Safety and Efficacy of Eletriptan in the Treatment of Acute Migraine

Migraine and Its Treatment from the Medicinal Chemistry Perspective

Migraine is a disease of neurovascular origin that affects the quality of life of more than one billion people and ranks sixth among the most common diseases in the world. Migraine is characterized by a moderate or severe recurrent and throbbing headache, accompanied by nausea, vomiting, and photo-phonophobia. It usually starts in adolescence and is twice as common in women as in men. It is classified as with or without aura and has chronic or acute treatment types according to the frequency of occurrence. In acute treatment, analgesics that relieve pain in the fastest way are preferred, while there are different options in chronic treatment. While non-specific methods were used in the treatment of migraine until the 1950s, triptans, ditans, and CGRP-receptor-dependent therapies (monoclonal antibodies and gepants) started to be used in the clinic more recently. In this Review, we focus on the synthesis, side effects, and pharmacological and pharmacokinetic properties of FDA-approved drugs used in acute and preventive-specific treatment of migraine.

Solvent-controlled regioselective C(5)-H/N(1)-H bond alkylations of indolines and C(6)-H bond alkylations of 1,2,3,4-tetrahydroquinolines with para-quinone methides

Solvent-promoted and -controlled regioselective bond alkylation reactions of para-quinone methides (p-QMs) with N-H free-indoline and 1,2,3,4-tetrahydroquinoline (THQ) under metal-free conditions have been developed. In the presence of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as the solvent, 1,6-addition alkylation reactions of p-QMs with NH-free indolines and THQs efficiently gave C5-alkylated indolines and C6-alkylated THQs. Using catalytic amounts of HFIP in DCM, the reaction of indolines and p-QMs resulted in the alkylation of indolines at the N1-position. HFIP plays two roles in the reactions: converting the indoline and THQ into bidentate nucleophiles and activating the p-QMs to achieve the 1,6-addition alkylation via hydrogen bond clusters. The indoline and THQ act as a C-nucleophile due to the H-bond clusters between HFIP and the nitrogen atom, whereas upon using catalytic amounts of HFIP, the compounds act as an N-nucleophile. All alkylation products were transformed into the corresponding indoles and quinolines via oxidation in the presence of diethyl azodicarboxylate (DEAD). Furthermore, the synthetic utilities have been showcased with both the removal of the tert-butyl groups from the C5-alkylated indole products and submission to their Suzuki coupling reactions.

A novel LC-MS method development and validation for the determination of phenyl vinyl sulfone in eletriptan hydrobromide

Background

The aim of the present method is to develop and validate a specific, sensitive, precise, and accurate liquid chromatography-mass spectrometry (LC-MS) method for the estimation of the phenyl vinyl sulfone in the eletriptan hydrobromide. The effective separation of the phenyl vinyl sulfone was achieved by the Symmetry C18 (50 × 4.6 mm, 3.5 μm) column and a mobile phase composition of 0.1%v/v ammonia buffer to methanol (5:95 v/v), using 0.45 ml/min flow rate and 20 μl of injection volume, with methanol used as diluent. The phenyl vinyl sulfone was monitored on atomic pressure chemical ionization mode mass spectrometer with positive polarity mode.

Results

The retention time of phenyl vinyl sulfone was found at 2.13 min. The limit of detection (LOD) and limit of quantification (LOQ) were observed at 1.43 ppm and 4.77 ppm concentration respectively; the linear range was found in the concentration ranges from 4.77 to 27.00 ppm with regression coefficient of 0.9990 and accuracy in the range of 97.50–102.10%. The percentage relative standard deviation (% RSD) for six replicates said to be injections were less than 10%.

Conclusion

The proposed method was validated successfully as per ICH guidelines. Hence, this is employed for the determination of phenyl vinyl sulfone in the eletriptan hydrobromide.

Stimuli-responsive In situ gelling system for nose-to-brain drug delivery

The diagnosis and treatment of neurological ailments always remain an utmost challenge for research fraternity due to the presence of BBB. The intranasal route appeared as an attractive and alternative route for brain targeting of therapeutics without the intrusion of BBB and GI exposure. This route directly and effectively delivers the therapeutics to different regions of the brain via olfactory and trigeminal nerve pathways. However, shorter drug retention time and mucociliary clearance curtail the efficiency of the intranasal route. The in situ mucoadhesive gel overthrow the limitations of direct nose-to-brain delivery by not only enhancing nasal residence time but also minimizing the mucociliary clearance and enzymatic degradation. This delivery system further improves the nasal absorption as well as bioavailability of drugs in the brain. The in situ mucoadhesive gel is a controlled and sustained release system that facilitates the absorption of various proteins, peptides and other larger lipophilic and hydrophilic moieties. Owing to multiple benefits, in situ gelling system has been widely explored to target the brain via nasal route. However, very few review works are reported which explains the application of in situ nasal gel for brain delivery of CNS acting moieties. Hence, in this piece of work, we have initially discussed the global statistics of neurological disorders reported by WHO and other reputed organizations, nasal anatomy, mechanism and challenges of nose-to-brain drug delivery. The work mainly focused on the use of different stimuli-responsive polymers, specifically thermoresponsive, pH-responsive, and ion triggered systems for the development of an effective and controlled dosage form, i.e., in situ nasal gel for brain targeting of bioactives. We have also highlighted the origin, structure, nature and phase transition behavior of the smart polymers found suitable for nasal administration, including poloxamer, chitosan, EHEC, xyloglucan, Carbopol, gellan gum and DGG along with their application in the treatment of neurological disorders. The article is aimed to gather all the information of the past 10 years related to the development and application of stimuli-responsive in situ nasal gel for brain drug delivery.

Assessment of the genotoxic potential of a migraine-specific drug by comet and cytokinesis-block micronucleus assays

Background: Eletriptan is a migraine-specific drug-containing the triptan group. In terms of drug safety, the present study aimed to investigate the genotoxic potential of eletriptan.Research design & methods: We conducted our study by using the cytokinesis-block micronucleus cytome (CBMN) assay, a comprehensive method for measuring micronucleus formation, and a sensitive method for detecting DNA-strand breaks. In the assay, cytokinesis-block proliferation index and the frequency of micronuclei were evaluated in lymphocytes treated with three different concentrations (1, 10 and 25 µg/ml) of eletriptan for 48 hours. In comet assays, DNA damage was evaluated in leucocytes treated with three different concentrations (1, 10 and 25 µg/ml) of eletriptan for an hour.Results: Eletriptan did not induce cytotoxicity nor any increased micronuclei frequencies. While the comet parameters % DNA in tail, tail moment, and the olive moment was found to be significantly increased at 10 and 25 µg/ml, the cytokinesis-block proliferation index values were not.Conclusion: These findings suggest that eletriptan is non-cytotoxic but potentially weakly genotoxic at higher concentrations (10 and 25 µg/ml).

Access to C5-Alkylated Indolines/Indoles via Michael-Type Friedel-Crafts Alkylation Using Aryl-Nitroolefins

A straightforward synthetic route toward C5-alkylated indolines/indoles has been developed. The strategy is composed of Zn(OTf)₂-catalyzed Friedel-Crafts alkylation of N-benzylindolines with nitroolefins, and a series of diverse indolines was first obtained in up to 99% yield. This reaction provides a direct and practical route to a variety of the C5-alkylated indolines which were also utilized for accessing corresponding indoles. Indoline derivatives with free NH groups could be obtained through an N-deprotection reaction. Moreover, the primary alkyl nitro groups in both indolines and indoles are amenable to further synthetic elaborations, thereby broadening the diversity of the products.

Eletriptan in the management of acute migraine: an update on the evidence for efficacy, safety, and consistent response

Migraine is a multifactorial, neurological and disabling disorder, also characterized by several autonomic symptoms. Triptans, selective serotonin 5-HT1B/1D agonists, are the first-line treatment option for moderate-to-severe headache attacks. In this paper, we review the recent data on eletriptan clinical efficacy, safety, and tolerability, and potential clinically relevant interactions with other drugs. Among triptans, eletriptan shows a consistent and significant clinical efficacy and a good tolerability profile in the treatment of migraine, especially for patients with cardiovascular risk factors without coronary artery disease. It shows the most favorable clinical response, together with sumatriptan injections, zolmitriptan and rizatriptan. Additionally, eletriptan shows the most complex pharmacokinetic/dynamic profile compared with the other triptans. It is metabolized primarily by the CYP3A4 hepatic enzyme and therefore the concomitant administration of CYP3A4-potent inhibitors should be carefully evaluated. A relatively low risk of serotonin syndrome is given by the co-administration with serotoninergic drugs. No clinically relevant interaction has been found with drugs used for migraine prophylactic treatment or other acute drugs, with the exception of ergot derivatives that should not be co-administered with eletriptan.

Thermoreversible nanoethosomal gel for the intranasal delivery of Eletriptan hydrobromide

The objective of the current study was to formulate and characterize thermoreversible gel of Eletriptan Hydrobromide for brain targeting via the intranasal route. Ethosomes were prepared by 3(2) factorial design with two independent variables (concentration of soya lecithin and ethanol) and two response variables [percent entrapment efficiency and vesicle size (nm)] using ethanol injection method. Formulated ethosomes were evaluated for preliminary microscopic examination followed by percent drug entrapment efficiency, vesicle size analysis, zeta potential, polydispersibility index and Transmission electron microscopy (TEM). TEM confirms spherical morphology of ethosomes, whereas Malvern zeta sizer confirms that the vesicle size was in the range of 191 ± 6.55-381.3 ± 61.0 nm. Ethosomes were incorporated in gel using poloxamer 407 and carbopol 934 as thermoreversible and mucoadhesive polymers, respectively. Ethosomal gels were evaluated for their pH, viscosity, mucoadhesive strength, in vitro drug release and ex vivo drug permeation through the sheep nasal mucosa. Mucoadhesive strength and pH was found to be 4400 ± 45 to 5500 ± 78.10 dynes/cm(2) and 6.0 ± 0.3 to 6.2 ± 0.1, respectively. In-vitro drug release from the optimized ethosomal gel formulation (G4) was found to be almost 100 % and ex vivo permeation of 4980 µg/ml with a permeability coefficient of 11.94 ± 0.04 × 10(-5) cm/s after 24 h. Histopathological study of the nasal mucosa confirmed non-toxic nature of ethosomal gels. Formulated EH loaded ethosomal thermoreversible gel could serve as the better alternative for the brain targeting via the intranasal route which in turn could subsequently improve its bioavailability.

Development and validation of a liquid chromatography-tandem mass spectrometric assay for quantitative analyses of triptans in hair

Triptans are specific drugs widely used for acute treatment of migraine, being selective 5HT1B/1D receptor agonists. A proper assumption of triptans is very important for an effective treatment; nevertheless patients often underuse, misuse, overuse or use triptans inconsistently, i.e., not following the prescribed therapy. Drug analysis in hair can represent a powerful tool for monitoring the compliance of the patient to the therapy, since it can greatly increase the time-window of detection compared to analyses in biological fluids, such as plasma or urine. In the present study, a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method has been developed and validated for the quantitative analysis in human hair of five triptans commonly prescribed in Italy: almotriptan (AL), eletriptan (EP), rizatriptan (RIZ), sumatriptan (SUM) and zolmitriptan (ZP). Hair samples were decontaminated and incubated overnight in diluted hydrochloric acid; the extracts were purified by mixed-mode SPE cartridges and analyzed by LC-MS/MS under gradient elution in positive multiple reaction monitoring (MRM) mode. The procedure was fully validated in terms of selectivity, linearity, limit of detection (LOD) and lower limit of quantitation (LLOQ), accuracy, precision, carry-over, recovery, matrix effect and dilution integrity. The method was linear in the range 10-1000pg/mg hair, with R(2) values of at least 0.990; the validated LLOQ values were in the range 5-7pg/mg hair. The method offered satisfactory precision (RSD <10%), accuracy (90-110%) and recovery (>85%) values. The validated procedure was applied on 147 authentic hair samples from subjects being treated in the Headache Centre of Modena University Hospital in order to verify the possibility of monitoring the corresponding hair levels for the taken triptans.

Acute treatment of migraine

Acute treatment of migraine has benefited first from major advances in pharmacological science followed in short order, sometimes preceded, by an improved understanding of pathogenesis, especially of headache. This chapter reviews the mechanisms of migraine that provide an understanding of the pharmacology and therapeutic targets for acute migraine medications. General clinical approaches to acute therapy are reviewed, and indices of acceptable acute therapeutic outcomes are discussed. Currently the serotonin (5-HT) 1B/1D agonist group of drugs, triptans, forms the mainstay of acute therapeutic regimens. Other approaches to acute treatment such as simple analgesics, non-steroidal anti-inflammatory drugs (NSAIDs), ergots, and combination medications are reviewed. Finally, the newest acute treatments that are currently exploratory or under clinical investigation are discussed.

Vasoactive peptides in cardiovascular (patho)physiology

Numerous vasoactive agents play an important physiological role in regulating vascular tone, reactivity and structure. In pathological conditions, alterations in the regulation of vasoactive peptides result in endothelial dysfunction, vascular remodeling and vascular inflammation, which are important processes underlying vascular damage in cardiovascular disease. Among the many vasoactive agents implicated in vascular (patho)biology, angiotensin II (Ang II), endothelin (ET), serotonin and natriuretic peptides appear to be particularly important because of their many pleiotropic actions and because they have been identified as potential therapeutic targets in cardiovascular disease. Ang II, ET-1, serotonin and natriuretic peptides mediate effects via specific receptors, which belong to the group of G-protein-coupled receptors. ET, serotonin and Ang II are primarily vasoconstrictors with growth-promoting actions, whereas natriuretic peptides, specifically atrial, brain and C-type natriuretic peptides, are vasodilators with natriuretic effects. Inhibition of vasoconstrictor actions with drugs that block peptide receptors, compounds that inhibit enzymes that generate vasoactive peptides or agents that increase levels of natriuretic peptides are potentially valuable therapeutic tools in the management of cardiovascular diseases. This review focuses on ET, natriuretic peptides and serotonin. The properties and distribution of these vasoactive agents and their receptors, mechanisms of action and implications in cardiovascular (patho)physiology will be discussed.

Pharmacokinetics and interactions of headache medications, part II: prophylactic treatments

The present part II review highlights pharmacokinetic drug-drug interactions (excluding those of minor severity) of medications used in prophylactic treatment of the main primary headaches (migraine, tension-type and cluster headache). The principles of pharmacokinetics and metabolism, and the interactions of medications for acute treatment are examined in part I. The overall goal of this series of two reviews is to increase the awareness of physicians, primary care providers and specialists regarding pharmacokinetic drug-drug interactions (DDIs) of headache medications. The aim of prophylactic treatment is to reduce the frequency of headache attacks using beta-blockers, calcium-channel blockers, antidepressants, antiepileptics, lithium, serotonin antagonists, corticosteroids and muscle relaxants, which must be taken daily for long periods. During treatment the patient often continues to take symptomatic drugs for the attack, and may need other medications for associated or new-onset illnesses. DDIs can, therefore, occur. As a whole, DDIs of clinical relevance concerning prophylactic drugs are a limited number. Their effects can be prevented by starting the treatment with low dosages, which should be gradually increased depending on response and side effects, while frequently monitoring the patient and plasma levels of other possible coadministered drugs with a narrow therapeutic range. Most headache medications are substrates of CYP2D6 (e.g., beta-blockers, antidepressants) or CYP3A4 (e.g., calcium-channel blockers, selective serotonin re-uptake inhibitors, corticosteroids). The inducers and, especially, the inhibitors of these isoenzymes should be carefully coadministered.