (hNaV1.7 IC50 = 250 nM) and without in vivo activity. We identified the more potent peptide JzTx-V from our natural peptide collection and improved its selectivity against other sodium channel isoforms through positional analogueing. Here we report utilization of the JzTx-V scaffold in a peptide-antibody conjugate and architectural variations in the linker, peptide loading, and antibody attachment site. We found conjugates with 100-fold improved in vitro potency relative to those of complementary GpTx-1 analogues, but pharmacokinetic and bioimaging analyses of these JzTx-V conjugates revealed a shorter than expected plasma half-life in vivo with accumulation in the liver. In an attempt to increase circulatory serum levels, we sought the reduction of the net +6 charge of the JzTx-V scaffold while retaining a desirable NaV in vitro activity profile. The conjugate of a JzTx-V peptide analogue with a +2 formal charge maintained NaV1.7 potency with 18-fold improved plasma exposure in rodents. Balancing the loss of peptide and conjugate potency associated with the reduction of net charge necessary for improved target exposure resulted in a compound with moderate activity in a NaV1.7-dependent pharmacodynamic model but requires further optimization to identify a conjugate that can fully engage NaV1.7 in vivo.

The discovery and optimization of benzimidazoles as selective NaV1.8 blockers for the treatment of pain.

The voltage gated sodium channel NaV1.8 has been postulated to play a key role in the transmission of pain signals. Core hopping from our previously reported phenylimidazole leads has allowed the identification of a novel series of benzimidazole NaV1.8 blockers. Subsequent optimization allowed the identification of compound 9, PF-06305591, as a potent, highly selective blocker with an excellent preclinical in vitro ADME and safety profile.

Discovery of Tarantula Venom-Derived NaV1.7-Inhibitory JzTx-V Peptide 5-Br-Trp24 Analogue AM-6120 with Systemic Block of Histamine-Induced Pruritis.

Inhibitors of the voltage-gated sodium channel NaV1.7 are being investigated as pain therapeutics due to compelling human genetics. We previously identified NaV1.7-inhibitory peptides GpTx-1 and JzTx-V from tarantula venom screens. Potency and selectivity were modulated through attribute-based positional scans of native residues via chemical synthesis. Herein, we report JzTx-V lead optimization to identify a pharmacodynamically active peptide variant. Molecular docking of peptide ensembles from NMR into a homology model-derived NaV1.7 structure supported prioritization of key residues clustered on a hydrophobic face of the disulfide-rich folded peptide for derivatization. Replacing Trp24 with 5-Br-Trp24 identified lead peptides with activity in electrophysiology assays in engineered and neuronal cells. 5-Br-Trp24 containing peptide AM-6120 was characterized in X-ray crystallography and pharmacokinetic studies and blocked histamine-induced pruritis in mice after subcutaneous administration, demonstrating systemic NaV1.7-dependent pharmacodynamics. Our data suggests a need for high target coverage based on plasma exposure for impacting in vivo end points with selectivity-optimized peptidic NaV1.7 inhibitors.

The role of organic anion-transporting polypeptides and formulation in the clearance and distribution of a novel Nav 1.7 channel blocker.

PF-06456384 is an extremely potent and selective blocker of the Nav 1.7 sodium channel designed as a potential intravenous (i.v.) analgesic targeting high potency and rapid clearance to minimize the potential for residual effects following the end of infusion. In our previous experience targeting oral molecules, the requirement to obtain potent, Nav 1.7 selective molecules led to a focus on acidic, amphipilic compounds cleared primarily by organic anion-transporting polypeptide mediated hepatic uptake and subsequent biliary excretion. However, the physicochemical properties of the i.v. lead matter were substantially different, moving from acidic, amphiphilic chemical space to zwitterions as well as substantially increasing molecular weight. This report describes the continued relevance of organic anion-transporting polypeptide driven hepatic uptake in this physicochemical space and highlights an apparent impact of the formulation excipient Solutol on the clearance and distribution of PF-06456384.

Nav1.7 inhibitors for the treatment of chronic pain.

The voltage gated sodium channel Nav1.7 plays an essential role in the transmission of pain signals. Strong human genetic validation has motivated extensive efforts to discover potent, selective, and efficacious Nav1.7 inhibitors for the treatment of chronic pain. This digest will introduce the structure and function of Nav1.7 and highlight the wealth of recent developments on a diverse array of Nav1.7 inhibitors, including optimization of their potency, selectivity, and PK/PD relationships.

Design of Conformationally Constrained Acyl Sulfonamide Isosteres: Identification of N-([1,2,4]Triazolo[4,3- a]pyridin-3-yl)methane-sulfonamides as Potent and Selective hNaV1.7 Inhibitors for the Treatment of Pain.

The sodium channel NaV1.7 has emerged as a promising target for the treatment of pain based on strong genetic validation of its role in nociception. In recent years, a number of aryl and acyl sulfonamides have been reported as potent inhibitors of NaV1.7, with high selectivity over the cardiac isoform NaV1.5. Herein, we report on the discovery of a novel series of N-([1,2,4]triazolo[4,3- a]pyridin-3-yl)methanesulfonamides as selective NaV1.7 inhibitors. Starting with the crystal structure of an acyl sulfonamide, we rationalized that cyclization to form a fused heterocycle would improve physicochemical properties, in particular lipophilicity. Our design strategy focused on optimization of potency for block of NaV1.7 and human metabolic stability. Lead compounds 10, 13 (GNE-131), and 25 showed excellent potency, good in vitro metabolic stability, and low in vivo clearance in mouse, rat, and dog. Compound 13 also displayed excellent efficacy in a transgenic mouse model of induced pain.

Papel de los bloqueadores de los canales de sodio dependientes de voltaje en el tratamiento del dolor crónico: usos potenciales en la práctica clínica según la evidencia disponible / Role of voltage-gated sodium channel blockers in the treatment of chronic pain: Potential uses in clinical practice based on available evidence

Una vez que ha fracasado el tratamiento de primera línea en los pacientes con dolor crónico, parece haber una laguna de conocimiento sobre cómo proceder en la elección de un tratamiento posterior. Este artículo se centra en el uso de los bloqueadores de los canales de sodio dependientes de voltaje que pertenecen a la clase de las carboxamidas (carbamazepina, oxcarbazepina, acetato de eslicarbazepina) como tratamiento analgésico adyuvante; e incluye actualizaciones sobre farmacología, farmacocinética y evidencias en dolor de este grupo terapéutico, así como prometedoras futuras líneas de investigación. Aunque la evidencia de los bloqueadores de los canales de sodio dependientes de voltaje en el manejo del dolor crónico es limitada, la investigación emergente ha identificado esta área como esperanzadora para que ensayos clínicos adicionales guíen mejor nuestra práctica clínica

Once patients have failed first line therapy, there is an apparent lack of knowledge on how to proceed with choosing subsequent therapy. To choose amongst alternative agents, an understanding of pharmacology, pharmacokinetics, and available evidence in targeting various pain conditions is necessary. This article focuses on the use of the carboxamide class of voltage-gated sodium channel blockers (carbamazepine, oxcarbazepine, eslicarbazepine acetate) for adjunct pain medication management; including research updates in pharmacology, pharmacokinetics, and evidence for pain along on this therapeutic group with promising future areas of research. Although evidence for voltage-gated sodium channel blockers in chronic pain management is limited, emerging research has identified this area as promising for additional clinical trials to better guide clinical practice

A Focus on the Synthesis and Pharmacokinetics of Tocainide and its Analogues.

Tocainide is an antiarrhythmic agent belonging to class IB that was primarily used for suppression of symptomatic ventricular arrhythmias. Tocainide was also reported to relieve pain such as tic douloureux, trigemina neuralgia in humans and tinnitus. Significant antinociception, as assayed on the hot-plate test, was observed after intraperitoneal injection of tocainide, too. By the mid-1980s tocainide was emerging as a more consistently effective treatment for myotonic disorders. Numerous reports of serious adverse reactions led to the use of tocainide being discontinued, even though research on tocainide and its analogues, endowed with a better pharmacological profile, is still in progress for their potential usefulness in the treatment of myotonias. This review is focused on the description of the different synthetic routes to racemic and optically active tocainide developed in the last decades, as well as analytical studies regarding enantioseparation methods. Finally, some analogues of tocainide reported in the literature, most of which with pharmacological studies, have been mentioned.