Nonpungent N-AVAM Capsaicin Analogues and Cancer Therapy.

Capsaicin displays robust growth-inhibitory activity in multiple human cancers. However, the feasibility of capsaicin as a clinically relevant anticancer drug is hampered by its adverse side effects. This concern has led to extensive research focused on the isolation and synthesis of second-generation nonpungent capsaicin analogues with potent antineoplastic activity. A major class of nonpungent capsaicin-like compounds belongs to the N-acyl-vanillylamide (N-AVAM) derivatives of capsaicin (hereafter referred as N-AVAM capsaicin analogues). This perspective discusses the isolation of N-AVAM capsaicin analogues from natural sources as well as their synthesis by chemical and enzymatic methods. The perspective describes the pharmacokinetic properties and anticancer activity of N-AVAM capsaicin analogues. The signaling pathways underlying the growth-inhibitory effects of N-AVAM capsaicin analogues have also been highlighted. It is hoped that the insights obtained in this perspective will facilitate the synthesis of a second generation of N-AVAM capsaicin analogues with improved stability and growth-suppressive activity in human cancer.

Topical Capsaicin for the Treatment of Neuropathic Pain.

BACKGROUND: Neuropathic pain (NP) is an egregious problem worldwide. Due to the side-effects of oral drugs, drugs delivered directly to the affected area of pain are preferred. OBJECTIVE: Capsaicin, a chemical compound isolated from chili peppers, is used as an analgesic in topical ointments and dermal patches to alleviate pain. Objective of the study is to review the application and functionality of topical capsaicin in treatment of neuropathic pain. DATA SOURCES: To systematically review capsaicin's functions on NP, we retrieved articles from the PubMed database published in the last ten years. STUDY ELIGIBILITY CRITERIA: The inclusion criteria were capsaicin and the use of capsaicin for the treatment of NP; on the other hand, articles were excluded according to the mentioned criteria such as abstracts, articles written in any language other than English, incomplete articles, and conference papers. PARTICIPANTS AND INTERVENTIONS: Out of 265 articles, 108 articles were selected after filtering through the inclusion and exclusion criteria. The data and knowledge currently existing for capsaicin treatment in NP are summarized. RESULTS: This review indicates that capsaicin effectively improves NP treatment without affecting the motor and large nerve fibres involved in sensory function. Transient receptor potential channel vanilloid type 1 (TRPV1) is the capsaicin receptor expressed in central and peripheral terminals of a sensitive primary nerve cell. Conclusions and implications of key findings: Topical capsaicin has a sensible safety profile and is effective in reducing NP. Therefore, studies over the last decade suggest that capsaicin might be a potential drug for NP treatment.

Intestinal absorption of black chokeberry cyanidin 3-glycosides is promoted by capsaicin and capsiate in a rat ligated small intestinal loop model.

Recent studies have shown that aronia (black chokeberry) and haskap fruits (contain anthocyanins) have beneficial health effects in animals and humans. However, some reports have shown that anthocyanin is poorly absorbed in the small intestine. In this study, we compared the intestinal absorption of aronia and haskap anthocyanins by using rats with a ligated small intestinal loop and cannulated portal vein. Our results clearly showed that the intestinal absorption of aronia anthocyanins was significantly lower than that of haskap anthocyanins, suggesting that the intestinal absorption of anthocyanins is influenced by the glycoside type (galactoside or glucoside). In addition, we also examined the effects of capsaicin and capsiate on intestinal anthocyanin absorption. The amount of aronia anthocyanins in portal blood was much higher when they were co-administered with capsaicin or capsiate. Our study is the first to show that the intestinal absorption of aronia anthocyanins is promoted by capsaicin and capsiate.

Capsaicin 8% Dermal Patch: A Review in Peripheral Neuropathic Pain.

The adhesive capsaicin dermal patch (Qutenza®) delivers a high concentration (8% w/w) of synthetic capsaicin, a highly selective agonist of transient receptor potential vanilloid-1 (TRPV-1), directly to the site of pain. The capsaicin 8% dermal patch is indicated in the EU for the treatment of peripheral neuropathic pain (PNP) in adults, either alone or in combination with other medicinal products for pain. In patients with painful diabetic peripheral neuropathy, a single 30-min application of the capsaicin 8% dermal patch provided 12 weeks of pain relief and improved sleep quality compared with placebo. Repeat treatment with the capsaicin 8% dermal patch plus standard of care over 52 weeks provided sustained pain relief, with no negative neurological effects compared with standard of care alone. The capsaicin 8% dermal patch was non-inferior to oral pregabalin in relieving pain in patients with non-diabetic PNP, with a faster onset of action and greater treatment satisfaction. A single 60-min application of the capsaicin 8% dermal patch provided rapid and sustained pain relief in patients with postherpetic neuralgia. Results in patients with HIV-associated neuropathy were equivocal, with a significant improvement in pain intensity observed in one trial, but not in the other. The capsaicin 8% dermal patch was generally well tolerated; transient application-site reactions were the most common adverse events. In conclusion, the capsaicin 8% dermal patch is a useful addition to the treatment options currently available for patients with PNP.

Effects of Phytochemical P-Glycoprotein Modulators on the Pharmacokinetics and Tissue Distribution of Doxorubicin in Mice.

Pungent spice constituents such as piperine, capsaicin and [6]-gingerol consumed via daily diet or traditional Chinese medicine, have been reported to possess various pharmacological activities. These dietary phytochemicals have also been reported to inhibit P-glycoprotein (P-gp) in vitro and act as an alternative to synthetic P-gp modulators. However, the in vivo effects on P-gp inhibition are currently unknown. This study aimed to test the hypothesis that phytochemical P-gp inhibitors, i.e., piperine, capsaicin and [6]-gingerol, modulate the in vivo tissue distribution of doxorubicin, a representative P-gp substrate. Mice were divided into four groups and each group was pretreated with intraperitoneal injections of control vehicle, piperine, capsaicin, or [6]-gingerol and doxorubicin (1 mg/kg) was administered via the penile vein. The concentrations of the phytochemicals and doxorubicin in the plasma and tissues were determined by LC-MS/MS. The overall plasma concentration-time profiles of doxorubicin were not significantly affected by piperine, capsaicin, or [6]-gingerol. In contrast, doxorubicin accumulation was observed in tissues pretreated with piperine or capsaicin. The tissue to plasma partition coefficients, Kp, for the liver and kidney were higher in the piperine-pretreated group, while the Kp for kidney, brain and liver were higher in the capsaicin-pretreated group. [6]-Gingerol did not affect doxorubicin tissue distribution. The data demonstrated that the phytochemicals modulated doxorubicin tissue distribution, which suggested their potential to induce food-drug interactions and act as a strategy for the delivery of P-gp substrate drugs to target tissues and tumors.

Cannabinoid hyperemesis syndrome: potential mechanisms for the benefit of capsaicin and hot water hydrotherapy in treatment.

INTRODUCTION: Cannabinoid hyperemesis syndrome is a clinical disorder that has become more prevalent with increasing use of cannabis and synthetic cannabinoids, and which is difficult to treat. Standard antiemetics commonly fail to alleviate the severe nausea and vomiting characteristic of the syndrome. Curiously, cannabinoid hyperemesis syndrome patients often report dramatic relief of symptoms with hot showers and baths, and topical capsaicin. OBJECTIVES: In this review, we detail the pharmacokinetics and pharmacodynamics of capsaicin and explore possible mechanisms for its beneficial effect, including activation of transient receptor potential vanilloid 1 and neurohumoral regulation. Putative mechanisms responsible for the benefit of hot water hydrotherapy are also investigated. METHODS: An extensive search of PubMed, OpenGrey, and Google Scholar from inception to April 2017 was performed to identify known and theoretical thermoregulatory mechanisms associated with the endocannabinoid system. The searches resulted in 2417 articles. These articles were screened for relevant mechanisms behind capsaicin and heat activation having potential antiemetic effects. References from the selected articles were also hand-searched. A total of 137 articles were considered relevant and included. Capsaicin: Topical capsaicin is primarily used for treatment of neuropathic pain, but it has also been used successfully in some 20 cases of cannabinoid hyperemesis syndrome. The pharmacokinetics and pharmacodynamics of capsaicin as a transient receptor potential vanilloid 1 agonist may explain this effect. Topical capsaicin has a longer half-life than oral administration, thus its potential duration of benefit is longer. Capsaicin and transient receptor potential vanilloid 1: Topical capsaicin binds and activates the transient receptor potential vanilloid 1 receptor, triggering influx of calcium and sodium, as well as release of inflammatory neuropeptides leading to transient burning, stinging, and itching. This elicits a novel type of desensitization analgesia. Transient receptor potential vanilloid 1 receptors also respond to noxious stimuli, such as heat (>43 °C), acids (pH <6), pain, change in osmolarity, and endovanilloids. The action of topical capsaicin may mimic the effect of heat-activation of transient receptor potential vanilloid 1. Endocannabinoid system and transient receptor potential vanilloid 1: Cannabinoid hyperemesis syndrome may result from a derangement in the endocannabinoid system secondary to chronic exogenous stimulation. The relief of cannabinoid hyperemesis syndrome symptoms from heat and use of transient receptor potential vanilloid 1 agonists suggests a complex interrelation between the endocannabinoid system and transient receptor potential vanilloid 1. Temperature regulation: Hot water hydrotherapy is a mainstay of self-treatment for cannabinoid hyperemesis syndrome patients. This may be explained by heat-induced transient receptor potential vanilloid 1 activation. "Sensocrine" antiemetic effects: Transient receptor potential vanilloid 1 activation by heat or capsaicin results in modulation of tachykinins, somatostatin, pituitary adenylate-cyclase activating polypeptide, and calcitonin gene-related peptide as well as histaminergic, cholinergic, and serotonergic transmission. These downstream effects represent further possible explanations for transient receptor potential vanilloid 1-associated antiemesis. CONCLUSIONS: These complex interactions between the endocannabinoid systems and transient receptor potential vanilloid 1, in the setting of cannabinoid receptor desensitization, may yield important clues into the pathophysiology and treatment of cannabinoid hyperemesis syndrome. This knowledge can provide clinicians caring for these patients with additional treatment options that may reduce length of stay, avoid unnecessary imaging and laboratory testing, and decrease the use of potentially harmful medications such as opioids.

CAPSAICIN: ITS BIOLOGICAL ACTIVITIES AND IN SILICO TARGET FISHING.

Capsicum annuum L. is a rich source of capsaicin, an alkaloid, which is a very pungent compound. Due to ever growing need of capsaicin, an extensive research on its efficient cultivation as well as chemical synthesis is underway. Owing to the pungent nature of capsaicin, its analogous molecules without pungent effect are being explored. The objective of this descriptive review is to comprehensively present the updates on the bioactivities of capsaicin. Additionally, the in silico target fishing approach has been used to identify the possible protein targets of capsaicin. This article will definitely provide future perspectives of research on capsaicin.

Capsaicin 8 % Patch: A Review in Peripheral Neuropathic Pain.

The capsaicin 8 % patch (QUTENZA®) is an adhesive patch containing a high concentration (8 % w/w) of synthetic capsaicin, a selective agonist of transient receptor potential vanilloid 1 channel. It is approved for treatment of peripheral neuropathic pain in adults either alone or in combination with other medicinal products for pain in the EU; it is only approved to treat postherpetic neuralgia (PHN) in the USA. In patients with painful diabetic peripheral neuropathy (PDPN), a single 30-min application of the capsaicin 8 % patch significantly improved pain relief and sleep quality compared with placebo in a 12-week double-blind trial. In a 52-week, randomized trial, up to seven consecutive 30-min treatments with the capsaicin 8 % patch (≤7 treatments each at least 8 weeks apart) plus standard of care therapy was associated with sustained pain relief and no negative neurological safety consequences compared with standard of care. In two randomized trials, a single 60-min application of the capsaicin 8 % patch reduced pain scores significantly more than a low-concentration (0.04 %) capsaicin control patch in patients with PHN. Capsaicin 8 % patch treatment was noninferior to pregabalin (optimized dosage) in a randomized trial in patients with nondiabetic peripheral neuropathic pain. Results in two trials in patients with HIV-AN were equivocal, with a significant improvement in pain intensity observed in one trial, but not in the other. The capsaicin 8 % patch was associated with expected, transient, capsaicin-related application-site adverse events such as erythema and pain.

Capsaicin-loaded vesicular systems designed for enhancing localized delivery for psoriasis therapy.

The aim of the current investigation is to evaluate the potential of capsaicin (CAP)-containing liposomes, niosomes and emulsomes in providing localized and controlled delivery, to improve the topical delivery of drug. CAP-bearing systems were prepared by the film hydration method and compared through various in vitro and in vivo parameters. The TEM photographs suggested that the carrier systems were spherical in shape and nanometric in size range. Skin retention studies of CAP from in vitro and in vivo experiments revealed significantly higher accumulation of drug in the case of the emul-gel formulation. Based on the results, we concluded that the emul-gel may be a potential approach for the topical delivery of CAP, for an effective therapy for psoriasis.

Infringement of the barriers of cancer via dietary phytoconstituents capsaicin through novel drug delivery system.

Cancer is the major cause of fatality and the number of new cases is increasing incessantly. Conventional therapies and existing anticancer agents cause serious side effects and expand the patient's lifespan by a few years. There is the need to exploit alternative anticancer agents and novel drug delivery system to deliver these agents to the tumor site for the prevention of cancer. Recently, biologically active compounds isolated from plants used for the management of cancer have been the heart of interest. Capsaicin is a major pungent agent present in the chili peppers that is heavily consumed in the world. Capsaicin has demonstrated effectiveness as an anticancer agent, but a restraining factor is its pungency, extremely low aqueous solubility, and poor oral bioavailability which impede its use as an anticancer agent. Many technologies have been developed and applied to conquer this drawback. We bring to light the benefits of this phytoconstituent for treating different types of cancer. We also discussed some of the delivery approaches that have already made an impact by either delivering a drug to target tissue or increasing its bioavailability by many folds.

In vitro and in vivo evaluation of capsaicin-loaded microemulsion for enhanced oral bioavailability.

BACKGROUND: Capsaicin, as a food additive, has attracted worldwide concern owing to its pungency and multiple pharmacological effects. However, poor water solubility and low bioavailability have limited its application. This study aims to develop a capsaicin-loaded microemulsion to enhance the oral bioavailability of the anti-neuropathic-pain component, capsaicin, which is poorly water soluble. RESULTS: In this study, the microemulsion consisting of Cremophor EL, ethanol, medium-chain triglycerides (oil phase) and water (external phase) was prepared and characterized (particle size, morphology, stability and encapsulation efficiency). The gastric mucosa irritation test of formulated capsaicin was performed in rats to evaluate its oral feasibility, followed by the pharmacokinetic study in vivo. Under these conditions, the encapsulated capsaicin revealed a faster capsaicin release in vitro coupled with a greater absorption in vivo when compared to the free capsaicin. The oral bioavailability of the formulated capsaicin-loaded microemulsions was 2.64-fold faster than that of free capsaicin. No significant irritation was observed on the mucosa from the pathological section of capsaicin-loaded microemulsion treated stomach. CONCLUSION: These results indicate that the developed microemulsion represents a safe and orally effective carrier for poorly soluble substances. The formulation could be used for clinical trials and expand the application of capsaicin.

Capsaicin delivery into the skin with lipidic nanoparticles for the treatment of psoriasis.

The study aims to explore the potential of solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) in improving the topical delivery of capsaicin (CAP) by in vitro and in vivo studies. The lipidic nanoparticles were prepared by solvent diffusion method and were characterized for average particle size, zeta potential and entrapment efficiency. TEM photomicrographs revealed that the particles were nanometric in size. Higher amount of CAP can be encapsulated in the NLCs (87.4 ± 3.28) as compared with SLNs (79.7 ± 2.93%). The cumulative amounts of CAP permeated through the skin and retained in the SC were higher in the case of NLCs as compared with plain drug solution and SLNs. SLNs and NLCs exhibited minimum to no irritation. All the results concluded that NLCs and SLNs have shown a good ability to increase drug accumulation in the various skin layers but NLCs may be a more potential carrier for topical delivery of CAP for an effective therapy of psoriasis.

QSAR and docking studies on capsazepine derivatives for immunomodulatory and anti-inflammatory activity.

Capsazepine, an antagonist of capsaicin, is discovered by the structure and activity relationship. In previous studies it has been found that capsazepine has potency for immunomodulation and anti-inflammatory activity and emerging as a favourable target in quest for efficacious and safe anti-inflammatory drug. Thus, a 2D quantitative structural activity relationship (QSAR) model against target tumor necrosis factor-α (TNF-α) was developed using multiple linear regression method (MLR) with good internal prediction (r2 = 0.8779) and external prediction (r2pred = 0.5865) using Discovery Studio v3.5 (Accelrys, USA). The predicted activity was further validated by in vitro experiment. Capsazepine was tested in lipopolysaccharide (LPS) induced inflammation in peritoneal mouse macrophages. Anti-inflammatory profile of capsazepine was assessed by its potency to inhibit the production of inflammatory mediator TNF-α. The in vitro experiment indicated that capsazepine is an efficient anti-inflammatory agent. Since, the developed QSAR model showed significant correlations between chemical structure and anti-inflammatory activity, it was successfully applied in the screening of forty-four virtual derivatives of capsazepine, which finally afforded six potent derivatives, CPZ-29, CPZ-30, CPZ-33, CPZ-34, CPZ-35 and CPZ-36. To gain more insights into the molecular mechanism of action of capsazepine and its derivatives, molecular docking and in silico absorption, distribution, metabolism, excretion and toxicity (ADMET) studies were performed. The results of QSAR, molecular docking, in silico ADMET screening and in vitro experimental studies provide guideline and mechanistic scope for the identification of more potent anti-inflammatory & immunomodulatory drug.

Preparation of a capsaicin-loaded nanoemulsion for improving skin penetration.

Capsaicin o/w nanoemulsions with enhanced skin permeation were successfully prepared by controlling the ratios of the surfactant mixtures, oleoresin capsicum as the oil phase, and aqueous phase. Oleoresin capsicum contains 22.67 mg/g of capsaicin, which is an active and oil-soluble ingredient. Nonionic surfactants, Tween 80 and Span 80, were used to optimize the weight ratio of surfactant mixtures (85.98:14.02) by calculating the hydrophile-lipophile balance (HLB) value. The optimal processing conditions for stable nanoemulsions were investigated by using a ternary phase diagram. The mean droplet size of nanoemulsions ranged from 20 to 62 nm. Skin permeation studies were performed using a Franz diffusion cell. The permeation profiles and confocal laser scanning microscopy (CLSM) images supported that capsaicin nanoemulsion could well permeate all skin layers from the stratum corneum to the dermis. The selected nanoemulsions showed great potential as transdermal delivery carriers for enhancing the permeation of core materials.

Consenso experto sobre el uso clínico de los tratamientos por vía tópica en el manejo del dolor neuropático periférico / No disponible

Objetivo: Proponer a partir del consenso de un panel de expertos de ambito estatal que integre la experiencia clinica y la evidencia disponible mas actual, recomendaciones sobre el uso clinico de los tratamientos por via topica para el manejo del dolor neuropatico periferico (DNP). Métodos: Se proponen, a partir de una revision bibliografica sobre las distintas opciones terapeuticas topicas en DNP, una serie de criterios profesionales y recomendaciones clinicas para la mejora del uso de dichos agentes topicos. Se empleo el metodo Delphi modificado en dos rondas para contrastar las opiniones de un panel nacional de 52 reconocidos expertos, seleccionados mediante una estrategia en “bola de nieve” de entre el colectivo de anestesiologos de unidades del dolor (94 %) y otros especialistas (neurologos y traumatologos). Se evaluaron 61 recomendaciones clinicas agrupadas en 6 areas tematicas: a) DNP: tratamiento topico versus sistemico (11 items); b) dolor neuropatico postquirurgico, postraumatico y munones dolorosos (12 items); c) neuralgia posherpetica, intercostal y del trigemino (9 items); d) DNP por atrapamiento (8 items); e) sindrome de dolor regional complejo (11 items); y f) neuropatia diabetica (ND) y otras polineuropatias (por VIH, alcohol, toxicidad, etc.) (10 items). Se empleo una escala ordinal de tipo Likert de 9 puntos (desacuerdo/ acuerdo) para evaluar cada recomendacion. Tras la primera ronda de encuesta, se facilito al panel informacion del resultado (resultados estadisticos y opiniones libres de los panelistas) y se solicito la reconsideracion del voto sobre los items no consensuados. Resultados: Tras la primera ronda del panel se logró consenso en 37 de las 61 cuestiones planteadas. Al final de la segunda ronda el acuerdo ascendió hasta 46 ítems (75 %). En general, se aprecia consenso entre los expertos sobre la conveniencia de introducir los tratamientos tópicos en primera línea de tratamiento del DNP y sobre su mejor aceptación por los pacientes frente a los sistémicos. Asimismo, fue criterio compartido que la combinación de estos fármacos tópicos con los tratamientos sistémicos es una opción a considerar en el manejo de varios tipos de DNP. También se alcanzó un alto grado de acuerdo en aceptar, desde un punto de vista fisiopatológico, la indicación del tratamiento con parche de capsaicina al 8 % para varios tipos de DNP. Conclusión: Los expertos en el manejo clínico del DNP muestran un elevado nivel de acuerdo profesional con diversas recomendaciones terapéuticas analizadas en el estudio. La difusión de tales recomendaciones puede ayudar a la mejora del manejo rutinario de fármacos tópicos para el dolor neuropático en nuestro sistema sanitario (AU)

Objective: To propose consensus from a panel of state level that integrates clinical experience and the most current evidence, recommendations on the clinical use of topical treatments for the management of peripheral neuropathic pain (PNP). Methods: We propose, based on a literature review on topical therapeutic options in PNP, a series of professional standards and clinical recommendations for improving the use of these topical agents. We used the modified Delphi method in two rounds to contrast the views of a national panel of 52 renowned experts, selected by a “snowball” strategy among the group of anesthesiologists pain units (94 %) and other specialists (neurologist and trauma). We evaluated 61 clinical recommendations grouped into 6 areas: a) PNP systemic versus topical treatment (11 items); b) postsurgical neuropathic pain, post-traumatic and painful stumps (12 items); c) post-herpetic neuralgia, intercostal and trigeminal (9 items); d) PNP entrapment (8 items); e) CRPS (11 items); and f) diabetic neuropathy (DN) and other polyneuropathy (HIV, alcohol, toxicity, etc.) (10 items). We used a Likert- type ordinal scale of 9 points (disagree/agree) to evaluate each recommendation. After the first round of the survey, information was provided requested to reconsider the vote on itemsnot agree. Results: After the first round the panel consensus was achieved in 37 of the 61 issues raised. At the end of the second round of the agreement amounted to 46 (75 %). In general, there was consensus among experts on whether to introduce topical treatment in first line treatment of PNP and its greater acceptance by patients compared with systemic. He was also a shared view consider in the management of various types of PNP. Also reached a high level of agreement to accept, from a physiological point of view, the indication for treatment with capsaicin patch 8 % for various types of PNP. Conclusions: Experts in the clinical management of PNP show a high level of professional agreement with various therapeutic recommendations for study. The dissemination of such recommendations can help improving the routine management of topical drugs for neuropathic pain in our health system (AU)

Capsaicina al 8 por ciento para controlar el dolor neuropático periférico: una estrategia basada en casos clínicos / No disponible

La reunión multidisciplinar organizada por Astellas tuvo lugar en Milán el 28 de agosto de 2012. Alrededor de 150 médicos invitados, especializados en el dolor, procedentes de toda Europa y con conocimientos o experiencia en el uso de los parches de capsaicina al 8 % para tratar el dolor neuropático (DN) periférico, asistieron a la reunión para escuchar la presentación de distintos casos clínicos tratados con el parche de capsaicina al 8%, por parte de un grupo de ponentes europeos expertos en la clínica del dolor. El objetivo de la reunión era compartir experiencia clínica real sobre el uso del parche de capsaicina al 8% para controlar el DN siguiendo un formato interactivo y dando a los asistentes la oportunidad de intercambiar experiencia práctica directa con el uso de este medicamento. La reunión estuvo presidida por el Dr. Arun Bhaskar del Reino Unido. Este inauguró la reunión dando la bienvenida a los delegados, presentando a los ponentes, resumiendo los objetivos de la reunión y realizando una demostración del ThoughtSort, el software que por grupos a través de un iPad, hizo posible que todos los participantes de la sesión pudiesen interactuar. Los detalles de los casos clínicos que se presentaron en la reunión y que se resumen en este artículo responden a las opiniones personales de los ponentes (AU)

The Astellas peer-to-peer meeting took place in Milan on the evening of Tuesday 28 August, 18:00-20:00. Approximately 150 invited pain physicians from across Europe, all with some knowledge or experience of using the high-dose capsaicin patch to treat peripheral neuropathic pain (NP), attended the meeting to hear an expert European faculty of practising physicians present different case studies involving treatment with high-dose capsaicin. The objective of the meeting was to share real-world experience in the use of high-dose capsaicin for the management of NP in an interactive format to provide delegates with the opportunity to liaise with physicians who have direct, handson experience of high-dose capsaicin. Interactivity was a key component of the meeting and iPad technology was utilised to encourage discussions between the faculty and the delegates. The ThoughtSort application enabled both the faculty to ask delegates questions related to their case studies and the delegates to ask the faculty questions throughout their presentations. The meeting was chaired by Dr Arun Bhaskar from the UK. He opened the meeting by welcoming the delegates, introducing the faculty, outlining the objectives of the meeting and performing a demonstration of ThoughtSort. The delegates had to work in groups to answer questions via ThoughtSort, using one iPad between four and five delegates. Details of the case studies that were presented at the meeting and summarised within this report are the personal opinions of the faculty members (AU)

Comparison of the effects of pelargonic acid vanillylamide and capsaicin on human vanilloid receptors.

Pelargonic acid vanillylamide is like capsaicin a natural capsaicinoid from chili peppers and commonly used in food additives to create a hot sensation, even in self-defense pepper sprays and as an alternative to capsaicin in medical products for topical treatment of pain. Although the chemical structures of both compounds are similar, preclinical data suggest that capsaicin is the more potent compound. We therefore performed voltage-clamp recordings using cells transfected with the human vanilloid receptor TRPV1 in order to assess the responses of pelargonic acid vanillylamide and capsaicin at the receptor level. We provide evidence that at the molecular target TRPV1, the concentration-response curves, kinetics of current activation, as well as inhibition by the competitive antagonist capsazepine were not significantly different between the two capsaicinoids. We suggest that the different effects of the two capsaicinoids observed in previous studies may rather be due to different physicochemical or pharmacokinetic properties than to different pharmacological profiles at the receptor level.

Uso del parche de capsaicina 8 por ciento para el tratamiento del dolor por infusión de treprostinil subcutáneo / No dispoinible

Introducción: la HP (hipertensión pulmonar) es una enfermedad poco prevalente (15 casos por 1 millón de habitantes), pero se trata de un proceso grave con una mortalidad muy elevada. El tratamiento se hace con treprostinil administrado por vía subcutánea. El principal efecto secundario que presenta es dolor e inflamación en el punto de infusión, obligando en muchos casos a la retirada del tratamiento. Presentamos un caso clínico de un paciente de 46 años diagnosticado de hipertensión pulmonar secundaria a VIH, que acude en tratamiento con treprostinil subcutáneo y que refirió intenso dolor en la zona de punción (zona abdominal periumbilical) los primeros días (4-5) de la infusión, con una intensidad muy severa (VAS 9-10) que le obligó a estar encamado. Planteamos la posibilidad de tratamiento con parche de capsaicina 8% (Qutenza®) de forma experimental, indicando al paciente su uso fuera de ficha técnica (off-label) y firmando el consentimiento informado. Se realiza tratamiento previo durante una hora con crema EMLA, según protocolo, se delimita la zona abdominal periumbilical (lugar de punción) y se administra parche durante una hora. Se observa posteriormente eritema en la zona de administración, sin más incidencia. Buena tolerancia del tratamiento y alta a domicilio. No existen publicaciones actualmente que hayan estudiado el uso de parche de capsaicina para tratar el dolor relacionado con la infusión de treprostinil s.c., por ello consideramos relevante la experiencia de este caso clínico. De este modo, creemos que, aunque pendiente de la validación por ensayos clínicos, el tratamiento con parches de capsaicina 8% (Qutenza®) podría ser una alternativa válida a tener en cuenta en el control analgésico de los pacientes en tratamiento con treprostinil s.c., logrando de este modo la adherencia a dicho tratamiento y que más pacientes puedan beneficiarse de teprsotinil para el tratamiento de la HP (AU)

Background: PH (Pulmonary Hypertension) is a low prevalence disease (15 cases per 1 million inhabitants), but is nevertheless a serious process with high mortality. Treprostinil is a new drug for the PH treatment, it is a prostacyclin with a half-life of 2-3 hours, which permits subcutaneous administration with rapid absorption and 100% bioavailability. The issue with treprostini is the high rate of drop-outs due to pain at the injection site. Aims: to reduce the rate of drop-outs due to pain at the injection site with the use of Treprostinil Methods: we searches in PubMed and Tripdatabase, fore terms, "capsaicin", "qutenza", "treprostinil", and "pulmonary hypertension", finding no related publication. The treatment with capsaicin 8% patch, was performed for one hour, according to the protocol, the peri-umbilical abdominal area (injection site) was delimited and the patch administered for one hour. Resul ts: erythema at the administration site was subsequently observed, albeit with no further incidents. Good treatment tolerance and discharge. In the control after 1 month, the patient reported changing the injection site to the treated area with a very striking reduction in pain (VAS 2-3) that enabled him to lead a normal life. The patient's satisfaction is very high, and he requires no coadjuvant or rescue treatment. At the 3-month control, the patient continues with the same level of analgesia Conclusions: capsaicin 8% patch could be a valid alternative to be considered in the analgesic control of patients on treatment with subcutaneous treprostinil (AU)

[Optimization of preparation process of floating sustained-release pellets of capsaicin based on nanometer CaCO3 by central composite design-response surface method].

OBJECTIVE: To prepare floating sustained-release pellets of capsaicin based on nanometer CaCO3. METHOD: The floating sustained-release pellets were prepared by the dropping method with sodium alginate as matrix. The effects of the concentration of sodium alginate, the ratio of capsaicin to sodium alginate and the ratio of nanometer CaCO3 to sodium alginate on pellets were detected in the single-factor test. On that basis, central composite design-response surface method were used to optimize the formula, with the floating capacity, drug-loading rate and in vitro drug release property of pellets as indicators. RESULT: In the optimal formula, CaCl2 accounted for 1.87%, the ratio of nanometer CaCO3 to sodium alginate was 2.16:1, and the ratio of capsaicin to sodium alginate was 2.36: 1, respectively. Capsaicin sustained-release pellets prepared under the conditions featured round granule, even particle size. It could float on artificial gastric fluid for over 15 hours, showing good sustained-release effect. Its accumulative drug-release percent of pellets in vitro at 12 h were 89.93%. CONCLUSION: The floating sustained-release pellets of capsaicin show good floating capacity and sustained-release effect after being optimized with central composite design-response surface method.

Topical capsaicin for pain management: therapeutic potential and mechanisms of action of the new high-concentration capsaicin 8% patch.

Topical capsaicin formulations are used for pain management. Safety and modest efficacy of low-concentration capsaicin formulations, which require repeated daily self-administration, are supported by meta-analyses of numerous studies. A high-concentration capsaicin 8% patch (Qutenza™) was recently approved in the EU and USA. A single 60-min application in patients with neuropathic pain produced effective pain relief for up to 12 weeks. Advantages of the high-concentration capsaicin patch include longer duration of effect, patient compliance, and low risk for systemic effects or drug-drug interactions. The mechanism of action of topical capsaicin has been ascribed to depletion of substance P. However, experimental and clinical studies show that depletion of substance P from nociceptors is only a correlate of capsaicin treatment and has little, if any, causative role in pain relief. Rather, topical capsaicin acts in the skin to attenuate cutaneous hypersensitivity and reduce pain by a process best described as 'defunctionalization' of nociceptor fibres. Defunctionalization is due to a number of effects that include temporary loss of membrane potential, inability to transport neurotrophic factors leading to altered phenotype, and reversible retraction of epidermal and dermal nerve fibre terminals. Peripheral neuropathic hypersensitivity is mediated by diverse mechanisms, including altered expression of the capsaicin receptor TRPV1 or other key ion channels in affected or intact adjacent peripheral nociceptive nerve fibres, aberrant re-innervation, and collateral sprouting, all of which are defunctionalized by topical capsaicin. Evidence suggests that the utility of topical capsaicin may extend beyond painful peripheral neuropathies.