The triptan formulations: a critical evaluation

Delivery of Dihydroergotamine Mesylate to the Upper Nasal Space for the Acute Treatment of Migraine: Technology in Action

Oral tablets account for the majority of medications used to acutely treat migraine, but relief can be limited by their rates of dissolution and absorption. The nose is an attractive alternative route of drug delivery since it provides patient convenience of at-home use, gastrointestinal (GI) avoidance, and rapid absorption of drugs into systemic circulation because of its large surface area. However, the site of drug deposition within the nasal cavity should be considered since it can influence drug absorption. Traditional nasal devices have been shown to target drug delivery to the lower nasal space where epithelium is not best-suited for drug absorption and where there is an increased likelihood of drug clearance due to nasal drip, swallowing, or mucociliary clearance, potentially resulting in variable absorption and suboptimal efficacy. Alternatively, the upper nasal space (UNS) offers a permeable, richly vascularized epithelium with a decreased likelihood of drug loss or clearance due to the anatomy of this area. Traditional nasal pumps deposit <5% of active drug into the UNS because of the nasal cavity's complex architecture. A new technology, Precision Olfactory Delivery (POD^®), is a handheld, manually actuated, propellant-powered, administration device that delivers drug specifically to the UNS. A dihydroergotamine (DHE) mesylate product, INP104, utilizes POD technology to deliver drug to the UNS for the acute treatment of migraine. Results from clinical studies of INP104 demonstrate a favorable pharmacokinetic profile, consistent and predictable dosing, rapid systemic levels known to be effective (similar to other DHE mesylate clinical programs), safety and tolerability on the upper nasal mucosa, and high patient acceptance. POD technology may have the potential to overcome the limitations of traditional nasal delivery systems, while utilizing the nasal delivery benefits of GI tract avoidance, rapid onset, patient convenience, and ease of use.

Sex Differences in Response to Triptans: A Systematic Review and Meta-analysis

OBJECTIVE

To examine the effect of sex on clinical response to triptans in migraine and to determine whether these differences are related to pharmacokinetics of triptans in men and women, we performed a systematic review and meta-analysis.

METHODS

We searched clinical trials distinguishing clinical response to or pharmacokinetic parameters of triptans between sexes in PubMed, MEDLINE, Cochrane Library, Embase, and Web of Science up to Dec 12, 2019. Analysis was based on data extracted from published reports. Male-to-female pooled risk ratios (RR) were calculated for clinical outcomes and pooled ratio of means (RoM) for pharmacokinetic outcomes using random-effects models.

RESULTS

Of 1,188 publications on clinical trials with triptans, 244 were identified with sex-related search terms. Only 19 publications presented sex-specific results, comprising n = 2,280 men and n = 13,899 women. No sex differences were revealed for 2-hour headache and pain-free responses, but men had a lower risk for headache recurrence (male-to-female RR 0.64, 95% confidence interval [CI]: 0.55-0.76, Q = 0.81) and adverse events (RR 0.82, 95% CI: 0.72-0.93, Q = 4.93). Men had lower drug exposure with lower area under the curve (RoM 0.69, 95% CI: 0.60-0.81, Q = 18.06) and peak drug concentration (RoM 0.72, 95% CI: 0.64-0.82, Q = 8.24) than women.

CONCLUSIONS

Remarkably few publications about sex differences in triptan response are available. The limited number of eligible studies show sex differences in adverse event frequency, which may be partly because of drug exposure differences. This higher drug exposure in women is not reflected in different response rates. Despite higher exposure, women have higher headache recurrence rates possibly because of longer attack duration related to sex hormonal changes.

Nose-to-brain delivery of sumatriptan-loaded nanostructured lipid carriers: preparation, optimization, characterization and pharmacokinetic evaluation

OBJECTIVES

Migraine is a neurological disorder with unilateral pulsatile headache which can affect the functions of sufferers. Migraineurs experience some undesirable symptoms such as pain, nausea, vomiting and in some cases auras which make the oral delivery non-selective. The lipid nanoparticles are considered as good carriers for nose-to-brain drug delivery. The present study aimed to formulate and evaluate a sumatriptan-loaded nanostructured lipid carrier (NLC).

METHODS

A drug-loaded NLC was optimized using D-optimal design of experiment and then the characterization of the formulated NLC including particle size, zeta potential, electron microscopy, thermal analysis, drug loading efficiency and release kinetics were carried out. Pharmacokinetic evaluations were also performed during an in-vivo study on Sprague-Dawley rats and neuropharmacokinetic parameters such as drug targeting efficiency (DTE) and direct transport percentage (DTP) were calculated.

KEY FINDINGS

The optimization of experiments led to nanoparticles with 101 nm mean diameter and polydispersity index (PDI) of 0.27. The drug entrapment efficiency (EE) for optimized nanoparticle was found to be 91.00%. DTE and DTP of intranasal-administered NLC were calculated 258.02% and 61.23%, respectively.

CONCLUSIONS

Neuropharmacokinetic evaluation of intranasal NLC dispersion represents a suitable brain delivery system. The DTP of NLC formulation suggests the desirable entrance of sumatriptan into the brain.

Preparation and Optimization of Fast-Disintegrating Tablet Containing Naratriptan Hydrochloride Using D-Optimal Mixture Design

Optimization of a lyophilized fast-disintegrating tablet (LFDT) formulation containing naratriptan hydrochloride, an antimigraine drug, was the foremost objective of the study, aiming in achieving fast headache pain relief. The Design-Expert® v10 software was used to generate formulations using D-optimal mixture design with four components: gelatin (X₁), hydrolyzed gelatin (X₂), glycine (X₃), and mannitol (X₄) of total solid material (TSM) w/w. The effect of the relative proportion of each component was determined on friability (Y₁), hardness (Y₂), and in vitro disintegration time (Y₃), which was then applied for formulation optimization. In addition, their effect on tablet porosity was determined via scanning electron microscopy (SEM). Drug-excipient interaction was evaluated using differential scanning calorimetry (DSC). A comparative dissolution study against the conventional tablets was studied. Accelerated stability study was carried out in (Al/Al) and (Al/PVC) blister packs. An in vivo pharmacokinetic study was carried out to compare the optimized formulation and the conventional tablets. The optimized formulation's responses were 0.30%, 3.4 kg, and 6.12 s for Y₁, Y₂, and Y₃, respectively. No drug-excipient interaction was specified via DSC. The optimized formulation exhibited porous structure as determined via SEM. Dissolution study demonstrated complete dissolution within 1.5 min. Study indicated stability for 78 months in (Al/Al) blister packs. In vivo pharmacokinetic study demonstrated that C_max, AUC_last, and AUC_inf were significantly higher for the developed formulation. As well, the T_max was 1 h earlier than that of convenient tablet. An LFDT would achieve a faster onset of action for naratriptan compared to other formulations.

Migraine Treatment: Current Acute Medications and Their Potential Mechanisms of Action

Migraine is a common and disabling primary headache disorder with a significant socioeconomic burden. The management of migraine is multifaceted and is generally dichotomized into acute and preventive strategies, with several treatment modalities. The aims of acute pharmacological treatment are to rapidly restore function with minimal recurrence, with the avoidance of side effects. The choice of pharmacological treatment is individualized, and is based on the consideration of the characteristics of the migraine attack, the patient's concomitant medical problems, and treatment preferences. Notwithstanding, a good understanding of the pharmacodynamic and pharmacokinetic properties of the various drug options is essential to guide therapy. The current approach and concepts relevant to the acute pharmacological treatment of migraine will be explored in this review.

Brain targeting efficiency of antimigrain drug loaded mucoadhesive intranasal nanoemulsion

Zolmitriptan (ZT) is a well-tolerated drug in migraine treatment suffering from low bioavailability due to low amount of the drug that reaches the brain after oral and nasal delivery. Development of new nasal mucoadhesive nanoemulsion formulation for zolmitriptan may success in delivering the drug directly from the nose to the brain to achieve rapid onset of action and high drug concentration in the brain which is required for treatment of acute migraine. ZT mucoadhesive nanoemulsion were prepared and characterized for drug content, zeta potential, particle size, morphology, residence time and permeation through the nasal mucosa. The selected formula was tested in-vivo in mice for its pharmacokinetics in comparison with intravenous and nasal solution of zolmitriptan. Results showed that addition of chitosan as mucoadhesive agent in 0.3% concentration to the nanoemulsion enhanced its residence time and zetapotential with no significant effect on the globule size. All tested formulations showed higher permeability coefficients than the zolmitriptan solution through the nasal mucosa. In-vivo studies showed that the mucoadhesive nanoemulsion formulation of zolmitriptan has higher AUC_0-8 and shorter T_max in the brain than the intravenous or the nasal solution. This was related to the small globule size and higher permeability of the formulation.

Effect of Microneedle Type on Transdermal Permeation of Rizatriptan

The present study was aimed to investigate the effect of salient microneedle (MN) geometry parameters like length, density, shape and type on transdermal permeation of rizatriptan (RIZ). Studies were carried out using two types of MN devices viz. AdminPatch® arrays (ADM) (0.6, 0.9, 1.2 and 1.5 mm lengths) and laboratory-fabricated polymeric MNs (PMs) of 0.6 mm length. In the case of the PMs, arrays were applied three times at different places within a 1.77-cm² skin area (PM-3) to maintain the MN density closer to 0.6 mm ADM. Histological studies revealed that PM, owing to their geometry/design, formed wider and deeper microconduits when compared to ADM of similar length. Approximately 4.9- and 4.2-fold increases in the RIZ steady-state flux values were observed with 1.5 mm ADM and PM-3 applications when compared to the passive studies. A good correlation between different dimensionless parameters like the amount of RIZ permeated (C _t /C _s), thickness (h/L) and surface area (S _a/L ²) of the skin was observed with scaling analyses. Numerical simulations provided further information regarding the distribution of RIZ in MN-treated skin after application of different MNs. Overall, the study suggests that MN application enhances the RIZ transdermal permeation and the geometrical parameters of MNs play an important role in the degree enhancement.

Microneedle-assisted transdermal delivery of Zolmitriptan: effect of microneedle geometry, in vitro permeation experiments, scaling analyses and numerical simulations

OBJECTIVE

The present study was aimed to investigate the effect of salient microneedle (MN) geometry parameters like length, density, shape and type on transdermal permeation enhancement of Zolmitriptan (ZMT).

METHODS

Two types of MN devices viz. AdminPatch^® arrays (ADM) (0.6, 0.9, 1.2 and 1.5 mm lengths) and laboratory fabricated polymeric MNs (PM) of 0.6 mm length were employed. In the case of PMs, arrays were applied thrice at different places within a 1.77 cm² skin area (PM-3) to maintain the MN density closer to 0.6 mm ADM. Scaling analyses was done using dimensionless parameters like concentration of ZMT (C_t/C_s), thickness (h/L) and surface area of the skin (Sa/L²).

RESULTS

Micro-injection molding technique was employed to fabricate PM. Histological studies revealed that the PM, owing to their geometry/design, formed wider and deeper microconduits when compared to ADM of similar length. Approximately 3.17- and 3.65-fold increase in ZMT flux values were observed with 1.5 mm ADM and PM-3 applications when compared to the passive studies. Good correlations were observed between different dimensionless parameters with scaling analyses. Numerical simulations, using MATLAB and COMSOL software, based on experimental data and histological images provided information regarding the ZMT skin distribution after MN application.

DISCUSSION

Both from experimental studies and simulations, it was inferred that PM were more effective in enhancing the transdermal delivery of ZMT when compared to ADM.

CONCLUSIONS

The study suggests that MN application enhances the ZMT transdermal permeation and the geometrical parameters of MNs play an important role in the degree of such enhancement.

Infrequent or Non-Response to Oral Sumatriptan does not Predict Response to Other Triptans—Review of Four Trials

A migraineur can claim to be an infrequent responder (‘non-responder’) to an oral triptan independent of which triptan he or she is presently using. Four trials of an alternative triptan (zolmitriptan/rizatriptan; eletriptan; naratriptan; almotriptan) in patients with a history of infrequent response to oral sumatriptan were compared and contrasted in terms of study design, patient characteristics, and efficacy and tolerability of the triptan under investigation. Unfortunately, none of the reported studies used an appropriate parallel design, which would have had the non-responding triptan (oral sumatriptan) in one arm and without encapsulation. While the four trials differed in terms of study design (open-label vs. placebo-controlled), definition of sumatriptan ‘non-responder’ (retrospective vs. prospective) and pain intensity at baseline (30% severe to 70% severe), all four demonstrated that lack of response to sumatriptan did not predict lack of response to an alternative triptan. Changing triptans resulted in 2-h pain-relief rates of 25–81% in patients with a history of poor response to sumatriptan. It can be concluded that migraine patients who respond infrequently to sumatriptan should be switched to a different triptan, as lack of response to one triptan does not predict likelihood of responsiveness to another. A review of the available evidence suggests that almotriptan may be one of the most appropriate choices for an alternative triptan.

Sumatriptan (all routes of administration) for acute migraine attacks in adults - overview of Cochrane reviews

BACKGROUND

Migraine is a highly disabling condition for the individual and also has wide-reaching implications for society, healthcare services, and the economy. Sumatriptan is an abortive medication for migraine attacks, belonging to the triptan family. It is available for administration by four different routes: oral, subcutaneous, intranasal, and rectal.

OBJECTIVES

To summarise evidence from four Cochrane intervention reviews on the efficacy and tolerability of sumatriptan in the treatment of acute migraine attacks in adults by four routes of administration (oral, subcutaneous, intranasal, and rectal) compared with both placebo and active comparators.

METHODS

The included reviews were written by the authors of this overview; no additional searching was carried out. All included reviews were conducted according to a standard protocol and reported a standard set of outcomes. From each individual review we extracted results for pain relief at different levels, and adverse events. No additional statistical comparison was undertaken as part of the overview. We focused on the most important findings for doses and routes licensed in North America or Europe (oral 25 mg, 50 mg, 100 mg; subcutaneous 4 mg, 6 mg; intranasal 5 mg, 10 mg, 20 mg; rectal 25 mg).

MAIN RESULTS

Included reviews provided data for 18 different dose and route of administration combinations in 52,236 participants. Data for the primary outcomes sought were generally well reported, and involved adequate numbers of participants to give confidence in the results, except for the rectal route of administration, where numbers were low.Subcutaneous administration was the most effective, with pain reduced from moderate or severe to none by two hours in almost 6 in 10 people (59%) taking 6 mg sumatriptan, compared with approximately 1 in 7 (15%) taking placebo; the number needed to treat (NNT) was 2.3 (95% confidence interval 2.1 to 2.4) with 2522 participants in the analysis. The most commonly used doses of oral, rectal, and intranasal sumatriptan also provided clinically useful pain relief, with the oral 50 mg dose providing complete relief of pain in almost 3 in 10 people (28%) compared with about 1 in 10 (11%) after placebo (NNT 6.1 (5.5 to 6.9) in 6447 participants). Subcutaneous administration provided more rapid pain relief than the other routes. Taking medication early, when pain was mild, was more effective than waiting until the pain was moderate or severe.The most effective dose of sumatriptan for each route of administration for the outcome of headache relief (pain reduced from moderate or severe to none or mild) at two hours was oral 100 mg (NNT 3.5 (3.2 to 3.7) in 7811 participants), subcutaneous 6 mg (NNT 2.1 (2.0 to 2.2) in 2738 participants), intranasal 20 mg (NNT 3.5 (3.1 to 4.1) in 2020 participants), and rectal 25 mg (NNT 2.4 (1.9 to 3.4) in 240 participants).Adverse events were generally of mild or moderate severity, of short duration, and more common with subcutaneously administered sumatriptan and higher doses of oral and intranasal sumatriptan than with other dose and route combinations.

AUTHORS' CONCLUSIONS

Sumatriptan is an effective abortive treatment for acute migraine attacks, but is associated with increased adverse events relative to placebo. The route of administration influences efficacy, particularly within the first hour after administration. Subcutaneous sumatriptan shows the greatest efficacy in terms of pain relief, but at the expense of relatively high levels of adverse events, and with a high financial cost compared with other routes. Information about the relative efficacy of the different routes of administration for different outcomes should help to inform decisions about the suitability of sumatriptan as a migraine treatment, as well as about the most appropriate way to administer the treatment for individual patients.

Insights into direct nose to brain delivery: current status and future perspective

Now a day's intranasal (i.n) drug delivery is emerging as a reliable method to bypass the blood-brain barrier (BBB) and deliver a wide range of therapeutic agents including both small and large molecules, growth factors, viral vectors and even stem cells to the brain and has shown therapeutic effects in both animals and humans. This route involves the olfactory or trigeminal nerve systems which initiate in the brain and terminate in the nasal cavity at the olfactory neuroepithelium or respiratory epithelium. They are the only externally exposed portions of the central nervous system (CNS) and therefore represent the most direct method of noninvasive entry into the brain. This approach has been primarily used to explore therapeutic avenues for neurological diseases. The potential for treatment possibilities with olfactory transfer of drugs will increase as more effective formulations and delivery devices are developed. Recently, the apomorphine hydrochloride dry powders have been developed for i.n. delivery (Apomorphine nasal, Lyonase technology, Britannia Pharmaceuticals, Surrey, UK). The results of clinical trial Phase III suggested that the prepared formulation had clinical effect equivalent to subcutaneously administered apomorphine. In coming years, intranasal delivery of drugs will demand more complex and automated delivery devices to ensure accurate and repeatable dosing. Thus, new efforts are needed to make this noninvasive route of delivery more efficient and popular, and it is also predicted that in future a range of intranasal products will be used in diagnosis as well as treatment of CNS diseases. This review will embark the existing evidence of nose-to-brain transport. It also provides insights into the most relevant pre-clinical studies of direct nose-brain delivery and delivery devices which will provide relative success of intranasal delivery system. We have, herein, outlined the relevant aspects of CNS drugs given intranasally to direct the brain in treating CNS disorders like Alzheimer's disease, depression, migraine, schizophrenia, etc.

A review of the use of frovatriptan in the treatment of menstrually related migraine

Menstrual migraine (MM) is a highly prevalent condition associated with considerable disability. Migraine attacks occur exclusively around the menstrual period in approximately 10% of women with migraine, that is, pure menstrual migraine, while at least 50% of them also experience migraine at other times of the month, that is, menstrually related migraine (MRM). The therapeutic approach to patients with MRM is based on treatment of the attack, or prophylactic strategies. Triptans are recommended as first-line treatments for moderate to severe migraine attacks, including MM. Frovatriptan is one of the newest triptans. Its high affinity for 5-HT1B/1D receptors and long half-life contribute to its distinctive clinical effect, characterized by a more sustained and prolonged effect than other triptans. Indeed, frovatriptan proved to be effective in treating the acute attack, but was particularly effective in the short-term preventive therapy of MM. In addition, frovatriptan is one of the safest triptans, with the lowest risk of treatment-emergent adverse events. Following extensive evidence from randomized pharmacological trials, frovatriptan has now gained a grade A recommendation from the guidelines for short-term prophylaxis of MM. Recent post-hoc analyses of direct comparative trials also suggest that frovatriptan might have an important role in the acute treatment of MRM. In these studies, frovatriptan showed pain relief and pain-free rates similar to those of zolmitriptan, rizatriptan, and almotriptan, but with significantly lower recurrence rates. More well-designed, randomized, prospective studies, specifically enrolling women with MM, will be needed in the near future to confirm the efficacy of frovatriptan in this migraine subtype.

Influence of polymeric microcarriers on the in vivo intranasal uptake of an anti-migraine drug for brain targeting

The objective of this study was to investigate the effect of polymeric microcarriers on the in vivo intranasal uptake of an anti-migraine drug for brain targeting. Mucoadhesive powder formulations consisted of antimigraine drug, zolmitriptan, and chitosans (various molecular weights and types) or hydroxypropyl methylcellulose (HPMC). Their suitability for nasal administration was evaluated by in vitro and ex vivo mucoadhesion and permeation tests. The formulations based on chitosan glutamate (CG) or HPMC were tested in vivo because they showed good mucoadhesive properties and altered the permeation rate of the drug. The in vivo results from intravenous infusion and nasal aqueous suspension of the drug or nasal particulate powders were compared. The plasmatic AUC values obtained within 8h following intravenous administration appeared about three times higher than those obtained by nasal administration, independent of the formulations. Zolmitriptan concentrations in the cerebrospinal fluid obtained from nasal and intravenous administrations were, respectively, 30 and 90 times lower than the concentrations of the drug in the blood. Thus, nasal administration potentiated the central zolmitriptan activity, allowing a reduction in the drug peripheral levels, with respect to the intravenous administration. Among nasally administered formulations, CG microparticles showed the highest efficacy in promoting the central uptake of zolmitriptan within 1h.

Pharmacokinetic evaluation of zolmitriptan for the treatment of migraines

INTRODUCTION

Migraine is a multifactorial neurovascular disorder characterized by recurrent episodes of disabling pain attacks, accompanied with gastrointestinal, neurological systems dysfunction. The pharmacologic treatment of migraine is classically divided in the management of the acute attack and preventive strategies. Acute treatments consist of triptan, ergot, opioid, antiemetic and NSAIDs.

AREAS COVERED

This article discusses pharmacodynamics and pharmacokinetics of zolmitriptan . The data were obtained by searching the following keywords in MEDLINE: zolmitriptan, pharmacokinetics, pharmacodynamics, triptans, migraine, menstrual-related migraine, cluster headache, relatively to the period 1989 - 2012.

EXPERT OPINION

Zolmitriptan has been considered effective treatment in the acute phase of migraine, menstrual-related migraine and cluster headache attacks. Pharmacokinetic parameters may vary as a consequence of gender differences, inter- and intra-subjects variability and delivery system. Zolmitriptan was developed with the aim of obtaining a lipophilic compound in order to be more rapidly absorbed and centrally active. Pharmacologically, pharmacokinetic parameters are responsible for its wide efficacy and the limited adverse effect profile.

Overview of migraine treatment

SUMMARY Migraine is ranked as the 19th top cause of disability worldwide by WHO. Despite advancements in migraine-specific acute treatment, only a minority of patients utilize these medications. Specific pharmacologic treatments consist of the ergot alkaloids and triptans (serotonin 5-HT1B/1D receptor agonists). Both classes are regarded as relatively safe and effective; however, there is a greater concern for vasoconstrictive effects with the ergots, which limits their use. Triptans transformed migraine therapy, setting in motion revolutionary research that heightened our understanding of migraine mechanisms. However, one in three migraineurs may be triptan nonresponders and there is a group of migraine patients that remains ‘refractory’ to conventional pharmacologic migraine therapy. This article discusses the approach to migraine management, reviews currently available acute and preventive pharmacologic and nonpharmacologic treatment options for migraine headache, as well as briefly focuses on novel and upcoming medicines presently under investigation.

Needle-free subcutaneous sumatriptan for triptan users requiring a change in migraine therapy: efficacy and impact on patient-rated functionality, satisfaction, and confidence

OBJECTIVE

To evaluate efficacy of, satisfaction with, and confidence in SDP (SUMAVEL DosePro *) among triptan users requiring a change in therapy. SDP is a needle-free, subcutaneous sumatriptan product that confers relief as early as 10 minutes postdose.

RESEARCH DESIGN AND METHODS

In an open-label study, SDP was administered for ≤4 migraine attacks over ≤60 days by migraineurs currently treated with triptans (any form/dosage). In the 90 patients with baseline Migraine-ACT scores ≤2 (indicating the need for a change in therapy), efficacy data were collected from patient diaries, and satisfaction was measured with the revised Patient Perception of Migraine Questionnaire (PPMQ-R).

CLINICAL TRIAL REGISTRATION NUMBER

NCT01016834 on clinicaltrials.gov.

RESULTS

Across all attacks, the rates of pain relief were 30.7%, 66.4%, 80.1%, 81.6%, and 77.6% at 0.25, 0.5, 1, 2, and 24 hours postdose, respectively. Corresponding results for pain-free response were 0.7%, 14.8%, 35.0%, 48.0, and 65.7%. Sustained 24-hour pain relief was observed in 61.0% of attacks. PPMQ-R scores (transformed to 0-100 scales, mean ± SD) improved from baseline to end of treatment for Efficacy (52.5 ± 17.8 versus 74.8 ± 23.4, p < 0.0001) and Functionality (46.2 ± 22.3 versus 71.3 ± 25.2, p < 0.0001) with no deterioration in Tolerability (80.6 ± 14.7 versus 83.5 ± 17.7, p = 0.12). PPMQ-R Overall Satisfaction score increased from baseline to end of treatment (55.1 ± 23.2 versus 74.6 ± 27.7, p < 0.0001). The percentage of patients (90% confidence interval) confident or very confident in treating migraine attacks increased from 22.2% (15.2, 30.6) at baseline to 57.8% (48.6, 66.6) at end of treatment. Results should be interpreted in the context of the open-label design of the original study.

CONCLUSION

With SDP, triptan users requiring a change in therapy experienced increased efficacy, satisfaction with therapy, and confidence in treatment without deterioration in tolerability.

Pharmacokinetic evaluation of frovatriptan

INTRODUCTION

Migraine is the most common painful neurological disorder, affecting 13% of the general population. Triptans represent a powerful pharmacological tool in acute migraine treatment, however, a significant portion of treated patients cannot have access to this class due to possible adverse affects. Today, a total of seven triptan molecules are available, representing a commonly prescribed migraine treatment. Although there is a need of extensive use of triptans, only 25% of migraine patients are using triptans.

AREAS COVERED

This review includes triptans and evidence for the use of frovatriptan. A systematic approach is used to discuss the pharmacodynamic and pharmacokinetic aspects of frovatriptan, considering the emerging data on the clinical efficacy of frovatriptan in the treatment of migraine and cluster headaches. The data were obtained by searching the following key words in MEDLINE: pharmacokinetic, pharmacodynamic, triptans, frovatriptan, migraine, menstrual migraine, relatively to the period 1988 - 2011.

EXPERT OPINION

Frovatriptan has been developed in order to improve safety and efficacy of triptans. It shows a favorable tolerability and efficacy profile, limited to 24/48-h headache recurrence, when compared with other triptans. Preclinical data suggest that the pharmacokinetic profile of frovatriptan may differ from other available triptans. In fact, among triptans, frovatriptan showed the highest potency at the 5-HT1B receptor (8.2) and the longer half-life (26 h). These parameters determine the clinical properties of frovatriptan; in particular the lowest rate of headache recurrence in comparison with other triptans.

Triptans for the management of migraine

Migraine is a chronic, recurrent, disabling condition that affects millions of people in the US and worldwide. Proper acute care treatment for migraineurs is essential for a full return of function and productivity. Triptans are serotonin (5-HT)(1B/1D) receptor agonists that are generally effective, well tolerated and safe. Seven triptans are available worldwide, although not all are available in every country, with multiple routes of administration, giving doctors and patients a wide choice. Despite the similarities of the available triptans, pharmacological heterogeneity offers slightly different efficacy profiles. All triptans are superior to placebo in clinical trials, and some, such as rizatriptan 10 mg, eletriptan 40 mg, almotriptan 12.5 mg, and zolmitriptan 2.5 and 5 mg are very similar to each other and to the prototype triptan, sumatriptan 100 mg. These five are known as the fast-acting triptans. Increased dosing can offer increased efficacy but may confer a higher risk of adverse events, which are usually mild to moderate and transient in nature. This paper critically reviews efficacy, safety and tolerability for the different formulations of sumatriptan, zolmitriptan, rizatriptan, naratriptan, almotriptan, eletriptan and frovatriptan.

Micellar nanocarriers: potential nose-to-brain delivery of zolmitriptan as novel migraine therapy

PURPOSE

The investigation was aimed at developing micellar nanocarriers for nose-to-brain delivery of zolmitriptan with the objective to investigate the pathway involved in the drug transport.

METHODS

The micellar nanocarrier was successfully formulated and characterized for particle size and shape by multi-angle dynamic light scattering, small angle neutron scattering and cryo-transmission electron microscopy. Toxicity and biodistribution studies were carried out in rat. The distribution of the nasally administered labeled micellar nanocarrier in various regions of the rat brain was determined using the brain localization and autoradiography studies.

RESULTS

Micellar nanocarrier of zolmitriptan, with size of around 23 nm, was successfully formulated. The spherical nature of the nanocarrier was confirmed using DLS, SANS and cryo-TEM. Toxicity studies indicated the safety for administration in the nasal cavity. In vivo biodistribution studies indicated the superiority of the developed nanocarrier for brain targeting when compared with the intravenous and nasal solutions of the drug. Brain localization and autoradiography studies illustrated the distribution of the drug in various regions of the brain and revealed a possible nose-to-brain transport pathway for the labeled drug.

CONCLUSION

The investigation indicated the potential of the developed nanocarrier as an effective new-generation vehicle for brain targeting of zolmitriptan.

Microemulsion based intranasal delivery system for treatment of insomnia

The aim of this investigation was to prepare and characterize microemulsions/mucoadhesive microemulsions of Diazepam (D), Lorazepam (L) and Alprazolam (A), evaluate their pharmacodynamic performances by performing comparative sleep induction studies in male albino rats to assess their role in effective management of insomnia patients. Microemulsions of Diazepam (DME), Lorazepam (LME) and Alprazolam (AME) were prepared by titration method and characterized for drug content, globule size distribution and zeta potential, nasal toxicity and sleep induction. DME, LME and AME were transparent and stable with mean globule size and zeta potential in the range of 95.6 nm to 141.7 nm and -2.205 to -0.111 mV respectively. The prepared microemulsions exhibited reversible nasal toxicity. Onset of sleep and duration of sleep were observed in the following order: Lorazepam > Alprazolam>Diazepam. Faster onset of sleep following intranasal administration of microemulsions (<20 min) compared to oral administration (29-33 min) and control group (>45 min) for all three drugs suggested selective nose-to-brain transport of drug(s). Intranasal administration of microemulsion based formulations resulted in even faster onset of sleep (<12 min) with intranasal mucoadhesive microemulsion(s) resulting in fastest onset of sleep (<9 min). Duration of sleep was longest with the intranasal mucoadhesive microemulsions. These results are suggestive of larger extent of distribution of drug(s) to brain after intranasal administration of mucoadhesive microemulsion(s). These results are further corroborated with by loss or rightening reflex and startle reflex at earlier time points (within 10 min and 15 min respectively) with mucoadhesive microemulsions. Thus, the results of this investigation indicated rapid and larger extent of drug transport to the rat brain resulting in rapid induction of sleep followed by prolonged duration of sleep in rats following intranasal administration of mucoadhesive microemulsion(s). However, the role of microemulsion based formulations developed in this investigation in clinical practice can only be established after animal studies in two different animal models followed by extensive clinical trials.

Migraine in the triptan era: progresses achieved, lessons learned and future developments

Triptans, serotonin 5-HT1B/1D receptor agonists, more than revolutionizing the treatment of migraine, stimulated also ground breaking research that provided insights into the anatomy, physiology, and molecular pharmacology of migraine. This knowledge, in turn, is stimulating research on new mechanisms of action for the treatment of migraine. Accordingly, it is opportune to critically review the main advances in migraine science that happened in the triptan era. Herein we first review and conceptualize some of the progresses achieved in migraine science during the triptan era. We then review the class of the triptans - mechanism of action and clinical evidence. We close by briefly discussing the class of CGRP receptor antagonists, which is currently being developed for the acute treatment of migraine.

Intranasal mucoadhesive microemulsions of zolmitriptan: Preliminary studies on brain-targeting

The aim of this investigation was to prepare microemulsions containing zolmitriptan (ZT) for rapid drug delivery to the brain to treat acute attacks of migraine and to characterize microemulsions and evaluate biodistribution in rats. Zolmitriptan microemulsions (ZME) were prepared using the titration method and were characterized for globule size distribution and zeta potential. ZT was radiolabeled using (99m)Tc (technetium) and radiolabeled-drug formulations of ZT were used to carry out biodistribution of drug in the brain of Swiss albino rats after intranasal and intravenous administration. The pharmacokinetic parameters, drug targeting efficiency (%DTE) and direct nose-to-brain drug transport (%DTP) were calculated. Brain scintigraphy imaging in rats were also performed to ascertain the uptake of drug into the brain. ZME were transparent and stable with mean globule size of 35 +/- 25 nm and zeta potential of - 38- - 52 mV. (99m)Tc-labeled-drug formulations of ZT were found to be stable and suitable to perform in vivo studies. Following intranasal administrations of zolmitriptan mucoadhesive microemulsion (ZMME), ZME, Zolmitriptan solution (ZS) and intravenous administration of ZS, brain/blood uptake ratios at 0.50 h were found to be 0.70, 0.56, 0.27 and 0.13, respectively, indicating effective brain-targeting following intranasal administration of ZMME. Comparing intranasal administration of ZMME with intravenous administration of ZME, the %DTE and %DTP were found higher indicating effective drug transport following intranasal administration and highest brain-targeting following ZMME administration. Rat brain scintigrams showed substantial uptake of drug into the brain after intranasal administration of ZMME. Studies of this investigation conclusively demonstrated rapid and larger extent of transport into the rat brain following intranasal administration of ZMME and can play a promising role in the treatment of acute attacks of migraine.

Dihydroergotamine for Early and Late Treatment of Migraine With Cutaneous Allodynia: An Open-Label Pilot Trial

OBJECTIVE

To explore whether dihydroergotamine (D.H.E. 45) is equally effective and safe for migraine with allodynia, when administered either early or late in an attack.

BACKGROUND

Central sensitization may account for the extracranial tenderness and cutaneous allodynia that can occur with migraine. Once allodynia is established, triptans are less effective. Dihydroergotamine is often effective for patients whose refractory headaches have failed prior triptan therapy.

METHODS

In this single-center, open-label pilot trial, patients with episodic migraine associated with cutaneous allodynia were treated on 2 occasions with dihydroergotamine 1.0 mg intramuscularly. One attack was treated within 2 hours (early) and a second attack at 4 hours (late) after the onset of throbbing pain. Headache pain and any associated symptoms, subjective cutaneous allodynia, and mechanical (brush) allodynia were assessed. All data were analyzed using the Fisher's exact test.

RESULTS

Thirteen patients met the entry criteria; however, data from only 9 patients, those who completed treatment for 2 migraine attacks, were used to evaluate the efficacy and safety of dihydroergotamine. Whether they took dihydroergotamine early or late in the attack, most patients (>55%) had headache relief within 2 hours, and at least 44% of patients achieved headache-free status by 8 hours postdose. Subjective cutaneous allodynia started to decline after 30 minutes postdose in the early treated group and after 120 minutes postdose in the late-treated group. Brush allodynia began to decline after 15 minutes postdose in the early treated group and after 90 minutes postdose in the late-treated group. Six of 9 patients (67%) reported at least 1 adverse event.

CONCLUSIONS

The results of this pilot trial provide proof of concept for the headache-relief benefit of dihydroergotamine in patients with migraine headache and allodynia. A large, placebo-controlled trial of dihydroergotamine in allodynic patients is warranted.

Preliminary brain-targeting studies on intranasal mucoadhesive microemulsions of sumatriptan

The aim of this investigation was to prepare microemulsions containing sumatriptan (ST) and sumatriptan succinate (SS) to accomplish rapid delivery of drug to the brain in acute attacks of migraine and perform comparative in vivo evaluation in rats. Sumatriptan microemulsions (SME)/sumatriptan succinate microemulsions (SSME) were prepared using titration method and characterized for drug content, globule size and size distribution, and zeta potential. Biodistribution of SME, SSME, sumatriptan solution (SSS), and marketed product (SMP) in the brain and blood of Swiss albino rats following intranasal and intravenous (IV) administrations were examined using optimized technetium-labeled (99mTc-labeled) ST formulations. The pharmacokinetic parameters, drug targeting efficiency (DTE), and direct drug transport (DTP) were derived. Gamma scintigraphy imaging of rat brain following IV and intranasal administrations were performed to ascertain the localization of drug. SME and SSME were transparent and stable with mean globule size 38±20 nm and zeta potential between -35 to -55 mV. Brain/blood uptake ratios at 0.5 hour following IV administration of SME and intranasal administrations of SME, SMME, and SSS were found to be 0.20, 0.50, 0.60, and 0.26, respectively, suggesting effective transport of drug following intranasal administration of microemulsions. Higher DTE and DTP for mucoadhesive microemulsions indicated more effective targeting following intranasal administration and best brain targeting of ST from mucoadhesive microemulsions. Rat brain scintigraphy endorsed higher uptake of ST into the brain. Studies conclusively demonstrated rapid and larger extent of transport of microemulsion of ST compared with microemulsion of SS, SMP, and SSS into the rat brain. Hence, intranasal delivery of ST microemulsion developed in this investigation can play a promising role in the treatment of acute attacks of migraine.

Triptans induce vasoconstriction of human arteries and veins from the thoracic wall

A common side effect of migraine treatment with triptans is chest symptoms. The origin of these symptoms is not known. The aim of the present study was to examine the vasocontractile effect of triptans in human arteries and veins from the thoracic wall and in coronary artery bypass grafts. In vitro pharmacology experiments showed that the 5-hydroxytryptamine (5-HT) type 1B and 1D receptor agonists, eletriptan, naratriptan, rizatriptan, sumatriptan, and zolmitriptan, induced vasoconstriction in the thoracic blood vessels from 38% to 57% of the patients. 5-carboxamidotryptamine (5-CT) and sumatriptan elicited a vasoconstriction that was antagonized by the 5-HT1B receptor antagonist SB224289, whereas the 5-HT1D receptor antagonist BRL115572 had no effect. 5-HT induced a contraction that was inhibited by the 5-HT2A receptor antagonist ketanserin. 5-HT2A, 5-HT1B, and 5-HT1D receptor mRNA levels were detected by real-time PCR in all blood vessels studied. In conclusion, triptans induce vasoconstriction in arteries and veins from the thoracic wall, most likely by activation of 5-HT1B receptors. This response could be observed in only 38% to 57% of the patients, which may provide an explanation for why a similar number of patients experience chest symptoms as a side effect of migraine treatment with triptans.

Sinus headache: a neurology, otolaryngology, allergy, and primary care consensus on diagnosis and treatment

Sinus headache is a widely accepted clinical diagnosis, although many medical specialists consider it an uncommon cause of recurrent headaches. The inappropriate diagnosis of sinus headache can lead to unnecessary diagnostic studies, surgical interventions, and medical treatments. Both the International Headache Society and the American Academy of Otolaryngology-Head and Neck Surgery have attempted to define conditions that lead to headaches of rhinogenic origin but have done so from different perspectives and in isolation of each other. An interdisciplinary ad hoc committee convened to discuss the role of sinus disease as a cause of headache and to review recent epidemiological studies that suggest sinus headache (headache of rhinogenic origin) and migraine are frequently confused with one another. This committee reviewed available scientific evidence from multiple disciplines and concluded that considerable research and clinical study are required to further understand and delineate the role of nasal pathology and autonomic activation in migraine and headaches of rhinogenic origin. However, this group agreed that greater diagnostic and therapeutic attention needs to be given to patients with sinus headaches.

Evaluating the triptans

The debilitating effect of migraine has fueled the search for more specific agents to treat its characteristic and associated symptoms. Second-generation oral triptans have shown an improved efficacy profile in comparison with the pioneer sumatriptan and with the over-the-counter medications and prescription analgesics that have been staples of migraine treatment. Although all triptans exert effects through the 5-hydroxytryptamine 1B/1D receptors, each triptan has distinctive pharmacokinetic properties that determine its efficacy and tolerability profile. Empirical findings based on clinical trials have led to associations between triptan pharmacology and efficacy. With the expanded treatment choices, the onus is on healthcare providers (especially primary care physicians, who see the majority of patients with migraine) to determine which treatment has an efficacy profile that best suits the individual patient's needs. Patients prefer pharmacotherapy with a rapid onset of action that facilitates complete pain relief and no recurrence. Data from published comparator trials, based on commonly used efficacy end points and pharmacokinetic properties underlying patient-preferred outcomes, are reviewed in this article.

Evaluating the safety and tolerability profile of acute treatments for migraine

Among the medications that have been used as acute treatments for migraine are nonspecific agents, including nonsteroidal anti-inflammatory drugs (NSAIDs), analgesics (either single or combination), and narcotics, as well as migraine-specific medications, including ergot alkaloids and triptans (5-hydroxytryptamine 1B/1D agonists). All of these drugs have side effects that vary in type and severity. Side effects of nonspecific medications, including gastrointestinal (GI) and renal effects with NSAIDs and cognitive effects and the potential for abuse with narcotics and butalbital-containing medications, have been documented over time, as these medications have been used for various indications. Side effects of the migraine-specific medications include GI and vascular symptoms with the ergots; for the triptans, they include chest and neurologic symptoms. Although adverse events are reported fairly frequently in patients receiving triptans, they are usually mild, and few patients discontinue therapy because of them. The most serious adverse events are cardiovascular. Because of potential vasoconstrictor effects--mild and transient increases in blood pressure and mild and transient effects on coronary artery tone--triptans as a class are contraindicated in patients with established or clinically suspected cardiovascular disease, specifically ischemic heart disease and uncontrolled hypertension. Other adverse events, including the potential for drug-drug interactions, are less common. Therefore, consideration should be given to the tolerability and safety of medications before their use as abortive medications for the treatment of migraine headache.