Buspirone and Zolmitriptan Combination for Dyskinesia: A Randomized, Controlled, Crossover Study

BACKGROUND

Preclinical evidence suggests that co-administration of the 5-HT1A agonist buspirone and the 5-HT1B/1D agonist zolmitriptan act synergistically to reduce dyskinesia to a greater extent than that achieved by either drug alone.

OBJECTIVES

Assess the therapeutic potential of a fixed-dose buspirone and zolmitriptan combination in Parkinson's disease (PD) patients with levodopa-induced dyskinesia.

METHODS

Single-center, randomized, placebo-controlled, two-way crossover study (NCT02439203) of a fixed-dose buspirone/zolmitriptan regimen (10/1.25 mg three times a day) in 30 patients with PD experiencing at least moderately disabling peak-effect dyskinesia.

RESULTS

Seven days of treatment with buspirone/zolmitriptan added to levodopa significantly reduced dyskinesia as assessed by Abnormal Involuntary Movement Scale scores versus placebo (mean treatment effect vs. placebo: -4.2 [-6.1, -2.3]) without significantly worsening Unified Parkinson's Disease Rating Scale (UPDRS) Part III (ON) scores (mean treatment effect vs. placebo: 0.6 [-0.1, 1.3]). No serious adverse events were reported.

CONCLUSIONS

In this proof-of-concept study, addition of buspirone/zolmitriptan to the patients' PD medication regimen significantly reduced dyskinesia severity without worsening motor function. © 2024 International Parkinson and Movement Disorder Society.

Beneficial effect of 5-HT1b/1d agonist on Parkinson's disease by modulating glutamate and reducing deposition of α-synuclein

The given investigation examined the neuroprotection role of 5-HT1b/1d agonist in reserpine induced Parkinson's disease (PD) in male Wistar rats. PD was induced in rats by reserpine at 5 mg/kg ip for 3 days and thereafter the rats were provided with the following treatments for 4 days, zolmitriptan (ZLM) group (30 mg/kg ip); STD group (levodopa + carbidopa, 200 + 5 mg/kg ip); ZLM + GA group (zolmitriptan, 30 mg/kg ip and glutamic acid, 1.5 mg/kg); ZLM + DX group (zolmitriptan, 30 mg/kg ip and dextromethorphan, 20 mg/kg ip). All the groups were then assessed for cognitive and motor functions at the end of the protocol. Moreover, oxidative stress parameters and histopathological changes were observed in rats of all treatment groups. Deposition of α-synuclein in the brain tissue was observed by silver staining. Data of this investigation revealed that motor and cognitive functions were improved in the ZLM-treated group compared with the negative control group, which was observed to be reversed in ZLM + GA group. Treatment with ZLM ameliorated oxidative stress and histopathological changes in the brain tissue of PD rats. Further, ZLM reduced the deposition of α-synuclein in PD rats, which reversed in ZLM + GA-treated group. This study concludes by stating that 5-HT1b/1d agonist can prevent neurodegeneration and reduce oxidative stress in PD rats. The probable underlying mechanism of such an effect of 5-HT1b/1d agonist could be by regulating the deposition of α-synuclein and reducing the expression of NMDA receptor.

Metabolism of sumatriptan revisited

Scientific literature describes that sumatriptan is metabolized by oxidative deamination of its dimethylaminoethyl residue by monoamine oxidase A (MAO A) and not by cytochrome P450 (CYP)-mediated demethylation, as is usual for such structural elements. Using recombinant human enzymes and HPLC-MS analysis, we found that CYP enzymes may also be involved in the metabolism of sumatriptan. The CYP1A2, CYP2C19, and CYP2D6 isoforms converted this drug into N-desmethyl sumatriptan, which was further demethylated to N,N-didesmethyl sumatriptan by CYP1A2 and CYP2D6. Otherwise, sumatriptan and its two desmethyl metabolites were metabolized by recombinant MAO A but not by MAO B to the corresponding acetaldehyde, with sumatriptan being only a poor substrate for MAO A compared to the N-demethylated and the N,N-didemethylated derivatives.

Two Spectroscopic Methods for Estimation of Anti-migraine Medications; Sumatriptan and Zolmitriptan Based on Nucleophilic Substitution Reaction

Sensitive and selective spectrophotometric and spectrofluorimetric methods have been developed for estimation of two antimigraine drugs namely sumatriptan succinate and zolmitriptan. These methods depend on producing a yellow-colored product after the reaction of the two drugs with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl). The reaction products exhibit maximum absorbance at 481 nm in borate buffer of pH 9 and fluorescence emission peak at 540 nm after excitation at 470 nm for the two drugs. The linear ranges were 5-60 μg/mL for SUM and 5-50 μg/mL for ZOL in the spectrophotometric method (method I), while 0.4-4 μg/mL for SUM and 0.5-5 μg/mL for ZOL in the spectrofluorimetric method (method II). The methods validity was assessed according to ICH guidelines. Statistical analysis of the results obtained from the proposed and comparison methods confirmed that the proposed methods are highly accurate and precise. The suggested methods could be used for the determination of the mentioned drugs in both pure and tablets.

Activation of 5-HT 1b/d receptor restores the cognitive function by reducing glutamate release, deposition of β-amyloid and TLR-4 pathway in the brain of scopolamine-induced dementia in rat

OBJECTIVES

This study evaluates the effect of 5-HT 1b/d agonist on cognitive function in scopolamine (SPN)-induced dementia in the rat.

METHODS

Dementia was induced by administration of SPN 2 mg/kg/day, intraperitoneally, for a duration of 21 days. The effect of zolmitriptan (ZMT) 30 mg/kg, intraperitoneally, was observed on cognitive function, and the parameters of oxidative stress like malondialdehyde (MDA) level, nitric oxide (NO), superoxide dismutase (SOD) and glutathione peroxidase (GPX) were estimated at the end. Histopathology study of brain tissue was performed for the determination of β-amyloid peptide, and qRT-PCR was used to determine the mRNA expression of Toll-like receptor 4 (TLR-4), IL-17 and β-amyloid.

KEY FINDINGS

Data of the study suggested that treatment with ZMT alone and in combination with DMP (dextromethorphan) significantly (P < 0.01) decreases the escape latency in conditioned avoidance response (CAR) and transfer latency in elevated plus maze (EPM) as compared with negative control group. Moreover, the result of Morris water maze (MWM) shows an increase in retention time and a decrease in escape latency in ZMT alone and in combination with DMP-treated group of SPN-induced dementia than in the negative control group. There was a significant decrease in MDA and NO and increase in SOD and GPX in the brain tissues of ZMT and ZMT + DMP-treated group than negative control group. Histopathology study also suggested that the concentration of Aβ peptide decreases in the brain tissues in ZMT and ZMT + DMP-treated group than the negative control group. Moreover, ZMT treatment ameliorates the altered mRNA expression of TLR-4 and IL-17 in the brain tissue of SPN-induced dementia rat.

CONCLUSIONS

In conclusion, ZMT restores the cognitive functions and impaired memory in SPN-induced dementia in the rat by decreasing oxidative stress and Aβ peptide in the brain tissue of rat.

Intranasal Zolmitriptan-Loaded Bilosomes with Extended Nasal Mucociliary Transit Time for Direct Nose to Brain Delivery

This study aimed at delivering intranasal zolmitriptan directly to the brain through preparation of bilosomes incorporated into a mucoadhesive in situ gel with extended nasal mucociliary transit time. Zolmitriptan-loaded bilosomes were constructed through a thin film hydration method applying Box–Behnken design. The independent variables were amount of sodium deoxycholate and the amount and molar ratio of cholesterol/Span^® 40 mixture. Bilosomes were assessed for their entrapment efficiency, particle size and in vitro release. The optimal bilosomes were loaded into mucoadhesive in situ gel consisting of poloxamer 407 and hydroxypropyl methylcellulose. The systemic and brain kinetics of Zolmitriptan were evaluated in rats by comparing intranasal administration of prepared gel to an IV solution. Statistical analysis suggested an optimized bilosomal formulation composition of sodium deoxycholate (5 mg) with an amount and molar ratio of cholesterol/Span^® 40 mixture of 255 mg and 1:7.7, respectively. The mucoadhesive in situ gel containing bilosomal formulation had a sol-gel temperature of 34.03 °C and an extended mucociliary transit time of 22.36 min. The gelling system possessed enhanced brain bioavailability compared to bilosomal dispersion (1176.98 vs. 835.77%, respectively) following intranasal administration. The gel revealed successful brain targeting with improved drug targeting efficiency and direct transport percentage indices. The intranasal delivery of mucoadhesive in situ gel containing zolmitriptan-loaded bilosomes offered direct nose-to-brain drug targeting with enhanced brain bioavailability.

Metabolic activation of zolmitriptan mediated by CYP2D6

Zolmitriptan (ZOL), a member of triptans, has been used for the treatment of migraine with definite therapeutic effects. However, several cases of liver injury associated with ZOL have been reported and the underlying mechanisms remain unclear.The present study aimed to investigate the metabolic activation of ZOL in vitro and in vivo. ZOL-derived glutathione (GSH) and N-acetyl cysteine (NAC) conjugates were detected in rat liver microsomal incubations. In addition, the GSH and NAC conjugates were also found in bile and urine of rats given ZOL, respectively.ZOL-derived GSH conjugate M1 was also observed in ZOL-treated rat primary hepatocytes, and the formation of M1 was inhibited by pre-cultured with quinidine (a selective inhibitor of CYP2D6). Combining with recombinant P450 enzymes incubations, we found that CYP2D6 was the predominant enzyme responsible for the metabolic activation of ZOL.ZOL can be metabolized to an α,β-unsaturated imine intermediate by CYP2D6. Pre-treatment of primary hepatocytes with quinidine was able to reverse ZOL-induced cytotoxicity. The finding facilitates the understanding of the mechanisms involved in ZOL-associated liver adverse reactions.

Quality by Design Approach for Preparation of Zolmitriptan/Chitosan Nanostructured Lipid Carrier Particles - Formulation and Pharmacodynamic Assessment

Purpose

Zolmitriptan (ZT) is a selective serotonin agonist that is used for the treatment of migraine. It belongs to BCS class III with high solubility and low permeability. Besides, the drug is subjected to pre-systemic metabolism. Accordingly, new Zolmitriptan/chitosan nanostructured lipid carriers (ZT/CT NLCs) coated with Tween 80 (stealthy layer) have been developed to overcome such demerits.

Methods

The NLCs were developed by combining ultrasonication and double emulsion (w/o/w) techniques. The lipids were Gelucire and Labrasol. Herein, the quality by design (2³ full factorial design) was scrupulously followed, where critical process parameters and critical quality attributes were predefined. The optimized formulation (F8) was fully characterized with respect to entrapment efficiency (%EE), percentage yield (% yield), particle size, size distribution (PDI), zeta potential (ZP), morphological appearance (TEM). In vitro release, stability study and pharmacodynamic evaluations were also assessed. The optimized freeze dried formula was dispensed in in situ gelling hard gelatin capsule encompassing pectin and guar gum for further in vitro and pharmacodynamic evaluations.

Results

The optimized spherical nanoparticles experienced high percentage EE and yield (78.14% and 60.19%, respectively), low particle size and PDI (343.87 nm and 0.209, respectively), as well as high negative ZP (−25.5 mV). It showed good physical stability at refrigerated conditions. The NLCs dispensed in in situ gelling hard gelatin capsule comprising pectin and guar gum experienced sustained release for 30 h and significantly maintained the pharmacological effect in mice up to 8 h (p < 0.001).

Conclusion

ZT, a BCS class III drug that suffers from poor permeability and pre-systemic metabolism, was successfully maneuvered as nanostructured lipid carrier particles (NLCs). The incorporation of the NLCs in in situ gelling hard gelatin capsules fulfilled a dual function in increasing permeability, as well as sustaining the pharmacodynamic effect. This result would open new vistas in improving the efficacy of other class III drugs.

Development of a novel zolmitriptan intracutaneous microneedle system (Qtrypta™) for the acute treatment of migraine

M207 is an investigational intracutaneous microneedle therapeutic system for nonoral zolmitriptan delivery. In a Phase I trial, M207 provided faster absorption with a higher 2 h exposure than oral zolmitriptan. In the pivotal trial evaluating efficacy, tolerability and safety in moderate-to-severe migraine attacks, M207 3.8 mg was superior to placebo in providing freedom from headache pain (42 vs 14%) and freedom from most bothersome symptom (68 vs 43%) 2 h post-dose. Treatment-emergent adverse events were mild and transient and most commonly concerned the application site. In post hoc analyses: pain freedom was sustained in approximately 1/3 of patients; efficacy was observed in migraine headaches that are typically more difficult to treat.

In-vitro and in-vivo respiratory deposition of a developed metered dose inhaler formulation of an anti-migraine drug

Enhancement of zolmitriptan bioavailability through development of micronized zolmitriptan pressurized metered dose inhaler (MDI) as an alternative to its traditional drug delivery systems. A reversed phase HPLC method for zolmitriptan determination was developed and evaluated. Micronized zolmitriptan MDI formulations were prepared using two different propellants. The prepared formulations were evaluated for mean shot weight, drug content, and leakage rate in addition to in-vitro deposition using next generation impactor where mass median aerodynamic diameter (MMAD), geometric standard deviation (GSD), fine particle dose, fine particle fraction (FPF), emitted dose (ED), and dispersibility were determined. The selected formulation was evaluated for in-vivo bronchial absorption in rats. The physicochemical characters of the prepared formulations were found to be dependent mainly on the vapor pressure of the used propellant. MDI formulation prepared with HFA 134a propellant was found to have the lowest MMAD (3.47 ± 0.65) with GSD of 2.3 ± 0.4. It also had the highest FPF (41.9), ED (89.26 ± 2.35) with dispersibility of 46.9%. This formulation, when applied to rats, resulted in faster T_max (27 ± 5 min) with higher C_max (1236 ± 116 ng/mL) and AUC_(0-12) (3375 ± 482 ng/mL·h) over the oral tablet. Its relative bioavailability was 72.7% which was 1.25 times higher than the oral tablet relative bioavailability. Zolmitriptan MDI formulation was developed using micronized zolmitriptan powder without further modification or particle engineering. The developed formulation using HFA 134a propellant could be favorable alternative, with enhanced bioavailability, to zolmitriptan oral tablet for acute migraine treatment.

Assessment Of Spanlastic Vesicles Of Zolmitriptan For Treating Migraine In Rats

OBJECTIVE

To develop and evaluate zolmitriptan spanlastics (Zol SLs) as a brain-targeted antimigraine delivery system. Spanlastics (SLs) prepared using span 60: tween 80 (70:30%, respectively) gave the highest percentage of entrapment efficiency (EE%).

MATERIALS AND METHODS

A total of 60 adult male Wistar albino rats were divided into six groups (n=10 rats/group). Group 1 (Control) comprised rats serving as a negative control. Group 2 was treated with glyceryl trinitrate (NTG) and served as the positive control. Groups 3 (NTG+Zol com), Group 4 (NTG+Zol sol) and Group 5 (NTG+Zol SLs) received commercial zolmitriptan orally, zolmitriptan solution intranasally and Zol SLs F5 intranasally, respectively, 30 min before NTG. Group 6 (Zol SLs) comprised normal rats that received only Zol SLs intranasally.

RESULTS

We found decreased Tmax, increased Cmax, AUC0-6, AUC0-∞ and ameliorated behaviour in rats (head scratching) treated with intranasal SLs compared to oral commercial zolmitriptan.

CONCLUSION

Our study substantiates the enhanced efficacy of Zol SLs in brain targeting for migraine treatment.

Investigation of Effect of Isopropyl Palmitate on Drug Release from Transdermal Patch and Molecular Dynamics Study

Chemical penetration enhancers are widely used in transdermal drug delivery system. However, few studies have focused on changes of concentration in chemical penetration enhancers. In this study, the effect of concentrations of enhancers on drug release and its mechanism were investigated. Zolmitriptan (ZOL) was used as a model drug and isopropyl palmitate (IPP) was used as a model enhancer to investigate drug release behaviors in pressure-sensitive adhesives (PSAs). The IPP concentrations were 2, 5, 10, 12, and 15%. Drug release percents increased by 4.8, 11.5, 16, 15.1, and 14.8%, respectively. Interestingly, the linear relationship between concentrations of IPP and release percents was improved in the 0-10% and remained unchanged in the 10-15%. Moreover, thermal and rheology studies were performed to investigate changes of the fluidity of PSAs. FT-IR and molecular dynamics simulation were conducted to confirm the interaction strength among ZOL, IPP, and PSAs. The results elucidated that IPP increased fluidity of PSAs and vied for drug from PSAs. As a result, the interaction among three components played a major role in changing release behaviors of ZOL, but the increased fluidity only worked in the concentration of less than 10%.

Efficacy of ADAM Zolmitriptan for the Acute Treatment of Difficult-to-Treat Migraine Headaches

Objective

To understand the efficacy of zolmitriptan applied with Adhesive Dermally Applied Microarray (ADAM) in treating types of migraine (those with severe headache pain, the presence of nausea, treatment ≥2 hours after migraine onset, or migraine present upon awakening) that are historically considered to be less responsive to oral medications.

Background

ADAM is an investigational system for intracutaneous drug administration. In a pivotal Phase 2b/3 study (ZOTRIP, N = 321 in the modified intention‐to‐treat population), ADAM zolmitriptan 3.8 mg provided superior pain freedom and freedom from patients’ usual most bothersome associated symptom (MBS), compared with placebo at 2 hours post‐dose. We undertook a post hoc analysis of data from the ZOTRIP trial to examine these same outcomes in subsets of patients whose migraine characteristics have been associated with poorer outcomes when treated with oral medications.

Methods

The ZOTRIP trial was a multicenter, randomized, double‐blind, placebo‐controlled, parallel group Phase 2b/3 study conducted at 36 sites in the United States. Presented here are post hoc subgroup analyses of patients with nausea (n = 110) or severe pain (n = 72) at baseline, those whose treatment was delayed 2 or more hours after onset (n = 75), and those who awoke with migraine (n = 80). The Cochran–Mantel–Haenszel test was used to assess whether patients in the ADAM zolmitriptan 3.8 mg group had superior treatment outcomes compared with placebo.

Results

In patients with nausea, 2‐hour pain freedom was achieved in 44% (26/59) in the ADAM zolmitriptan 3.8 mg group and 14% (7/51) in the placebo group (P = .005) (odds ratio = 5.11, 95% CI: 1.96–13.30), and 2‐hour MBS freedom was achieved in 68% (40/59) in the active treatment group and 45% (23/51) of those receiving placebo (P = .009) (odds ratio = 2.86, 95% CI: 1.28–6.43). For those with severe pain, corresponding pain‐free values were 26% (10/39) and 15% (5/33) (P = .249) (odds ratio = 2.14, 95% CI: 0.60–7.62), and MBS‐free values were 64% (25/39) and 42% (14/33) (P = .038) (odds ratio = 2.86, 95% CI: 1.05–7.79). Among participants who awoke with migraine, 44% (16/36) and 16% (7/44) were pain‐free in the ADAM zolmitriptan 3.8 mg and placebo groups, respectively (P = .006) (odds ratio = 4.29, 95% CI: 1.50–12.31), and 72% (26/36) vs 39% (17/44) were MBS‐free, respectively (P = .003) (odds ratio = 4.40, 95% CI: 1.61–12.05). In those whose treatment was delayed ≥2 hours, pain freedom in the active treatment group and placebo group were 33% (12/36) and 10% (4/39), respectively (P = .017) (odds ratio = 4.33, 95% CI: 1.24–15.10), and MBS freedom was achieved in 69% (25/36) and 41% (16/39), respectively, in the delayed treatment group (P = .014) (odds ratio = 3.37, 95% CI: 1.27–8.95). No significant effects (overall interaction P = .353) were observed in logistical regression models of treatment by subgroup interaction.

Conclusion

Severe pain, delayed treatment, awakening with a headache, and the presence of nausea are factors that predict a poorer response to acute migraine treatment. In these post hoc analyses of subgroups of patients with each of these characteristics in the ZOTRIP trial, participants receiving ADAM zolmitriptan 3.8 mg displayed nearly uniformly better headache responses (2‐hour headache freedom and 2‐hour MBS freedom) compared with those who received placebo.

Use of Most Bothersome Symptom as a Coprimary Endpoint in Migraine Clinical Trials: A Post-Hoc Analysis of the Pivotal ZOTRIP Randomized, Controlled Trial

Objective

To better understand the utility of using pain freedom and most bothersome headache‐associated symptom (MBS) freedom as co‐primary endpoints in clinical trials of acute migraine interventions.

Background

Adhesive dermally applied microarray (ADAM) is an investigational system for intracutaneous drug administration. The recently completed pivotal Phase 2b/3 study (ZOTRIP), evaluating ADAM zolmitriptan for the treatment of acute moderate to severe migraine, was one of the first large studies to incorporate MBS freedom and pain freedom as co‐primary endpoints per recently issued guidance by the US Food and Drug Administration. In this trial, the proportion of patients treated with ADAM zolmitriptan 3.8 mg, who were pain‐free and MBS‐free at 2 hours post‐dose, was significantly higher than for placebo.

Methods

We undertook a post‐hoc analysis of data from the ZOTRIP trial to examine how the outcomes from this trial compare to what might have been achieved using the conventional co‐primary endpoints of pain relief, nausea, photophobia, and phonophobia.

Results

Of the 159 patients treated with ADAM zolmitriptan 3.8 mg or placebo, prospectively designated MBS were photophobia (n = 79), phonophobia (n = 43), and nausea (n = 37). Two‐hour pain free rates in those with photophobia as the MBS were 36% for ADAM zolmitriptan 3.8 mg and 14% for placebo (P = .02). Corresponding rates for those with phonophobia as the MBS were 14% and 41% (P = .05). For those whose MBS was nausea, corresponding values were 56% and 16%, respectively (P = .01). Two‐hour freedom from the MBS for active drug vs placebo were 67% vs 35% (P < .01) for photophobia, 55% vs 43% (P = .45) for phonophobia, and 89% vs 58% for nausea (P = .04). MBS freedom but not pain freedom was achieved in 28%. Only 1 patient (1%) achieved pain freedom, but not MBS freedom. The proportion with both pain and MBS freedom was highest (56%) among those whose MBS was nausea.

Conclusion

In this study, the use of MBS was feasible and seemed to compare favorably to the previously required 4 co‐primary endpoints.

Randomized, double-blind, placebo-controlled, parallel-group, multi-center study of the safety and efficacy of ADAM zolmitriptan for the acute treatment of migraine

Objective To determine the efficacy, tolerability, and safety of ascending doses of Adhesive Dermally-Applied Microarray (ADAM) zolmitriptan versus placebo for acute migraine treatment. Background ADAM is a novel patient-administered system for intracutaneous drug administration. In a phase 1 pharmacokinetic study, zolmitriptan administered using ADAM had much faster absorption than oral administration with higher exposure in the first two hours. Methods This was a multicenter, randomized, double-blind, placebo-controlled, parallel-group Phase 2b/3 study evaluating ADAM zolmitriptan 1 mg, 1.9 mg, and 3.8 mg versus placebo. Co-primary endpoints were pain freedom and freedom from most bothersome other migraine-associated symptom 2 hours post-dose. Results Of patients treated with ADAM zolmitriptan 3.8 mg or placebo, 41.5% and 14.2%, respectively were pain-free 2 hours post-dose ( p = 0.0001) and 68.3% and 42.9% were free from their most bothersome other symptom ( p = 0.0009). Due to the fixed sequential testing methodology, formal statistical significance was not established for secondary endpoints. However, the proportion of patients who were photophobia-free, phonophobia-free, and nausea-free at 2 hours post-dose was higher in the ADAM zolmitriptan 3.8 mg group compared with placebo, as were the percentages of patients who were pain-free, and who experienced pain relief up to 48 hours post-dose. Systemic adverse events were consistent with previous triptan trials, and included dizziness, paresthesia, muscle tightness, and nausea, all of which occurred in < 5% of patients in any group. Application site reactions were generally mild and resolved within 48 hours, although erythema and bruising persisted for longer periods in some patients. Conclusion ADAM zolmitriptan 3.8 mg provides effective relief of migraine headache and associated most bothersome symptoms compared with placebo, and is well-tolerated. ClinicalTrials.gov NCT02745392.

Population Pharmacokinetic Analysis of Zolmitriptan and Its Metabolite in Adults and Adolescents to Support Dose Selection in Children With Migraine

Zolmitriptan is a serotonin (5-HT) _1B/1D receptor agonist effective for the treatment of migraine. This analysis aimed to develop a population pharmacokinetic (PK) model for zolmitriptan and its active metabolite in adults and adolescents and provide appropriate dosing regimens to be used in clinical trials for children 6-11 years old. The data from a single-dose clinical study of 5.0-mg zolmitriptan nasal spray (ZNS) conducted in adult and adolescent patients with migraine between migraine attacks was applied. Similar plasma concentration profiles of zolmitriptan and its metabolite, 183C91, were observed in adults and adolescents. A 1-compartment model with first-order absorption and first-order elimination reasonably described the zolmitriptan PK. With a portion of elimination of zolmitriptan being treated as the conversion from zolmitriptan to 183C91, the disposition of 183C91 was described by a 1-compartment model with first-order elimination. The estimated typical apparent volume of distribution and clearance of zolmitriptan were 136 L and 121 L/h, respectively, with 56.5% and 42.6% between-subject variability, respectively. Based on the simulation results with the final population PK model, a body weight-based dosing scheme of 5.0 and 2.5 mg ZNS in children greater than and less than 50 kg is recommended to achieve exposures similar to those of the adult and adolescent population administered 5.0 mg ZNS. The recommended doses for children to achieve exposure similar to that observed in adults given 2.5 mg ZNS are 2.5 mg (≥50 kg) and 1.0 mg (15-50 kg). These dosing regimens could be used in future clinical trials.

Preclinical Evidence That 5-HT1B Receptor Agonists Show Promise as Medications for Psychostimulant Use Disorders

BACKGROUND

5-HT1B receptor agonists enhance cocaine intake during daily self-administration sessions but decrease cocaine intake when tested after prolonged abstinence. We examined if 5-HT1B receptor agonists produce similar abstinence-dependent effects on methamphetamine intake.

METHODS

Male rats were trained to self-administer methamphetamine (0.1 mg/kg, i.v.) on low (fixed ratio 5 and variable ratio 5) and high (progressive ratio) effort schedules of reinforcement until intake was stable. Rats were then tested for the effects of the selective 5-HT1B receptor agonist, CP 94,253 (5.6 or 10 mg/kg), or the less selective but clinically available 5-HT1B/1D receptor agonist, zolmitriptan (10 mg/kg), on methamphetamine self-administration both before and after a 21-day forced abstinence period during which the rats remained in their home cages.

RESULTS

The inverted U-shaped, methamphetamine dose-response function for intake on the fixed ratio 5 schedule was shifted downward by CP 94,253 both before and after abstinence. The CP 94,253-induced decrease in methamphetamine intake was replicated in rats tested on a variable ratio 5 schedule, and the 5-HT1B receptor antagonist SB 224,289 (10 mg/kg) reversed this effect. CP 94,253 also attenuated methamphetamine intake on a progressive ratio schedule both pre- and postabstinence. Similarly, zolmitriptan attenuated methamphetamine intake on a variable ratio 5 schedule both pre- and postabstinence, and the latter effect was sustained after each of 2 more treatments given every 2 to 3 days prior to daily sessions.

CONCLUSIONS

Unlike the abstinence-dependent effect of 5-HT1B receptor agonists on cocaine intake reported previously, both CP 94,253 and zolmitriptan decreased methamphetamine intake regardless of abstinence. These findings suggest that 5-HT1B receptor agonists may have clinical efficacy for psychostimulant use disorders.

Bursting deep dorsal horn neurons: the pharmacological target for the antispastic effects of zolmitriptan?

In a recent publication, Thaweerattanasinp et al. (J Neurophysiol 116: 1644-1653, 2016) investigated spinal cord injury and firing properties of deep dorsal horn neurons during NMDA or zolmitriptan application by employing electrophysiology in an in vitro spinal cord preparation. Deep dorsal horn neurons were classified into bursting, simple, or tonic firing groups,with bursting neurons showing NMDA and zolmitriptan sensitivity. We discuss the findings in a methodological framework and propose future experiments of importance for translating the results into physiological settings.

Intranasal Eutectic Powder of Zolmitriptan with Enhanced Bioavailability in the Rat Brain

Intranasal administration can potentially deliver drugs to the brain because of the proximity of the delivery site to the olfactory lobe. We prepared triturates of micronized or crystalline zolmitriptan with a GRAS substance, nicotinamide, to form a eutectic. We characterized the formulation using differential scanning calorimetry, powder X-ray diffraction, and FTIR spectroscopy to confirm its eutectic nature and generated a phase diagram. The eutectic formulation was aerosolized using an in-house insufflator into the nares of rats. Groups of rats received zolmitriptan intravenously or intranasally, or intranasal eutectic formulation. Zolmitriptan was estimated in the olfactory lobe, cerebral cortex, cerebellum, and blood plasma at different time-points by LC-MS. Pharmacokinetics in these tissues indicated the superiority of the intranasal eutectic formulation for brain targeting when compared with results of IV solution and intranasal pure zolmitriptan powder. Enhancement of nose-to-brain transport is likely to have resulted from more rapid dissolution of the eutectic as compared to pure drug.

Trans-nasal zolmitriptan novasomes: in-vitro preparation, optimization and in-vivo evaluation of brain targeting efficiency

Migraine attack is a troublesome physiological condition associated with throbbing, intense headache, in one half of the head. Zolmitriptan is a potent second-generation triptan, prescribed for patients with migraine attacks, with or without an aura, and cluster headaches. The absolute bioavailability of zolmitriptan is about 40% for oral administration; due to hepatic first metabolism. Nasal administration would circumvent the pre-systemic metabolism thus increasing the bioavailability of zolmitriptan. In addition, due to the presence of microvilli and high vasculature, the absorption is expected to be faster compared to oral route. However, the bioavailability of nasal administered drugs is particularly restricted by poor membrane penetration. Thus, the aim of this work is to explore the potential of novel nanovesicular fatty acid enriched structures (novasomes) for effective and enhanced nasal delivery of zolmitriptan and investigate their nose to brain targeting potential. Novasomes were prepared using nonionic surfactant, cholesterol in addition to a free fatty acid. A 2³ full factorial design was adopted to study the influence of the type of surfactant, type of free fatty acid and ratio between the free fatty acid and the surfactant on novasomes properties. The particle size, entrapment efficiency, polydispersity index, zeta potential and % zolmitriptan released after 2 h were selected as dependent variables. Novasomes were further optimized using Design Expert® software (version 7; Stat-Ease Inc., Minneapolis, MN), and an optimized formulation composed of Span® 80:Cholesterol:stearic acid (in the ratio 1:1:1) was selected. This formulation showed zolmitriptan entrapment of 92.94%, particle size of 149.9 nm, zeta potential of -55.57 mV, and released 48.43% zolmitriptan after 2 h. The optimized formulation was further examined using transmission electron microscope, which revealed non-aggregating multi-lamellar nanovesicles with narrow size distribution. DSC, XRD examination of the optimized formulation confirmed that the drug have been homogeneously dispersed throughout the novasomes in an amorphous state. In-vivo bio-distribution studies of ^99mTc radio-labeled intranasal zolmitriptan loaded novasomes were done on mice, the pharmacokinetic parameters were compared with those following administration of intravenous ^99mTc-zolmitriptan solution. Results revealed the great enhancement in zolmitriptan targeting to the brain, with drug targeting potential of about 99% following intranasal administration of novasomes compared with the intravenous drug solution. Zolmitriptan loaded novasomes administered via the nasal route may therefore constitute an advance in the management of acute migraine attacks.

Formulation development and evaluation of zolmitriptan oral soluble films using 22 factorial designs

Objective:

The present investigation involves the development of zolmitriptan oral soluble film (OSF) formulations and optimization with quality by design (QBD) using natural polymers and evaluation.

Materials and Methods:

Initially, various natural polymers such as sodium alginate, pectin, and gelatin were screened by casting films using solvent casting technique and the prepared films were evaluated. Based on the physical and mechanical properties, sodium alginate was selected as best film former and zolmitriptan-loaded films were casted. The formulation was optimized with the help of 2² factorial experimental designs (QBD) in which sodium alginate concentration and plasticizer concentrations were used as factors and at two levels. The drug-loaded films were evaluated for various mechanical, physicochemical properties, and in vitro drug release properties. Factor effects were interpreted by calculating the main factor effects and by plotting the interaction plots.

Results:

Thickness of the films, disintegration time, and percent drug loading efficiency were in the range of 0.698 ± 0.13–1.318 ± 0.22 mm, 175 ± 3.1–280 ± 1.7 s, and 68.34 ± 0.5–94.70 ± 0.7% w/v, respectively. Cumulative percent drug released was 61.8 ± 2.6–94.7 ± 4.1% after 30 min. Polymer concentration at two levels of plasticizer had statistically significant effect on drug loading efficiency and in vitro drug release rate. X₂ formulation was found to be excellent in drug loading efficiency and in vitro drug release profiles; hence, drug excipient compatibility studies using Fourier transform infrared spectroscopy and stability studies for 60 days were carried out for X₂ formulation and found to be stable.

Conclusion:

Sodium alginate OSFs containing zolmitriptan was successfully prepared, optimized, and evaluated.

Drug in Adhesive Patch of Zolmitriptan: Formulation and In vitro /In vivo Correlation

The objective of the present study was to develop transdermal patch for zolmitriptan, determine its in vivo absorption using the rabbit skin. Solvent evaporation technique prepared zolmitriptan patch was settled in two-chamber diffusion cell combined with excised rabbit abdomen skin for permeation study. A sufficient cumulative penetration amount of zolmitriptan (258.5 ± 26.9 μg/cm(2) in 24 h) was achieved by the formulation of 4% zolmitriptan, 10% Azone, and adhesive of DURO-TAK® 87-4098. Pharmacokinetic parameters were determined via i.v. and transdermal administrations using animal model of rabbit. The results revealed that the absolute bioavailability was about 63%. Zolmitriptan could be detected with drug level of 88 ± 51 ng/mL after transdermal administration of 15 min. The in vivo absorption curve obtained by deconvolution approach using WinNonlin® program was correlated well with the in vitro permeation curve, the correlation coefficient R is 0.84, and the result indicated that in vitro skin permeation experiments were useful to predict the in vivo performance. In addition, little skin irritation was found in the irritation study. As a conclusion, the optimized zolmitriptan transdermal patches could effectively deliver adequate drug into systemic circulation in short time without producing any irritation phenomenon and worth to be developed.

Preparation and evaluation of sublingual tablets of zolmitriptan

AIM

Zolmitriptan is a 5-HT receptor agonist (1B/1D). It is used in the acute treatment of migraine having low bioavailability about 40% orally due to hepatic first pass metabolism. The purpose of the present research was to formulate fast acting sublingual tablets of zolmitriptan.

MATERIALS AND METHODS

Sublingual tablets were prepared using ispaghula husk powder, gellan gum, sodium alginate as super disintegrating polymers and citric acid, tartaric acid and camphor as permeation enhancers by direct compressible technique and evaluated for weight variation, thickness, friability, content uniformity, hardness, disintegration time, wetting time, in-vitro drug release, in-vitro and ex-vivo permeation study. Stability study of optimized formulation was performed as per ICH (International Conference on Harmonisation) guideline.

RESULTS

The in-vitro disintegration time of the optimized formulation (D5) was 9 ± 2 s and all formulations showed 100% of dissolution within 6 ± 2 min. Formulation containing 4% of gellan gum (D5) showed highest disintegration and 2% of citric acid formulation (P3) showed highest permeation 88% within 30 min and ex-vivo permeation was 52% within 30 min. Optimized formulation was stable for 1 month during stability study as per ICH guideline.

CONCLUSION

The sublingual tablet formulation gives better results using natural super disintegrant for fast onset of action.

A new stability indicating HPLC method for related substances in zolmitriptan

A sensitive, precise, specific, linear and stability indicating isocratic HPLC method was developed for the analysis of related substances in zolmitriptan. The potential known related substances are (S)-4-(4-aminobenzyl)-1,3-oxazolidin-2-one (impurity I) and (S)-4-(4-hydrazinobenzyl)-1,3-oxazolidin-2-one (impurity II). The method can be used for the detection and quantification of known and unknown impurities and degradants in the drug substance zolmitriptan during routine analysis and also for stability studies in view of its capability to separate degradation products.

The antimigraine 5-HT 1B/1D receptor agonists, sumatriptan, zolmitriptan and dihydroergotamine, attenuate pain-related behaviour in a rat model of trigeminal neuropathic pain

1. Peripheral lesion to the trigeminal nerve may induce severe pain states. Several lines of evidence have suggested that the antimigraine effect of the triptans with 5-HT(1B/1D) receptor agonist properties may result from inhibition of nociceptive transmission in the spinal nucleus of the trigeminal nerve by these drugs. On this basis, we have assessed the potential antinociceptive effects of sumatriptan and zolmitriptan, compared to dihydroergotamine (DHE), in a rat model of trigeminal neuropathic pain. 2. Chronic constriction injury was produced by two loose ligatures of the infraorbital nerve on the right side. Responsiveness to von Frey filament stimulation of the vibrissal pad was used to evaluate allodynia. 3. Two weeks after ligatures, rats with a chronic constriction of the right infraorbital nerve displayed bilateral mechanical hyper-responsiveness to von Frey filament stimulation of the vibrissal pad with a mean threshold of 0.38+/-0.04 g on the injured side and of 0.43+/-0.04 g on the contralateral (left) side (versus > or =12.5 g on both sides in the same rats prior to nerve constriction injury). 4. Sumatriptan at a clinically relevant dose (100 microg kg(-1), s.c.) led to a significant reduction of the mechanical allodynia-like behaviour on both the injured and the contralateral sides (peak-effects 6.3+/-1.1 g and 4.4+/-0.7 g, respectively). A more pronounced effect was obtained with zolmitriptan (100 microg kg(-1), s.c.) (peak-effects: 7.4+/-0.9 g and 3.2+/-1.3 g) whereas DHE (50-100 microg kg(-1), i.v.) was less active (peak-effect approximately 1.5 g). 5. Subcutaneous pretreatment with the 5-HT(1B/1D) receptor antagonist, GR 127935 (3 mg kg(-1)), prevented the anti-allodynia-like effects of triptans and DHE. Pretreatment with the 5-HT(1A) receptor antagonist, WAY 100635 (2 mg kg(-1), s.c.), did not alter the effect of triptans but significantly enhanced that of DHE (peak effect 4.3+/-0.5 g). 6. In a rat model of peripheral neuropathic pain, which consisted of a unilateral loose constriction of the sciatic nerve, neither sumatriptan (50-300 microg kg(-1)) nor zolmitriptan (50-300 microg kg(-1)) modified the thresholds for paw withdrawal and vocalization in response to noxious mechanical stimulation. 7. These results support the rationale for exploring the clinical efficacy of brain penetrant 5-HT(1B/1D) receptor agonists as analgesics to reduce certain types of trigeminal neuropathic pain in humans.

Molecular cloning, pharmacological properties and tissue distribution of the porcine 5-HT(1B) receptor

Using a combination of RT - PCR and inverse-PCR techniques, we amplified, cloned and sequenced a full-length porcine 5-HT(1B) receptor cDNA derived from porcine cerebral cortex. Sequence analysis revealed 1170 bp encoding an open reading frame of 390 amino acids showing a 95% similarity with the human 5-HT(1B) receptor. The recombinant porcine 5-HT(1B) cDNA was expressed in monkey Cos-7 cells and its pharmacological profile was determined by radioligand binding assay using [(3)H]-GR125743. The affinities of several agonists (L694247>ergotamine > or =5-carboxamidotryptamine=dihydroergotamine=5-HT>CP122638=zolmitriptan>sumatriptan) and putative antagonists (GR127935>methiothepin>SB224289>>ritanserin>ketanserin > or =BRL15572) correlated highly with those described for the recombinant human 5-HT(1B) receptor. In membranes obtained from cells co-expressing the porcine 5-HT(1B) receptor and a mutant G(alphao)Cys(351)Ile protein, 5-HT and zolmitriptan increased, while the 5-HT(1B) receptor antagonist SB224289 decreased basal [(35)S]-GTPgammaS binding, thus showing inverse agonism. The potency of zolmitriptan in the [(35)S]-GTPgammaS binding assay (pEC(50): 7.64+/-0.04) agreed with its affinity in displacing the antagonist [(3)H]-GR125743 (pK(i): 7.36+/-0.07). The 5-HT(1B) receptor mRNA was observed by RT-PCR in several blood vessels, cerebral cortex, cerebellum and trigeminal ganglion. In situ hybridization performed in frontal cerebral cortex sections revealed the expression of 5-HT(1B) receptor mRNA in pyramidal cells. In conclusion, we have cloned and established the amino acid sequence, ligand binding profile and location of the porcine 5-HT(1B) receptor. This information may be useful in exploring the role of 5-HT(1B) receptor in pathophysiological processes relevant for novel drug discovery in diseases such as migraine.

Molecular cloning, sequence analysis and pharmacological properties of the porcine 5-HT(1D) receptor

A cDNA encoding the full-length 5-HT(1D) receptor derived from porcine cerebral cortex was amplified, cloned and sequenced, using guinea-pig 5-HT(1D) receptor coding sequence oligonucleotide primers in reverse transcription-polymerase chain reaction (RT - PCR). The 5' and 3' ends of the porcine 5-HT(1D) receptor cDNA were verified by inverse PCR. Sequence analysis of porcine 5-HT(1D) receptor cDNA revealed an open reading frame of 1134 nucleotides encoding a polypeptide of 377 amino acids having 92% homology with the human 5-HT(1D) receptor and 88 - 90% homology with other species homologues. The porcine 5-HT(1D) receptor cDNA was further subcloned into a mammalian expression vector pcDNA3 and expressed in monkey Cos-7 cells. Radioligand binding assays using either [(3)H]-5-CT or [(3)H]-GR125743 on Cos-7 cell membranes showed that pK(i) values of 14 serotonin ligands were highly correlated with those obtained with the human 5-HT(1D) receptor. Nonetheless, a selective antagonist at the human 5-HT(1D) receptor, BRL15572, only poorly recognized the porcine homologue. Using membranes from cells co-expressing the porcine 5-HT(1D) receptor and rat G(alphail)Cys(351) Ile protein, it was shown that 5-HT and zolmitriptan increased, while ketanserin decreased basal [(35)S]-GTPgammaS binding. The potency of zolmitriptan in the [(35)S]-GTPgammaS binding assay (pEC(50): 8. 46+/-0.08) agreed with its affinity in displacing the radioligands [(3)H]-5-CT and [(3)H]-GR125743 (pK(i): 8.38+/-0.15 and 8.67+/-0.08, respectively). In conclusion, we have established the cDNA sequence and pharmacology of the cloned porcine 5-HT(1D) receptor. This information would be useful in exploring the role of divergent amino acid residues in the receptor-ligand interaction as well as the role of 5-HT(1D) receptor in pathophysiological processes relevant for novel drug discovery in diseases such as migraine.

The absolute bioavailability and effect of food on the pharmacokinetics of zolmitriptan in healthy volunteers

AIMS

Zolmitriptan (Zomig (formerly 311C90)) is a novel 5-HT1B/1D receptor agonist developed for the acute oral treatment of migraine. A highly sensitive LCMS-MS assay has been developed which allows quantification of plasma concentrations of zolmitriptan and its active metabolite, 183C91, after therapeutic doses. Two studies using this assay method were conducted to investigate the pharmacokinetics, including absolute bioavailability, of 2.5 and 5 mg oral doses of zolmitriptan in men and women, the dose-proportionality of 2.5, 5 and 10 mg doses and the effect of food on the pharmacokinetics of a 5 mg oral dose.

METHODS

Two randomized, balanced, open-label, 4-period crossover studies were conducted in a total of 32 healthy volunteers. The first study determined the absolute bioavailability of 2.5 and 5 mg doses of zolmitriptan and compared the pharmacokinetics in men and women. The second study examined the dose-proportionality in pharmacokinetics after fasting doses of 2.5, 5 and 10 mg, and the effect of food on a 5 mg dose. Blood pressure, heart rate, ECG, clinical chemistry, haematology and adverse events were also monitored.

RESULTS

The mean (s.d.) absolute oral bioavailability was 0.41 (0.14 and 0.40) 0.09 after 2.5 mg and 0.48+/-0.14 and 0.36+/-0.07 after 5 mg in women and men, respectively. Without adjustment for bodyweight, plasma concentrations of zolmitriptan, but not 183C91, were higher in women than men. Mean (+/-s.d.) AUC was 32.7+/-10.1 and 60.2+/-26.8 ng ml(-1) h after 5 mg in men and women, respectively (95% CI for ratio 0.43-0.77). After 2.5 mg mean (+/-s.d.) AUC was 18.4+/-5.4 and 23.1+/-9.9 ng ml(-1) h in men and women, respectively (95% CI for ratio 0.61-1.09). However, these differences were of no clinical significance. Cmax and AUC of oral zolmitriptan were dose-proportional and there was a 13 and 16% fall in mean zolmitriptan Cmax and AUC, respectively, when administered after food. Adverse effects were minor, predominantly mild and transient, and there were no clinically significant effects on ECG, blood pressure, or laboratory parameters.

CONCLUSIONS

At therapeutic doses zolmitriptan has good oral bioavailability in healthy volunteers and has dose-proportional pharmacokinetics that are not affected by food to any clinically relevant extent.

Pharmacological analysis of the haemodynamic effects of 5-HT1B/D receptor agonists in the normotensive rat

1 The receptors involved in mediating the haemodynamic effects of three 5-HT1B/D receptor agonists were investigated in pentobarbitone anaesthetized rats (n = 6-17 per group). 2 Cumulative intravenous (i.v.) infusions of rizatriptan and sumatriptan (from 0.63 to 2500 microg kg(-1); each dose over 5 min) induced dose-dependent and marked hypotension (-42+/-6 and -34+/-4 mmHg at the highest dose, respectively; both P<0.05 vs vehicle: +5+/-3 mmHg) and bradycardia (-85+/-16 and -44+/-12 beats min(-1) at the highest dose, respectively; both P<0.05 vs vehicle: +16+/-6 beats min(-1)). Zolmitriptan evoked only moderate hypotension at the highest dose (-19+/-9 mmHg; P<0.05 vs vehicle). 3 A high dose of the 5-HT1B/D receptor antagonist, GR 127935 (0.63 mg kg(-1), i.v.), failed to antagonize the hypotension and bradycardia evoked by sumatriptan (-35+/-6 mmHg and -52+/-19 beats min(-1), respectively; both not significant vs sumatriptan in untreated rats), but moderately reduced the hypotension and bradycardia evoked by rizatriptan (-20+/-5 mmHg and -30+/-17 beats min(-1), respectively; both P<0.05 vs vehicle and vs rizatriptan in untreated rats). 4 The selective 5-HT1A receptor antagonist, WAY 100635 (0.16 and 0.63 mg kg(-1), i.v.), dose-dependently attenuated the haemodynamic responses evoked by rizatriptan and sumatriptan, which were almost abolished by the higher dose of WAY 100635 (-4+/-3 mmHg and -15+/-8 beats min(-1); both not significant vs vehicle and P<0.05 vs rizatriptan in untreated rats). A slight but statistically significant reduction in mean arterial pressure (MAP) persisted at the highest dose of sumatriptan (-13+/-4 mmHg following the higher dose of WAY 100635; P<0.05 vs vehicle). 5 In pithed rats with MAP normalized by angiotensin II, rizatriptan failed to induce hypotension or bradycardia (+5+/-4 mmHg and -6+/-16 beats min(-1), respectively; both NS vs vehicle and P<0.05 vs rizatriptan in untreated rats). Similarly, sumatriptan failed to induce bradycardia in pithed rats (+5+/-6 beats min(-1); not significant vs vehicle and P<0.05 vs sumatriptan in untreated rats), whereas a slight but statistically significant reduction in MAP, compared to controls, occurred at the highest dose (-9+/-9 mmHg; P<0.05 vs both vehicle and sumatriptan in untreated rats). 6 In bilaterally vagotomized and atropine-treated (1 mg kg(-1), i.v.) rats, the reductions in MAP and heart rate evoked by rizatriptan (-31+/-4 mmHg and -64+/-9 beats min(-1), respectively; both P<0.05 vs vehicle and not significant vs rizatriptan in controls) and sumatriptan (-47+/-8 mmHg and -56+/-10 beats min(-1), respectively; both P<0.05 vs vehicle and not significant vs sumatriptan in controls) were not statistically significantly different from those observed in controls. 7 In conclusion, the 5-HT1B/D receptor agonists, rizatriptan and sumatriptan, elicit hypotension and bradycardia in the normotensive anaesthetized rat predominantly via activation of central 5-HT1A receptors, and a consequent reduction in sympathetic outflow.

The interaction between propranolol and the novel antimigraine agent zolmitriptan (311C90)

AIMS

Zolmitriptan (Zomig, formerly known as 311C90), a selective 5HT1B/1D agonist is under development as an acute oral treatment for migraine. Despite the use of prophylactic medication, such as propranolol, breakthrough attacks often occur in patients. Consequently we investigated the effects of propranolol on the pharmacokinetics of, and cardiovascular responses to, zolmitriptan.

METHODS

A double-blind, randomized, crossover study of the effects of pre-treatment with propranolol 160 mg daily for 7 days or placebo on the pharmacokinetics and effects on blood pressure of a single 10 mg dose of zolmitriptan in 12 healthy volunteers.

RESULTS

Propranolol increased mean zolmitriptan Cmax and AUC by 56% and 37% respectively; mean t1/2 was prolonged from 3.1 to 4.0 h. Mean Cmax and AUC of the pharmacologically active N-desmethyl metabolite were reduced by 24% and 11% respectively and the metabolite:parent AUC ratio (AUCm/AUCp) fell from 0.46 to 0.26. Mean Cmax and AUC for the inactive indole acetic acid metabolite were both reduced by 13% and AUCm/AUCp from 1.04 to 0.59. A small pressor effect of short duration was observed following zolmitriptan with mean peak rises of 13 and 11 mmHg in systolic and diastolic pressures respectively; propranolol had no effect on the pressor response.

CONCLUSIONS

The results suggest that propranolol inhibits biotransformation of zolmitriptan but with no change in the small pressor response to zolmitriptan. It is therefore unlikely that the pharmacokinetic changes will lead to clinically important changes in pharmacological effects and dosage adjustment of zolmitriptan is not required in patients taking propranolol for migraine prophylaxis.

The absolute bioavailability and metabolic disposition of the novel antimigraine compound zolmitriptan (311C90)

AIMS

Two open studies in healthy volunteers were conducted to determine the absolute bioavailability and metabolic disposition of zolmitriptan (311C90), a novel 5HT1D agonist for the acute treatment of migraine.

METHODS

After an initial test i.v. infusion, bioavailability was assessed by comparison of AUC after an i.v. infusion (3.5 mg) and an oral tablet (10 mg), in six men and six women using a randomised, crossover design. Disposition was studied by administration of a 25 mg capsule, labelled with 100 microCi [14C]-zolmitriptan, to five men and one woman on a single occasion.

RESULTS

Zolmitriptan was well tolerated by both i.v. and oral routes. Adverse events were mostly mild, consistent with earlier studies and characteristic of this class of drug. Reports were similar in nature and number after both oral and i.v. dosing. Mean +/- s.d. oral bioavailability was 0.49 +/- 0.24 (0.38 +/- 0.16 in men and 0.60 +/- 0.28 in women). After oral dosing, Cmax and AUC values in women were approximately double those in men. Relative to zolmitriptan concentrations, metabolite concentrations were higher after oral dosing than after i.v., and higher in men compared with women. Half-life was significantly longer after oral dosing (mean 22%, 95% CI 6-35%). Mean +/- s.d. values for CL, V2 and t1/2,z after i.v. dosing (all subjects) were 8.7 +/- 1.7 ml min-1 kg-1, 122 +/- 321 and 2.30 +/- 0.59 h respectively. Following administration of 25 mg [14C]-zolmitriptan, 91.5% of the dose was recovered in 7 days, 64.4 +/- 6.5% in urine and 27.1 +/- 6.0% in faeces. Less than 10% was recovered unchanged in urine, with 31.1 +/- 6.4% recovered as the inactive indole acetic acid metabolite. Most of the faecal material was unchanged zolmitriptan, representing unabsorbed drug. Plasma concentrations of [14C] were slightly higher than those of the summed concentrations of known analytes zolmitriptan, the active N-desmethyl metabolite (183C91), the inactive N-oxide (1652W92) and indole acetic acid (2161W92) metabolites, which accounted for 86% of total plasma radioactivity. No other significant metabolites were detected in plasma. Some minor additional metabolites were detected in urine, none of which contributed more than 5% of the dose.

CONCLUSIONS

The data suggest that zolmitriptan undergoes first-pass metabolism and this is more extensive in men than in women. Zolmitriptan has suitable bioavailability for an acute oral migraine treatment and there are no significant unidentified metabolites in man.

The pharmacokinetics and effects on blood pressure of multiple doses of the novel anti-migraine drug zolmitriptan (311C90) in healthy volunteers

AIMS

Zolmitriptan (311C90), a novel, selective, centrally and peripherally acting 5-HT1D-receptor agonist is under development as an acute treatment for migraine. The tolerability, pharmacokinetics and effects on blood pressure and heart rate of multiple doses of 5 or 10 mg (5 doses administered over 24 h) were compared, in healthy adult volunteers, with those after placebo and single doses of zolmitriptan.

METHODS

Twelve subjects participated in a randomized, balanced, crossover comparison. Plasma and urine concentrations of zolmitriptan and its metabolites, pulse rate and blood pressure were measured at intervals after drug. Ten volunteers completed the study.

RESULTS

Zolmitriptan was well tolerated after single and multiple doses throughout the study. There was no evidence of significant changes in the pharmacokinetic parameters of zomitriptan or its metabolites after the last dose compared to the first, except for an expected rise in peak concentrations and a small, apparent increase in the amount of drug excreted in urine and hence in CLR. After the last 10 mg dose, mean dosing interval zolmitriptan AUC was 80.3 ng ml-1 h compared with 86.5 ng ml-1 h after the single 10 mg dose (95% CI for ratio 0.76-1.13). There was no evidence of changes in the pharmacokinetic parameters of zolmitriptan and its metabolites after 10 mg compared with 5 mg, except a small increase in zolmitriptan CLR. There were no statistically significant increases in peak systolic or diastolic blood pressure after the last doses of zolmitriptan compared to placebo or in peak blood pressure after the last dose compared to the first. There were no significant differences between blood pressure immediately before the first and last doses of each multiple dose regimen. Peak erect systolic blood pressure after the last 10 mg dose (137 mmHg) was significantly lower than that after placebo (147 mmHg, 95% CI for difference -18, -2) and that after the last 5 mg dose (148 mmHg, 95% CI -19, -3).

CONCLUSIONS

Repeated doses of 5 or 10 mg zolmitriptan are well tolerated despite higher plasma concentrations than expected from single doses.