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The immortalized mouse liver cell line TAMH has been described as a valuable tool for studying hepatotoxic mechanisms, but until now, it has only been reported to grow as a monolayer in culture. However, culturing hepatocytes as three‐dimensional (3D) spheroids has been shown to result in improved liver‐specific functions (e.g., metabolic capacity) by better mimicking the in vivo environment. This approach may lead to more reliable detection of drug‐induced liver injury (DILI) in the early phase of drug discovery, preventing post‐marketing drug withdrawals. Here, we investigated the cultivation of TAMH as 3D spheroids, characterizing them with optical and transmission electron microscopy as well as analyzing their gene expression at mRNA level (especially drug‐metabolizing enzymes) compared to TAMH monolayer. In addition, comparisons were made with spheroids grown from the human hepatoblastoma cell line HepG2, another current spheroid model. The results indicate that TAMH spheroids express hepatic structures and show elevated levels of some of the key phase I and II drug‐metabolizing enzymes, in contrast to TAMH monolayer. The in vitro hepatotoxic potencies of the drugs acetaminophen and flupirtine maleate were found to be very similar between TAMH spheroidal and the monolayer cultures. Both the advantages and disadvantages of TAMH spheroids as an in vitro hepatotoxicity model compared to monolayer model are discussed. 3D, or not 3D, that is the question! The TGF‐α‐overexpressing mouse hepatocyte cell line TAMH had been used as a monolayer (2D) in several studies to evaluate the hepatotoxicity of drugs in vitro. Here, we investigated whether TAMH cultured as three‐dimensional (3D) spheroids showed improved liver‐specific properties and could function as an in vitro model to study drug‐induced liver injury with comparison to other current spheroid models. [ABSTRACT FROM AUTHOR]

Background: Third molar surgery is a common dental procedure often associated with significant postoperative pain. This study aimed to compare the efficacy of three commonly used analgesic agents, ketorolac, tramadol, and flupirtine, in managing postoperative pain following third molar surgery. Materials and Methods: A randomized controlled trial was conducted with 150 patients who underwent third molar extraction. The patients were divided into three groups, with 50 patients in each group. Group A received ketorolac 10 mg orally every 6 hours, Group B received tramadol 50 mg orally every 6 hours, and Group C received flupirtine 100 mg orally every 8 hours for 72 hours post-surgery. Pain intensity was assessed using a visual analog scale (VAS), and the total analgesic consumption was recorded. Adverse effects were monitored throughout the study period. Results: The mean pain scores at different time intervals (0-24 hours, 24-48 hours, and 48-72 hours) were significantly lower in the ketorolac group compared to the tramadol and flupirtine groups (p < 0.05). The total analgesic consumption in the ketorolac group was significantly lower (p < 0.05) than in the tramadol and flupirtine groups. Adverse effects were mild and comparable among the three groups. Conclusion: Ketorolac demonstrated superior analgesic efficacy in the management of postoperative pain following third molar surgery when compared to tramadol and flupirtine. It also resulted in reduced analgesic consumption and had a similar safety profile. Therefore, ketorolac may be considered the preferred analgesic agent for patients undergoing third molar surgery. [ABSTRACT FROM AUTHOR]

Background and Aims: Flupirtine has been used for various chronic pain conditions, but its utility in the perioperative period as an analgesic is still inconclusive. This systematic review and meta-analysis aimed to assess the efficacy of flupirtine for postoperative pain. Methods: PubMed, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) were explored for the randomised controlled trials (RCTs) which compared flupirtine with other analgesic/placebo for perioperative pain in adult patients undergoing surgery. The standardised mean difference (SMD) of pain scores, the need for rescue analgesia and all adverse effects were assessed. Heterogeneity was assessed using Cochrane's Q statistic test and I2 statistic. Cochrane Collaboration's tool was used to evaluate the risk of bias and the quality of the RCTs. Results: A total of 13 RCTs (including 1,014 patients) that evaluated the use of flupirtine for postoperative pain were included in the study. The pooled SMD of postoperative pain scores revealed that flupirtine and other analgesics were comparable at 0, 6, 12 and 24 hours (P > 0.05), while at 48 hours, flupirtine showed poor pain control (P = 0.04) as compared to other analgesics. There were no significant differences at other time points and on comparison of flupirtine with placebo. The side effect profile was comparable between flupirtine and other analgesics. Conclusion: The current evidence suggests that perioperative flupirtine was not superior to other most commonly used analgesics and placebo for the treatment of postoperative pain.

Rationale: Drug combinations are commonly used in pain management, which can produce potent analgesic effects with reduced dosage and adverse effects. Objective: This study was designed to evaluate the anti-nociceptive effects and adverse effects of new combinations of flupirtine (a Kv7 potassium channel opener) and antihistamines (promethazine, fexofenadine) on acute and chronic pain in mice, and the possible mechanisms behind the synergistic analgesic effects were preliminarily investigated. Methods: In acetic acid writhing test, carrageenan-induced inflammatory pain model, and paclitaxel-induced neuropathic pain model, the interaction indexes (γ) between flupirtine and antihistamines were determined by isobolographic analysis. Furthermore, the Kv7 channel blocker XE991 was used to determine whether the effects of single agents and drug combinations on paclitaxel- and carrageenan-induced mechanical allodynia were mediated by Kv7 channels. Finally, hepatotoxicity markers, liver histopathology, and the rotarod test were used to investigate the adverse effects of drugs in combination doses. Results: The interaction indexes of flupirtine-promethazine and flupirtine-fexofenadine in all the above three pain models were lower than 1. The analgesic effects of flupirtine (13 mg/kg), promethazine (5 mg/kg), fexofenadine (20 mg/kg), and their combinations were antagonized significantly by XE991 (3 mg/kg). And the adverse effects of flupirtine and antihistamines in combination doses were not significantly different from the vehicle group. Conclusions: Flupirtine and antihistamines produced synergistic analgesic effects in all the above pain models. The analgesic effects of antihistamines were partially mediated by Kv7/M channels, and the activation of Kv7/M channels may be partly responsible for the synergistic analgesic effects between flupirtine and antihistamines. [ABSTRACT FROM AUTHOR]

Background and Aims: Flupirtine has been used for various chronic pain conditions, but its utility in the perioperative period as an analgesic is still inconclusive. This systematic review and meta-analysis aimed to assess the efficacy of flupirtine for postoperative pain. Methods: PubMed, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) were explored for the randomised controlled trials (RCTs) which compared flupirtine with other analgesic/placebo for perioperative pain in adult patients undergoing surgery. The standardised mean difference (SMD) of pain scores, the need for rescue analgesia and all adverse effects were assessed. Heterogeneity was assessed using Cochrane's Q statistic test and I2 statistic. Cochrane Collaboration's tool was used to evaluate the risk of bias and the quality of the RCTs. Results: A total of 13 RCTs (including 1,014 patients) that evaluated the use of flupirtine for postoperative pain were included in the study. The pooled SMD of postoperative pain scores revealed that flupirtine and other analgesics were comparable at 0, 6, 12 and 24 hours (P > 0.05), while at 48 hours, flupirtine showed poor pain control (P = 0.04) as compared to other analgesics. There were no significant differences at other time points and on comparison of flupirtine with placebo. The side effect profile was comparable between flupirtine and other analgesics. Conclusion: The current evidence suggests that perioperative flupirtine was not superior to other most commonly used analgesics and placebo for the treatment of postoperative pain. [ABSTRACT FROM AUTHOR]

Objectives: Paclitaxel and docetaxel are two commonly used chemotherapeutic agents in the treatment of various types of cancers. However, debilitating taxane-induced arthralgia and myalgia are among the most common adverse reactions associated with taxanes, which has greatly influenced medical practitioners. Most of the mild and moderate analgesics were found to be less effective in the management of taxane induced pain. So we used flupirtine, a non-opioid analgesic, in the treatment of taxane-induced pain. Materials and Methods: In this study, we analysed the baseline pain score and follow-up data of 60 patients receiving a taxane-based chemotherapy regimen. Baseline data of these study populations experiencing significant taxane-induced pain were compared with follow-up data after treating them with analgesic flupirtine (200 mg/day). The baseline and follow-up data representing pain were assessed with the help of the Visual Analogue Scale (VAS), and the quality of life was determined using the Brief Pain Inventory (BPI) scale questionnaire. Results: The mean baseline and follow-up VAS score was compared using paired sample t-test, which showed a significant reduction in taxane-induced pain after treatment with flupirtine (P < 0.001). Similarly, the mean BPI score representing the quality of life before and after treatment with flupirtine was compared, and a notable improvement in quality of life was seen after treatment with flupirtine. The mean and follow-up data of aspartate aminotransferase and alanine aminotransferase levels of patients were also compared to assess the adverse drug reaction profile of the drug, and the analyzed data was found to be statistically insignificant (no significant liver toxicity) which indicates that drug can be used effectively for a period of <2 weeks. Conclusion: We believe that flupirtine can be used as an effective analgesic in dire situations where patients require opioid analgesics for the management of taxane-induced pain, provided that the drug is given for <2 weeks to avoid drug-related hepatotoxicity. [ABSTRACT FROM AUTHOR]

Introduction: The most commonly performed surgical procedure in most oral and maxillofacial surgery practices is the removal of third molars. Postoperative pain is considered a form of acute pain due to surgical trauma with an inflammatory reaction. Materials and Methods: One hundred and fifty patients were included in the study which were divided into GROUP-A, B, and C-50 patients each; those who underwent third molar removal under local anesthesia. Local anesthesia was obtained by inferior alveolar, lingual, long buccal, posterior superior alveolar, and greater palatal nerve block injections after first complain of pain, all patients were prescribed analgesics (Ketorolac-10 mg), (Tramadol-50 mg), (Flupirtine-100 mg), and antibiotics co-amoxiclav-625 mg) T. D. S in all the three groups A, B, C, respectively, for 5 days and the timing noted in the patients assessment sheet. The statistical analysis was done using SPSS Version 15.0 statistical analysis software. Results: The flupirtine group has early onset and also had minimum side effects. All the groups showed similar trend in change in pain score from 3 h. P. O to different time intervals. It was observed the pain score increased significantly till 6 h. Post operative a decreased trend was found at 24 h, 48 h, 78 h, after 6 h. and this change was found to be statistically significant for all three groups. Conclusion: Flupirtine had faster onset and comparable pain management profile as compared to tramadol, it also had minimum side effects, hence the use of flupirtine might be recommended for postoperative pain management in cases undergoing third molar surgery. [ABSTRACT FROM AUTHOR]

In the present study, we developed a simple, sensitive, precise, and accurate liquid chromatography-tandem mass spectrometric (LC-MS/MS) method and validated such approach for simultaneous determination of flupirtine and its active metabolite D-13223 in human plasma. The flupirtine, D-13223, and stable isotope internal standard (IS) were extracted from plasma samples by liquid-liquid extraction and chromatographed on a C18 column with a mobile phase consisting of acetonitrile-water-ammonia (55:45:0.1, v/v/v) at a flow rate of 0.25 mL/min. Detection was performed on a triple quadrupole tandem mass spectrometer with an electrospray ionization source (ESI) by multiple reaction monitoring (MRM) in positive ion mode. The linear calibration curves were obtained within the concentration range of 10.00-2000.00 ng/mL for flupirtine and 2.00-400.00 ng/mL for D-13223. The intra- and inter-run RSD, calculated from quality control (QC) samples, was less than 9.26% for flupirtine and D-13223. The accuracy was -5.80%-3.31% for flupirtine and D-13223. The extraction recoveries of flupirtine, D-13223, and their IS were all between 88.3%-97.2%. The method was successfully applied to investigate the pharmacokinetic profiles of flupirtine and its active metabolite D-13223 in human plasma following peroral administration of 100 mg flupirtine maleate capsules in healthy male Chinese volunteers. [ABSTRACT FROM AUTHOR]

Voltage-gated Kv7 (KCNQ family) K+ channels are expressed in many neuronal populations and play an important role in regulating membrane potential by generating a hyperpolarizing Kþ current and decreasing cell excitability. However, the role of KV7 channels in the neural regulation of intestinal epithelial Cl- secretion is not known. Cl- secretion in mouse distal colon was measured as a function of short-circuit current (ISC), and pharmacological approaches were used to test the hypothesis that activation of KV7 channels in enteric neurons would inhibit epithelial Cl- secretion. Flupirtine, a nonselective KV7 activator, inhibited basal Cl- secretion in mouse distal colon and abolished or attenuated the effects of drugs that target various components of enteric neurotransmission, including tetrodotoxin (NaV channel blocker), veratridine (NaV channel activator), nicotine (nicotinic acetylcholine receptor agonist), and hexamethonium (nicotinic antagonist). In contrast, flupritine did not block the response to epithelium-targeted agents VIP (endogenous VPAC receptor ligand) or carbachol (nonselective cholinergic agonist). Flupirtine inhibited Cl- secretion in both full-thickness and seromuscular-stripped distal colon (containing the submucosal, but not myenteric plexus) but generated no response in epithelial T84 cell monolayers. KV7.2 and KV7.3 channel proteins were detected by immunofluorescence in whole mount preparations of the submucosa from mouse distal colon. ICA 110381 (KV7.2/7.3 specific activator) inhibited Cl- secretion comparably to flupirtine. We conclude that KV7 channel activators inhibit neurally driven Cl- secretion in the colonic epithelium and may therefore have therapeutic benefit in treating pathologies associated with hyperexcitable enteric nervous system, such as irritable bowel syndrome with diarrhea (IBS-D). [ABSTRACT FROM AUTHOR]

Since 1955, several alkyl‐carbamates have been developed for the treatment of anxiety and epilepsy, including meprobamate, flupirtine, felbamate, retigabine, carisbamate, and cenobamate. They have each enjoyed varying levels of success as antiseizure drugs; however, they have all been plagued by the emergence of serious and sometimes life‐threatening adverse events. In this review, we compare and contrast their predominant molecular mechanisms of action, their antiseizure profile, and where possible, their clinical efficacy. The preclinical, clinical, and mechanistic profile of the prototypical γ‐aminobutyric acidergic (GABAergic) modulator phenobarbital is included for comparison. Like phenobarbital, all of the clinically approved alkyl‐carbamates share an ability to enhance inhibitory neurotransmission through modulation of the GABAA receptor, although the specific mechanism of interaction differs among the different drugs discussed. In addition, several alkyl‐carbamates have been shown to interact with voltage‐gated ion channels. Flupirtine and retigabine share an ability to activate K+ currents mediated by KCNQ (Kv7) K+ channels, and felbamate, carisbamate, and cenobamate have been shown to block Na+ channels. In contrast to other alkyl‐carbamates, cenobamate seems to be unique in its ability to preferentially attenuate the persistent rather than transient Na+ current. Results from recent randomized controlled clinical trials with cenobamate suggest that this newest antiseizure alkyl‐carbamate possesses a degree of efficacy not witnessed since felbamate was approved in 1993. Given that ceno‐bamate's mechanistic profile is unique among the alkyl‐carbamates, it is not clear whether this impressive efficacy reflects an as yet undescribed mechanism of action or whether it possesses a unique synergy between its actions at the GABAA receptor and on persistent Na+ currents. The high efficacy of cenobamate is, however, tempered by the risk of serious rash and low tolerability at higher doses, meaning that further safety studies and clinical experience are needed to determine the true clinical value of cenobamate. [ABSTRACT FROM AUTHOR]

A simple, sensitive, accurate new analytical method based on colorimetric determination was developed and validated for the estimation of Flupirtine maleate in pure and pharmaceutical dosage forms. Flupirtine reacts with Sodium nitrite (NaNO2) and Hydrochloric acid (HCl) to form a yellow-colored compound and colored complex which can be estimated by colorimetrically. The color of the solutions has measured the absorbance at γmax 411 nm. Beers law was followed in the range of 10-50µg/ml respectively. The correlation coefficient was found to be 0.9998. LOD and LOQ were determined and found to be 0.103 µg/ml and 0.318 µg/ml respectively. The recovery studies were performed. The percent recovery was found to be 99.4 ± 1. The method was conducted and validated as per ICH guidelines. The proposed method was found to be precise, accurate and successfully validated for the routine analysis of Flupirtine maleate in bulk drug and in the formulation. [ABSTRACT FROM AUTHOR]

Livia Puljak1,2 1Laboratory for Pain Research, University of Split School of Medicine, Split, Croatia; 2Department for Development, Research and Health Technology Assessment, Agency for Quality and Accreditation in Health Care and Social Welfare, Zagreb, CroatiaOn October 16, 2017 in the Journal of Pain Research, a randomized controlled trial (RCT) comparing efficacy and safety of flupirtine versus piroxicam in postoperative pain in patients undergoing lower limb surgery was published.1 However, this paper fails to report important information. Author’s reply Sowmya Chinnaiyan,1 Narayana Sarala,1 Heddur Shanthappa Arun21Department of Pharmacology, 2Department of Orthopedics, Sri Devaraj Urs Medical College, Sri Devaraj Urs Academy of Higher Education and Research, Kolar, Karnataka, India We thank Livia Puljak for the valuable insights on the article titled “A comparative study of efficacy and safety of flupirtine versus piroxicam in postoperative pain in patients undergoing lower limb surgery” published in the Journal of Pain Research. The concerns highlighted in the Letter to the Editor have been answered.View the original paper by Chinnaiyan and colleagues.

Introduction: Gout arthritis is an inflammatory disease characterized by severe acute pain. The goal of pharmacological gout arthritis treatments is to reduce pain, and thereby increase the patient's quality of life. The Kv7/M channel activators retigabine and flupirtine show analgesic efficacy in animal models of osteoarthritic pain. We hypothesized that these drugs may also alleviate gout arthritis pain. Objective: To determine the effects of retigabine and flupirtine on pain behavior associated with monosodium urate (MSU)-induced gout arthritis. Methods: The gout arthritis model was established with an intra-articular injection of MSU into the right ankle joint, animals were treated with retigabine or flupirtine, and pain-related behaviors were assessed. Results: Retigabine and flupirtine significantly increased the mechanical threshold and prolonged the paw withdrawal latency in a rat model of gout arthritis pain in a dose-dependent manner. The antinociceptive effects of retigabine and flupirtine were fully antagonized by the Kv7/M channel blocker XE991. Conclusion: Retigabine and flupirtine showed antinociceptive effects for MSU-induced gout pain at different times during pain development. [ABSTRACT FROM AUTHOR]

In spite of single nanomaterials, nanocomposites have come to be the superior modifying materials for electrochemical sensing. Herein, the highly sophisticated and sensitive voltammetric sensor of polypyrrole/cerium oxide/glassy carbon electrode (Ppyr/CeO2/GCE) has been fabricated for the electrochemical analysis of flupirtine maleate (FPM). Prior to the fabrication, the synthetic Ppyr/CeO2 material and its constituents viz., Ppyr and CeO2 were spectrally characterized by FTIR, XRD, and SEM to confirm the successful synthesis. After the fabrication of the Ppyr/CeO2/GCE sensor, it together with its corresponding forms i.e., CeO2/GCE and Ppyr/GCE including bare GCE was characterized by voltammetry and electrochemical impedance spectroscopy (EIS). The electrode characteristics such as charge transfer resistance, heterogeneous electron transfer (HET) rate constant, ( k eff 0 ) and surface area suggest that the designed electrochemical sensor has got the conductivity (sensitivity) par excellence as compared to CeO2/GCE, Ppyr/GCE and bare GCE. The fabricated probe after characterization was optimized for the detection of the FPM by voltammetry and found to show a direct correlation between the oxidation current and the FPM concentration varying from 100 ng mL−1 to 500 ng mL−1 having correlation coefficient (r2) of 0.9940. By measuring the calibration curve, the fabricated Ppyr/CeO2/GCE sensor was found to reach the minimum limit of detection (LOD) i.e., 26.76 ng mL−1 and minimum limit of quantification (LOQ) i.e., 89.20 ng mL−1, for FPM, thereby showing the sensitivity par excellence in terms of conductivity. Fabrication of Ppyr/CeO2/GCE voltammetric sensor [ABSTRACT FROM AUTHOR]

Yanfang Liu, Hua Huo, Zhibo Zhao, Wenli Hu, Yujia Sun, Yunbiao Tang Technical Center for Clinical Pharmacy, Department of Drug Clinical Trail Management Agency, General Hospital of Shenyang Military Area Command, Shenyang, China Aim: This study developed a high-performance liquid chromatography–tandem mass spectrometry method to simultaneously determine the concentrations of flupirtine and its major active metabolite D-13223 in human plasma in order to assess the bioequivalence (BE) of two flupirtine maleate capsules among healthy male Chinese volunteers under fasting and fed conditions. Materials and methods: There were two single-center, randomized, single-dose, open-label, laboratory-blinded, two-period, cross-over studies which included 24 healthy male Chinese volunteers under fasting and fed conditions, respectively. Plasma samples were collected prior to and up to 48 h after dosing. The concentrations of flupirtine and its major active metabolite D-13223 in plasma samples were determined by a validated method, that is, high-performance liquid chromatography coupled with a tandem mass spectrometry detector. Pharmacokinetic metrics of area from time zero to the last measurable concentration (AUC0-t), area under the plasma concentration–time curve from administration to infinite time (AUC0-∞), and Cmax were used for BE assessment. Results: Forty-eight healthy volunteers who met the criteria were enrolled and completed the study. According to the observation of vital signs and laboratory measurement, no volunteers had any adverse reactions. Under fasting condition, the geometric mean ratios (90% CI) of the test/reference drug for flupirtine were 103.0% (98.1%–108.2%) for AUC0-t, 102.9% (98.2%–107.9%) for AUC0-∞, and 97.0% (85.9%–109.5%) for Cmax. Under fed condition, the geometric mean ratios (90% CI) of the test/reference drug for flupirtine were 101.7% (98.4%–105.1%) for AUC0-t, 101.6% (98.5%–104.8%) for AUC0-∞, and 103.5% (94.7%–113.0%) for Cmax. The difference between test and reference formulations, Tmax, was not statistically significant. The 90% CIs of the test/reference AUC ratio and Cmax ratio of D-13223 were also within the acceptance range for BE both under fasting and fed conditions. Conclusion: The two formulations of flupirtine maleate capsule were bioequivalent (the test and the reference products) under fasting and fed conditions, and thus both can be used interchangeably in the clinical setting. Keywords: flupirtine, D-13223, LC–MS/MS

Sowmya Chinnaiyan,1 Narayana Sarala,1 Heddur Shanthappa Arun2 1Department of Pharmacology, 2Department of Orthopaedics, Sri Devaraj Urs Medical College, Sri Devaraj Urs Academy of Higher Education and Research, Kolar, Karnataka, India Background: Effective control of pain postoperatively is essential in providing enhanced patient care and a cost-effective hospital stay. Though many treatment modalities exist for postoperative pain management in orthopedic surgeries they are often accompanied by adverse effects. This study was carried out to assess the efficacy of flupirtine and piroxicam in postoperative pain reduction using visual analog scale (VAS) score. Materials and methods: An open-label, parallel group, comparative study was conducted on patients undergoing lower limb orthopedic surgery, randomized into two groups of 38 patients each. They received either flupirtine 100 mg or piroxicam 20 mg 6 hours after surgery and then twice daily orally for 5 days. Pain was measured using VAS score, total pain relief score (TOTPAR24), and patient satisfaction score (PSS); the other scales used were behavioral pain assessment scale (BPAS) and functional activity score (FAS). Rescue medication used was tramadol 100 mg intravenously. WHO causality scale was used for assessing adverse effects. Descriptive and inferential statistics were used for assessment of various parameters. Results: A total of 76 patients with mean ± standard deviation age of 35.08±10.3 years were recruited; 34 in the flupirtine and 37 in the piroxicam groups completed the study. Patients in both groups were comparable in baseline characteristics. Flupirtine and piroxicam reduced VAS score 48 hours postoperatively compared to baseline (p=0.006 and 0.001) and piroxicam produced significant reduction in pain at 8, 12, and 120 hours compared to flupirtine (p=0.028, 0.032, 0.021). TOTPAR24 and PSS at 24 hours were comparable between the treatments. BPAS scores at 24 hours were reduced significantly in patients receiving either drug (p=0.001). FAS improved at 72 hours in patients receiving piroxicam. Adverse effects were similar with both the medications. Conclusion: Flupirtine and piroxicam reduced pain effectively but the onset of pain relief was earlier with piroxicam. Keywords: postoperative pain, flupirtine, piroxicam, orthopedic surgeries, postoperative analgesia

• SFC enables simultaneous quantification of acidic and basic metabolites of flupirtine. • Polysaccharide-phases show higher selectivity than traditional Si-modifications. • Specific retention of flupirtine on Lux-Amylose-2 involves halogen and π-π-bonding. • Validated SFC (guideline-conform) is suitable for clinical metabolism studies. • Oxidative degradation products comprise up to 25% of renal flupirtine elimination. Supercritical fluid chromatography (SFC) holds the potential to become an orthogonal method to HPLC/UHPLC in xenobiotic metabolism studies, due to its outstanding capacity to simultaneously separate highly similar (as HPLC) and physicochemically different analytes (problematic using HPLC). Paucity of guideline-conform validation, however, has been a major obstacle to clinical application of SFC, even in cases where biotransformation yields chemically dissimilar metabolites that require more than one HPLC method for comprehensive analysis. Here, a method based on supercritical fluid chromatography coupled to single quadrupole MS detection was developed to simultaneously quantify the divisive analgesic flupirtine and its acidic and basic metabolites, represented by 4-fluorohippuric acid (4-FHA) and the active metabolite D-13223 respectively, using custom-made synthetic internal standards. Experimental data on the fundamental retention mechanisms under supercritical conditions, indicating the importance of halogen and π-π-bonding for specific retention on polysaccharide-based stationary-phases, is discussed. Compared to previous HPLC methods, the novel method offers higher versatility in terms of the target metabolite range (addressing both acidic and basic metabolites within a singular method), faster analysis (7.5 min), and compliance with green chemistry principles. Validation was performed according to EMA criteria on bioanalytical method validation, demonstrating selectivity, carry-over, calibration curve parameters (LLOQ, range, and linearity), within- and between-run accuracy and precision, dilution integrity, matrix effect and stability. For proof-of-concept, the SFC method was applied to clinical samples of human urine obtained after single intravenous (100 mg), single oral (100 mg), and repeated oral administration (400 mg). Flupirtine, D-13223, and 4-FHA could be quantified, shedding light on the extent of oxidative flupirtine metabolism in humans in the context of the unresolved biotoxification that has led to the withdrawal of specific neuronal K V 7 openers. [ABSTRACT FROM AUTHOR]

Background: Kv7 neuronal channels are recognized as a potential drug target for anxiolytic effects. We hypothesize that flupirtine as a potassium channel opener would effectively reduce the preoperative anxiety of patients undergoing craniotomy procedure. Methods: In prospective-double-blinded fashion, 124 counseled patients were randomized to receive 5 sequential doses of capsule flupirtine 100 mg (F Group) or physically similar starch capsules (C Group), at 12 h intervals during preoperative hospitalization. Primary outcome included various aspects of patient anxiety measured by visual analog scale (VAS) just before preoperative counseling and 2 h after the completion of drug regimen under trial. Statistical tool included Mann–Whitney U-test and Wilcoxon signed rank test. Results: Baseline VAS scores were higher for fear of surgical harm, being at the mercy of medical staff, and not awakening after surgery. A significant decline in VAS scores was observed after the completion of drug regime, but to a higher extent in flupirtine-treated patients; it achieved statistical significance in comparison to Group C. No side effects were observed in any patient. Conclusion: Flupirtine is a useful premedication in conjunction with behavioral therapy to alleviate patient anxiety during the preoperative period.

Central nervous system inflammation and neurodegeneration are the pathophysiological hallmarks of multiple sclerosis (MS). While inflammation can readily be targeted by current disease modifying drugs, neurodegeneration is by far less accessible to treatment. Based on suggested additional neuroprotective capacities of the orally available non-opioid and centrally acting analgesic drug flupirtine maleate we hypothesized that treatment with flupirtine maleate might be beneficial in MS patients. The flupirtine as oral treatment in multiple sclerosis (FLORIMS) study was a multi-center, randomized and stratified, placebo-controlled double-blind phase II trial to investigate safety and efficacy in terms of clinical and radiographical activity of flupirtine maleate (300 mg per day) given orally for 12 months, add-on to interferon beta 1b subcutaneously in patients with relapsing remitting MS. Due to a substantial delay in recruitment, enrolment of patients was prematurely terminated after randomization of only 30 of the originally planned 80 patients. Of these, 24 regularly terminated study after 12 months of treatment. Data were analyzed as originally planned. Treatment with flupirtine maleate was overall well tolerated. We observed moderate and asymptomatic elevations of liver enzymes in several cases but no overt hepatotoxicity. Neither the intention to treat nor the per protocol analysis revealed any significant treatment effects of flupirtine maleate with respect to occurrence of MS relapses, disability progression, or development of new lesions on cranial MRI. However, substantial methodological limitations need to be considered when interpreting these results. In conclusion, the results of the FLORIMS study neither add further evidence to nor argue against the hypothesized neuroprotective or disease modifying effects of flupirtine maleate in MS.

Objectives: This report characterizes flupirtine prescribing patterns before and after the implementation of risk minimization measures (RMM) in Germany as a complementary analysis to support previous study findings. Methods: A retrospective analysis was conducted using a patient-level longitudinal prescription database (IMS LRx) in Germany. The study population included patients who were prescribed flupirtine-containing products. One-year periods before (2012) and after (April 2015-March 2016) RMM implementation were assessed for the following measures: flupirtine use of up to two weeks, flupirtine use when other analgesics are contraindicated and concomitant use of drugs with a known potential to induce liver injury. Results: The number of flupirtine users decreased by 41.0% from 248,738 patients in the pre-RMM implementation period to 146,764 in the post-implementation period. The proportion of patients prescribed flupirtine for up to 14 days increased significantly by 22.7%, from 67.9% to 90.6% in the pre- to post-implementation periods, respectively. Over half the patients received long-term medications for conditions contraindicated with the use of other analgesics within 12 months prior to the first flupirtine prescription in the pre- and post-implementation periods (57.1% and 52.3%, respectively). Concomitant prescriptions of drugs with known potential hepatotoxic effects were recorded in 36.6% and 34.2% of flupirtine prescriptions during the pre- and post-implementation periods, respectively. Conclusions: While physicians generally restricted flupirtine prescriptions to the short-term treatment duration recommended in the labeling, the other labeling recommendations were not as stringently adopted. Findings of this investigation support a previous study conducted in an electronic medical record database. [ABSTRACT FROM AUTHOR]

Neuropathic pain conditions severely and chronically affect the quality of life in a large human population, but the pain conditions are not adequately managed due to poor understanding of their underlying mechanisms. There is a pressing need for further research into this field to help develop effective and nonaddictive medications to treat neuropathic pain. This article first describes general clinical classification of pain, types and symptoms of neuropathic pain, and current practices of clinical management for neuropathic pain. This is followed by a discussion of various cellular and molecular mechanisms responsible for the development and maintenance of neuropathic pain. In this review, we highlight the loss of function of Kv7 voltage-gated potassium as a mechanism of neuropathic pain and the potential use of Kv7 channel activator as subsequent treatment. [ABSTRACT FROM AUTHOR]

Objective: To provide further evidence of dependence on non-opioid analgesics (NOAs).Methods: Post-hoc-analysis of a cross-sectional study of a ≥ -65-year-old non-demented German general hospital population. Four hundred in-patients (75 ± 6.4 years; 63% females) were included and screened for current and past dependence on NOAs using a structured interview (SKID-I) based on DSM-IV-TR. The addiction section of SKID-I was expanded to the following NOAs: gabapentinoids, acetaminophen, metamizole, flupirtine, and non-steroidal anti-inflammatory drugs (NSAIDs).Results: We found twenty-eight seniors (7%) who fulfilled the criteria for a NOA-dependence. Of whom, twenty-four and four patients were currently dependent and in remission, respectively. According to SKID-I, twenty-one (75%) patients were mildly, five patients (17.9%) moderately, and two (7.1%) patients severely dependent on NOAs. All patients showed at least one sign of physical dependence (tolerance and/or withdrawal symptoms) and most of them reported additional behavioral dependence symptoms. Whereas there was one dependence on gabapentinoids or acetaminophen only, NSAIDs and metamizole were involved in the majority of cases (n = 25; 89.3%). Of note, ten (35.7%) seniors had a de-novo substance dependence exclusively on NOAs - including 2 females with signs of a de-novo dependence on metamizole, a NOA which yet has been not in the focus of addiction medicine.Conclusion: This cross-sectional study provides further evidence of the existence of a physical and behavioral dependence on NOAs including NSAIDs. Furthermore, preliminary evidence of a de-novo dependence on metamizole is provided which needs further verification. [ABSTRACT FROM AUTHOR]

Objective: In response to safety concerns, risk minimization measures (RMM) for flupirtine were implemented in Europe in 2013 to reduce hepatotoxicity risk. This study aims to characterize compliance and prescribing practices of flupirtine before and after RMM implementation.Research design and methods: A retrospective pre-post design cohort study was conducted in the outpatient setting using a longitudinal electronic medical record database in Germany. The study population included patients who initiated flupirtine. One-year pre- and post-implementation periods were assessed.Main outcome measures: Six RMM elements were evaluated, including indication of acute pain, use for maximum of 2 weeks, use when other analgesics are contraindicated, no pre-existing liver disease or alcohol abuse, no concomitant drug induced liver injury, and weekly liver function tests.Results: The number of flupirtine users decreased by 34.4% from 18,291 in the pre-implementation period (2012) to 12,000 in the post-implementation period (April 2015 to March 2016). Elements of RMM with substantial improvement included flupirtine prescription duration, where the proportion of patients with duration ≤14 days increased significantly by 16.5% from 74.8% to 91.3% in the pre- and post-implementation periods, respectively. RMM with a moderate-to-high degree of compliance during the post-implementation period, although with a very small or no change from the pre- implementation period, included restriction of flupirtine prescribing to patients with acute pain when other analgesics are contraindicated, and avoiding use in patients with either pre-existing liver disease or concomitant drugs known to have a potential hepatotoxic effect. Weekly liver function tests had a low degree of compliance.Conclusions: These findings demonstrate that, while physicians restricted flupirtine prescriptions to short-term use in the target population of acute pain, not all drug labeling elements were followed to the same extent in routine practice. [ABSTRACT FROM AUTHOR]

Central nervous system inflammation and neurodegeneration are the pathophysiological hallmarks of multiple sclerosis (MS). While inflammation can readily be targeted by current disease modifying drugs, neurodegeneration is by far less accessible to treatment. Based on suggested additional neuroprotective capacities of the orally available non-opioid and centrally acting analgesic drug flupirtine maleate we hypothesized that treatment with flupirtine maleate might be beneficial in MS patients. The fl upirtine as or al treatment i n m ultiple s clerosis (FLORIMS) study was a multi-center, randomized and stratified, placebo-controlled double-blind phase II trial to investigate safety and efficacy in terms of clinical and radiographical activity of flupirtine maleate (300 mg per day) given orally for 12 months, add-on to interferon beta 1b subcutaneously in patients with relapsing remitting MS. Due to a substantial delay in recruitment, enrolment of patients was prematurely terminated after randomization of only 30 of the originally planned 80 patients. Of these, 24 regularly terminated study after 12 months of treatment. Data were analyzed as originally planned. Treatment with flupirtine maleate was overall well tolerated. We observed moderate and asymptomatic elevations of liver enzymes in several cases but no overt hepatotoxicity. Neither the intention to treat nor the per protocol analysis revealed any significant treatment effects of flupirtine maleate with respect to occurrence of MS relapses, disability progression, or development of new lesions on cranial MRI. However, substantial methodological limitations need to be considered when interpreting these results. In conclusion, the results of the FLORIMS study neither add further evidence to nor argue against the hypothesized neuroprotective or disease modifying effects of flupirtine maleate in MS. [ABSTRACT FROM AUTHOR]

CLN3 disease is a fatal neurodegenerative disorder affecting children. Hallmarks include brain atrophy, accelerated neuronal apoptosis, and ceramide elevation. Treatment regimens are supportive, highlighting the importance of novel, disease-modifying drugs. Flupirtine and its new allyl carbamate derivative (compound 6) confer neuroprotective effects in CLN3-deficient cells. This study lays the groundwork for investigating beneficial effects in Cln3Δex7/8 mice. WT/Cln3Δex7/8 mice received flupirtine/compound 6/vehicle for 14 weeks. Short-term effect of flupirtine or compound 6 was tested using a battery of behavioral testing. For flupirtine, gene expression profiles, astrogliosis, and neuronal cell counts were determined. Flupirtine improved neurobehavioral parameters in open field, pole climbing, and Morris water maze tests in Cln3Δex7/8 mice. Several anti-apoptotic markers and ceramide synthesis/degradation enzymes expression was dysregulated in Cln3Δex7/8 mice. Flupirtine reduced astrogliosis in hippocampus and motor cortex of male and female Cln3Δex7/8 mice. Flupirtine increased neuronal cell counts in male mice. The newly synthesized compound 6 showed promising results in open field and pole climbing. In conclusion, flupirtine improved behavioral, neuropathological and biochemical parameters in Cln3Δex7/8 mice, paving the way for potential therapies for CLN3 disease.

Background and Aims: Flupirtine maleate is a centrally acting, non-opioid analgesic with unique muscle relaxant properties as compared to common analgesics. The aim of this study was to compare post-operative analgesic efficacy of flupirtine maleate and ibuprofen in patients undergoing gynaecological ambulatory surgeries. Methods: This prospective, randomised controlled study was conducted in 60 women of American Society of Anesthesiologists physical status I/II, 18-70 years of age and scheduled to undergo gynaecological ambulatory surgeries. The participants were randomised to receive either 100 mg oral flupirtine maleate (group flupirtine, n = 30) or 800 mg oral ibuprofen (group ibuprofen, n = 30), 1 h prior to surgery and then every 8 h for 48 h. Verbal Numerical Rating Scale (VNRS) on movement was assessed at 0, 2, 4, 6 and 8 h following surgery. Following discharge from hospital, the patients were interviewed telephonically at 12, 24 and 48 h post-operatively. VNRS was statistically analysed using Mann-Whitney test. Results: VNRS on movement was statistically reduced at 2 h after surgery (P = 0.04) in group flupirtine as compared to group ibuprofen. The analgesic efficacy was similar in both the groups at 4, 6, 8, 12, 24 and 48 h after surgery. The satisfaction scores at 24 and 48 h post-operatively were superior in group flupirtine as compared to group ibuprofen (P < 0.001). Conclusion: Analgesic efficacy of flupirtine maleate was comparable with ibuprofen in patients in ambulatory gynaecological patients up to 48 h postoperatively with superior satisfaction scores.

Graphical abstract Abstract The use of flupirtine, an analgesic, has been restricted in European countries because it causes liver injury in rare cases. Flupirtine is primarily metabolized to D-13223, an acetylamino form. In the process of D-13223 formation, it has been hypothesized that a reactive metabolite is formed which may be involved in flupirtine hepatotoxicity. The purpose of this study was to identify the potential reactive metabolite and the responsible enzymes in the human liver to get a clue to the mechanism of hepatotoxicity. Using recombinant enzymes, we found that D-13223 was formed from flupirtine via hydrolysis by carboxylesterase 2 (CES2) and subsequent acetylation by N -acetyltransferase (NAT) 2. A conjugate of N -acetyl- l -cysteine (NAC), a nucleophile, was detected by incubation of flupirtine with CES2, and the conjugate formation in human liver microsomes was inhibited by CES2 inhibitors, indicating that a reactive metabolite, which may be a quinone diimine, was produced in the process of CES2-mediated hydrolysis of flupirtine. The formation of the NAC conjugate in liver S9 samples from NAT2 slow acetylators was significantly higher than that from NAT2 rapid/intermediate acetylators, indicating that NAT2 could function as a detoxification enzyme for flupirtine. CES2-overexpressing HepG2 cells showed remarkable lactate dehydrogenase leakage under flupirtine treatment, while no cytotoxicity was observed in control cells, suggesting that the reactive metabolite formed by CES2-mediated hydrolysis of flupirtine would be a trigger of hepatotoxicity. NAT2 slow acetylators with high CES2 activity could be highly susceptible to flupirtine-induced liver injury. [ABSTRACT FROM AUTHOR]

Flupirtine is an amino pyridine derivative that functions as a centrally acting non-opioid, non-steroidal analgesic. It is a selective neuronal potassium channel opener that also has NMDA receptor antagonist properties. Its muscle relaxant properties make it popular for back pain and other orthopedics uses. In the present investigation, recently developed mixed hydrotropic solid dispersion technology precludes the use of organic solvent and also decreases the individual concentration of hydrotropic agents, simultaneously decreasing their toxic potential. Mixed-hydrotropic solubilisation technique is the experience to increase the solubility of poorly water soluble drugs in the aqueous solution containing blends of hydrotropic agents, which may give synergistic enhancement effect on solubility of poorly water-soluble drugs and to reduce concentrations of each individual hydrotropic agent to minimize their toxic effects due to high concentration of hydrotropic agents. The Flupirtine loaded solid dispersion was prepared by a solvent evaporation technique using sodium benzoate and a niacinamide hydrotropic mixture. The prepared solid dispersions were valuated regarding their solubility, mean particle size, in-vitro drug release. The prepared solid dispersions were found very stable (chemically). The superior dissolution rate due to its reduced particle size may have contributed to the increased oral bioavailability. This study demonstrated that mixed-solvency may be an alternative approach for poorly soluble drugs to improve their solubility and oral bioavailability. [ABSTRACT FROM AUTHOR]

Context: Kv7 potassium channels are expressed in several types of smooth muscles and could mediate physiological responses in the tissues expressed. Flupirtine is an analgesic that acts by opening Kv7 potassium channels. It has been shown to inhibit the contractility of several types of isolated smooth muscle. Aims: This study investigated the ability of flupirtine to inhibit the spontaneous contractility of isolated distal caprine (goat) ureter. Settings and Design: Spontaneous contractility of the isolated goat ureter was recorded using a physiograph. Materials and Methods: The ability of 1, 3, 10, 30, and 90 μM concentrations of flupirtine maleate to inhibit the spontaneous contractility of isolated distal goat ureter was investigated. The ability of the nonspecific potassium channel blocker 4-aminopyridine (4-AP; 1 mM) and the specific Kv7 channel blocker XE-991 (100 μM) to reverse the inhibitory effect of flupirtine on ureteric contractility was also investigated. Statistical Analysis Used: Both parametric and nonparametric statistical tests were used. Results: At 10, 30, and 90 μM concentrations, flupirtine significantly inhibited the spontaneous contractility of the isolated goat ureter. The EC50 of flupirtine for a contact period of 10 min was 17.7 μM. The inhibitory effect of flupirtine on ureteric contractility was significantly reversed by 4-AP and XE-991. Conclusions: Flupirtine inhibits the spontaneous contractility of the isolated goat ureter by opening Kv7 channels. [ABSTRACT FROM AUTHOR]

A validated method for quantitative determination of flupirtine in human blood plasma using liquid chromatography combined with tandem mass spectrometry (HPLC-MS/MS) was proposed. Biological samples were prepared by precipitating proteins using MeOH. The chromatographic separation used a Zorbax Eclipse Plus C18 column with gradient elution. A Shimadzu 8040 triple quadrupole mass spectrometer in multiple-reaction-monitoring mode (+MRM) with chemical ionization at atmospheric pressure (APCI) was used to determine the molecular ion of flupirtine with m/z 305.2. Acalibration curve for flupirtine was linear (R = 0.994) in the concentration range 25 - 2,500 ng/mL with a lower detection limit of 25 ng/mL. Validation of the method indicated that it was highly sensitive, specific, accurate, and precise and that the analyte was stable. The method was successfully applied to comparative pharmacokinetic studies of drugs containing flupirtine. [ABSTRACT FROM AUTHOR]

A sensitive and rapid LC-MS/MS method was developed and validated for the simultaneous quantitation of five selective KCNQ channel openers, namely ICA-27243, ML-213, PF-05020182, SF-0034 and flupirtine in mice plasma as per regulatory guideline. The analytes and the internal standard (IS; flupirtine-d4) were extracted from 50 µL mice plasma by liquid-liquid extraction, followed by chromatographic separation using an Atlantis C18 column with an isocratic mobile phase comprising 0.2% formic acid: acetonitrile (20:80, v/v) at a flow rate of 0.6 mL min−1 within 2.5 min. Detection and quantitation was done by multiple reaction monitoring on a triple quadrupole mass spectrometer following the transitions: m/z 268.9 → 140.8, 258.1 → 95.1, 367.2 → 269.1, 322.2 → 248.2, 305.7 → 196.4 and 309.1 → 196.1 for ICA-27243, ML-213, PF-05020182, SF-0034, flupirtine and the IS, respectively, in the positive ionization mode. The calibration curves were linear from 1.00 to 2008 ng mL−1 for all the analytes with r2 ≥ 0.99. The intra- and inter-batch accuracy and precision (% CV) across quality controls varied from 90.0 to 113 and 2.64 to 13.0; 93.8 to 114 and 3.15 to 14.9%, respectively, for all the analytes. Analytes were found to be stable under different stability conditions. The method was applied to a pharmacokinetic study in mice. [ABSTRACT FROM AUTHOR]

Aim: This study developed a high-performance liquid chromatography-tandem mass spectrometry method to simultaneously determine the concentrations of flupirtine and its major active metabolite D-13223 in human plasma in order to assess the bioequivalence (BE) of two flupirtine maleate capsules among healthy male Chinese volunteers under fasting and fed conditions. Materials and methods: There were two single-center, randomized, single-dose, open-label, laboratory-blinded, two-period, cross-over studies which included 24 healthy male Chinese volunteers under fasting and fed conditions, respectively. Plasma samples were collected prior to and up to 48 h after dosing. The concentrations of flupirtine and its major active metabolite D-13223 in plasma samples were determined by a validated method, that is, high-performance liquid chromatography coupled with a tandem mass spectrometry detector. Pharmacokinetic metrics of area from time zero to the last measurable concentration (AUC0-t), area under the plasma concentration-time curve from administration to infinite time (AUC0-∞), and Cmax were used for BE assessment. Results: Forty-eight healthy volunteers who met the criteria were enrolled and completed the study. According to the observation of vital signs and laboratory measurement, no volunteers had any adverse reactions. Under fasting condition, the geometric mean ratios (90% CI) of the test/reference drug for flupirtine were 103.0% (98.1%-108.2%) for AUC0-t, 102.9% (98.2%-107.9%) for AUC0-∞, and 97.0% (85.9%-109.5%) for Cmax. Under fed condition, the geometric mean ratios (90% CI) of the test/reference drug for flupirtine were 101.7% (98.4%-105.1%) for AUC0-t, 101.6% (98.5%-104.8%) for AUC0-∞, and 103.5% (94.7%-113.0%) for Cmax. The difference between test and reference formulations, Tmax, was not statistically significant. The 90% CIs of the test/reference AUC ratio and Cmax ratio of D-13223 were also within the acceptance range for BE both under fasting and fed conditions. Conclusion: The two formulations of flupirtine maleate capsule were bioequivalent (the test and the reference products) under fasting and fed conditions, and thus both can be used interchangeably in the clinical setting. [ABSTRACT FROM AUTHOR]

Background: Functional endoscopic sinus surgery (FESS) is the mainstay therapeutic management for nasal pathologies. We evaluated flupirtine, a centrally acting analgesic, for producing perfect perioperative conditions in FESS for adults in a day-care setting. Materials and Methods: Sixty-two patients (25-40 years) scheduled for FESS under general anesthesia were randomly divided into Group F (n = 31) receiving preoperative flupirtine (100 mg) and Group C (n = 31) receiving identical-looking placebo capsule per oral 60 min before induction of anesthesia. Perioperative Nasal bleeding and surgeon's satisfaction score during operation; amount and number of patients receiving fentanyl, propofol, and esmolol infusion for analgesia; maintenance of desired bispectral index (BIS) and deliberate hypotension, respectively. Postanesthesia Care Unit (PACU) and hospital stay, hemodynamic parameters, and side effects were all recorded for each patient. Results: Significantly, less number of patients and less dosage of esmolol were required (P = 0.0040 and 0.0001, respectively) in Group F as compared to that in Group C. Again, number of patients requiring fentanyl and dosage of the same drug was significantly lower in Group F. Dose of propofol for the maintenance of BIS was significantly lower in Group F. However, the duration of controlled hypotension was almost similar in both groups. Group F patients suffered significantly less nasal bleeding and surgeon's satisfaction score was also high in this group. Discharge time from PACU and hospital was similar between two groups without any appreciable side effects. Conclusion: Flupirtine as a premedication found to be providing more favorable perioperative hemodynamic conditions, analgesia and thus allowing less nasal bleeding as well as more surgeons' satisfaction score. [ABSTRACT FROM AUTHOR]

The KCNQ gene family, whose members encode Kv7 channels, belongs to the voltage-gated potassium (Kv) channel group. The roles of this gene family have been widely investigated in nerve and muscle cells. In the present study, we investigated several characteristics of Kv7.5, which is strongly expressed in the canine osteosarcoma cell line, CCL-183. Serum starvation upregulated Kv7.5 expression, and the Kv7 channel opener, flupirtine, attenuated cell proliferation by arresting cells in the G0/G1 phase. We also showed that Kv7.5 knockdown helps CCL-183 cells to proliferate. In an effort to find an endogenous regulator of Kv7.5, we used mithramycin A to reduce the level of the transcription factor Sp1, and it strongly inhibited the induction of Kv7.5 in CCL-183 cells. These results suggest that the activation of Kv7.5 by flupirtine may exert an anti-proliferative effect in canine osteosarcoma. Therefore, Kv7.5 is a possible molecular target for canine osteosarcoma therapy.

Flupirtine, a nonopioid analgesic drug, is effective in treating neonatal seizures. However, its brain delivery and pharmacokinetics are unknown in neonatal mammals. The purpose of this study was to determine the pharmacokinetics of flupirtine and the formation of its active metabolite D-13223 in various tissues such as brain in neonate animals. On postnatal day 7, rat pups received 25 mg/kg of flupirtine intraperitoneally. Liver; heart; kidney; lung; spleen; retina; serum; and brain regions hippocampus, cortex, and the remaining brain (devoid of cerebellum) were harvested up to 24-h postdosing. An LC-MS/MS assay was developed to quantify flupirtine and D-13223. Flupirtine was delivered to all tissues assessed, with the highest area under the concentration vs. time curve (AUC0⁻24h) in liver (488 µg·h/g tissue) and the lowest in spleen (82 µg·h/g tissue). Flupirtine reached the brain, including the hippocampus and cortex, within 1 h of dosing and persisted at 24 h. Flupirtine AUC in various brain regions was approximately 195 µg·h/g tissue. The half-life of flupirtine in various tissues ranged from 3.1 to 5.2 h. D-13223 was formed in vivo and detected in all tissues assessed, with the concentrations being the highest in the liver. Incubation of isolated neonatal rat liver, heart, kidney, lung, spleen, whole eye, serum, or whole brain with flupirtine for 3 h at 37 °C formed D-13223 in all tissues, except serum. D-13223 formation was the highest in isolated liver tissue. Tissue partition coefficients based on isolated tissue uptake correlated well with in vivo tissue:serum drug exposure ratios. Thus, flupirtine reaches the target brain tissues from the systemic route in neonatal rats, and brain tissue forms the active metabolite D-13223.

Background: Kv7 neuronal channels are recognized as a potential drug target for anxiolytic effects. We hypothesize that flupirtine as a potassium channel opener would effectively reduce the preoperative anxiety of patients undergoing craniotomy procedure. Methods: In prospective-double-blinded fashion, 124 counseled patients were randomized to receive 5 sequential doses of capsule flupirtine 100 mg (F Group) or physically similar starch capsules (C Group), at 12 h intervals during preoperative hospitalization. Primary outcome included various aspects of patient anxiety measured by visual analog scale (VAS) just before preoperative counseling and 2 h after the completion of drug regimen under trial. Statistical tool included Mann-Whitney U-test and Wilcoxon signed rank test. Results: Baseline VAS scores were higher for fear of surgical harm, being at the mercy of medical staff, and not awakening after surgery. A significant decline in VAS scores was observed after the completion of drug regime, but to a higher extent in flupirtine-treated patients; it achieved statistical significance in comparison to Group C. No side effects were observed in any patient. Conclusion: Flupirtine is a useful premedication in conjunction with behavioral therapy to alleviate patient anxiety during the preoperative period. [ABSTRACT FROM AUTHOR]

Voltage-gated type 7 K (K7 or KCNQ) channels regulate the contractility of various smooth muscles. With this study, we aimed to assess the role of K7 channels in the regulation of human detrusor contractility, as well as the gene and protein expression of K7 channels in this tissue. For these purposes, the isolated organ technique, RT-qPCR, and Western blot were used, respectively. XE-991, a selective K7 channel blocker, concentration-dependently contracted the human detrusor; mean EC and E of XE-991-induced concentration-response curve were 14.1 μM and 28.8 % of the maximal bethanechol-induced contraction, respectively. Flupirtine and retigabine, selective K7.2-7.5 channel activators, induced concentration-dependent relaxations of bethanechol-precontracted strips, with maximal relaxations of 51.6 and 51.8 % of the precontraction, respectively. XE-991 blocked the relaxations induced by flupirtine and retigabine. All five KCNQ genes were found to be expressed in the detrusor with KCNQ4 being the most expressed among them. Different bands, having sizes similar to some of reported K7.1, 7.4, and 7.5 channel subunit isoforms, were detected in the detrusor by Western blot with the K7.4 band being the most intense among them. In conclusion, K7 channels contribute to set the basal tone of the human detrusor. In addition, K7 channel activators significantly relax the detrusor. The K7.4 channels are probably the most important K7 channels expressed in the human detrusor. These data suggest that selective K7.4 channel activators might represent new pharmacological tools for inducing therapeutic relaxation of the detrusor. [ABSTRACT FROM AUTHOR]

Objective:Flupirtine is a non-opioid analgesic without antipyretic or antiphlogistic properties but with favorable tolerability in humans. This analgesic also exhibits neuroprotective activities. Furthermore, flupirtine antagonizes glutamateand NMDA-induced intracellular levels of Ca2+ and counteracts the effects of focal cerebral ischemia. Although flupirtine has been used to relieve pain caused by different diseases and clinical procedures, information on the safety and efficacy of flupirtine is limited. The present study was conducted to investigate the neuroprotective effects of flupirtine on U373 malignant glioma (MG) cell lines.Methods:Cell viability and cell cycle analysis was performed by MTT assay and flow cytometry, respectively.Results:Variations in the growth of U373 MG cells in 5 mM N-methyl-D-aspartate (NMDA), 1 mM flupirtine, and combined treatment indicated the antagonistic effects of NMDA and flupirtine on MG cell lines. The variation in the percentage of gated cell population in different cell cycle phases showed significant variations after 48 h of treatment.Conclusion:Flupirtine has neuroprotective effect of on U373 MG cells, which limits its use in the pain management of brain tumors. This property warrants further studies using animal models and large-scale clinical trials.