The pharmacokinetics of the antimigraine compound zolmitriptan in Japanese and Caucasian subjects

BACKGROUND: Zolmitriptan is a 5HT(1B/1D) receptor agonist effective in the acute treatment of migraine. Clinical trials in the USA and Europe have demonstrated the optimal oral therapeutic dose to be 2.5 mg. The 2.5-mg oral tablet has recently been licensed in Japan. OBJECTIVE: To compare the pharmacokinetics of zolmitriptan and its metabolites in Japanese and Caucasian subjects and evaluate the effect of gender on these pharmacokinetics in Japanese volunteers. METHODS: In this open, parallel-group study, 30 Japanese and 30 Caucasian volunteers (20-45 years) received a single 2.5-mg zolmitriptan tablet in the fasting state. Blood samples were taken up to 15 h post-dose to determine plasma concentrations of zolmitriptan and its active metabolite, 183C91. Urinary excretion of zolmitriptan, 183C91 and the inactive N-oxide and indole acetic acid metabolites were measured over 24 h. RESULTS: Japanese volunteers were, on average, smaller and lighter than Caucasian volunteers. Plasma-concentration profiles of zolmitriptan and 183C91 were similar in the two groups. Although geometric mean zolmitriptan and 183C91 area under the plasma concentration-time curve (AUC) and maximum plasma concentration (C(max)) were slightly higher in Japanese subjects (up to 20%), these differences were not considered to be of clinical relevance as the 90% confidence interval for the ratio of AUCs fell within pre-specified limits (0.67 to 1.5). Mean zolmitriptan and 183C91 half-lives were around 2.5 h for both populations. Urinary excretion of the four analytes was similar in Japanese and Caucasians. Plasma concentrations of zolmitriptan were higher in Japanese females than males (AUC 40% and C(max) 29% higher), consistent with the results previously obtained in Caucasians. CONCLUSION: Pharmacokinetic parameters of zolmitriptan were similar between Caucasian and Japanese volunteers.     

Pharmacokinetics,dose proportionality,and tolerability of single and repeat doses of a nasal spray formulation of zolmitriptan in healthy volunteers

The objective of this study was to investigate the pharmacokinetics, dose proportionality, and tolerability of a range of single and multiple doses of a nasal spray formulation of zolmitriptan in a randomized, double-blind, placebo-controlled, balanced, incomplete crossover study. Thirty healthy male or female volunteers received two of five dose levels of zolmitriptan nasal spray: 0 (placebo), 0.5, 1, 2.5, and 5 mg. At each level, treatment comprised a single dose on day 1 and two doses (separated by 2 h) on each of days 2, 3, and 4. Zolmitriptan was well tolerated, and symptoms were generally mild and of short duration. The most commonly reported adverse events were taste disturbance, paresthesia, hyperesthesia, headache, and nasal/throat discomfort. Volunteers generally reported fewer adverse events during the multiple-dose phase than after the single-dose phase. Zolmitriptan was detectable in plasma within 15 minutes, and t(max) was similar for each dose and after single and multiple dosing. Dose proportionality was shown for the C(max) and AUC of both zolmitriptan and its active metabolite, 183C91. Mean t1/2 for zolmitriptan and 183C91 was approximately 3 hours. It was concluded that the pharmacokinetics (C(max) and AUC) for both zolmitriptan and 183C91 was proportional to dose after both single and multiple dosing. Nasal spray zolmitriptan was well tolerated; the frequency and nature of adverse events did not increase after multiple dosing.     

Intranasal absorption of rizatriptan--in vivo pharmacokinetics and bioavailability study in humans

Rizatriptan nasal spray was developed to achieve fast a high effectiveness and to overcome limitations associated with oral formulation. The objective of this study was to investigate the pharmacokinetics and tolerability of a rizatriptan nasal spray compared with an oral formulation in a two treatments, two periods, randomized crossover design. At each phase, each subject received 5 mg rizatriptan as a nasal spray or an oral tablet. Plasma concentrations of rizatriptan were determined by HPLC. Rizatriptan was absorbed more rapidly following nasal spray with detectable plasma concentrations 5 min after dosing. There was no statistically significant difference for AUC or Cmax values between the nasal spray and the oral tablet. The relative bioavailability of nasal formulation to oral formulation was 96%+/-16%. All the formulations were well tolerated and adverse events were generally of short duration and of mild intensity. Thus, rizatriptan nasal spray offers more rapidly absorption compared to the oral route, which may be particularly beneficial to those patients who have gastrointestinal disturbances during their migraine attack or who have difficulty in swallowing a tablet.     

True nasopharyngeal absorption of zolmitriptan after administration via nasal spray in healthy male volunteers

Objective

The aim of this study was to quantify the fraction of zolmitriptan that is absorbed directly through the nasal mucosa after administration of zolmitriptan nasal spray.

Methods

Following confirmation that activated charcoal blocks gastrointestinal absorption of zolmitriptan, healthy male volunteers were given zolmitriptan nasal spray 5mg (with and without charcoal) and zolmitriptan 5mg oral tablets (with and without charcoal) in a randomized, crossover design. Blood samples for pharmacokinetic analysis were collected up to 9 hours post-dose. Twelve subjects completed all treatments.

Results

The fraction of bioavailable dose absorbed through the nasal mucosa was calculated to be 29% (95% CI 19, 43). Intranasal absorption contributed 71% of zolmitriptan exposure during the first hour post-dose and 49% during the first 2 hours.

Conclusions

This study confirms true nasopharyngeal absorption of zolmitriptan after nasal spray administration. This route of absorption contributed approximately 30% of total zolmitriptan exposure, with much higher proportions of exposure seen during the first 2 hours post-dose when patients would expect to benefit from treatment. These results suggest that intranasal absorption plays an important role in the early onset of efficacy of zolmitriptan nasal spray seen in clinical trials.     

佐米曲普坦鼻喷雾剂与其片剂之间的相对生物利用度

目的研究国产佐米曲普坦鼻喷雾剂的人体药动学特性及与其口服制剂之间的相对生物利用度。方法采用双周期、开放、随机的自身交叉设计,20例健康志愿者分别单次121服参比制剂或鼻喷受试制剂各5mg,用液相色谱串联质谱法测定血浆中佐米曲普坦的浓度,并采用DAS程序对试验数据进行处理,求算有关药动学参数和相对生物利用度。结果佐米曲普坦鼻喷雾剂和片剂的主要药动学参数：pmax分别为（10．44±3．59）、（12．164±2．85）μg·L-1,tmax分别为（3．18±1．32）、（2．21±1．26）h,t1／2分别为（2．27±0．43）、（2．34±0．46）h,AucPl5h分别为（66．64±24．17）、（74．09±21．749）μg·h·L-1,AUC0→∞分别为（68．02±24．59）、（76．02±22．68）μg·h·L-1;以Aucp‰计,单次鼻喷受试制剂的相对生物利用度为（89．47±17．03）％。单次给药后两者的Pmax、AUC0→5h、AUC0→∞经对数转换后双单侧t检验,均在其等效标准范围内。tmax经Wilcoxon检验,差异有统计学意义,鼻喷雾剂比口服制剂达峰时间明显延后,但在给药后0．5h内其吸收比口服制剂快。结论国产佐米曲普坦鼻喷剂相对于参比制剂具有生物等效性,同时具有吸收快,临床上可达到快速起效的优点。     

The metabolism of zolmitriptan: effects of an inducer and an inhibitor of cytochrome p450 on its pharmacokinetics in healthy volunteers

Two studies were conducted in healthy volunteers to evaluate the effects of rifampicin and cimetidine on the pharmacokinetics of the oral antimigraine compound zolmitriptan. Each study was an open, randomised, two-period crossover design. Rifampicin 600mg was administered daily for 8 days and cimetidine 400mg was administered three times daily for 2 days. In the control periods, no treatment was given. A single 5mg oral dose of zolmitriptan was given on the last day of each period. Enzyme induction by rifampicin was monitored using 6-beta hydroxycortisol/cortisol ratios. Rifampicin resulted in small (<18%), clinically insignificant decreases in the mean area under the plasma concentration-time curve (AUC), maximum plasma concentration (C(max)) and elimination half-life (t((1/2))) of zolmitriptan and its active metabolite, 183C91. Cimetidine, however, inhibited the metabolism of zolmitriptan and 183C91, increasing the mean C(max) by 16 and 50%, respectively, and increasing the mean AUC by 48 and 105%, respectively. Mean t((1/2)) was prolonged by 2.2 hours for zolmitriptan and by 4.2 hours for 183C91. The tolerability of zolmitriptan was unaltered when it was administered with either drug. Cytochrome 1A2 is likely to be the isoenzyme responsible for the metabolism of zolmitriptan. The increased exposure to zolmitriptan and 183C91 by cimetidine indicated that a reduction in the total daily recommended dose of zolmitriptan may be necessary when treating migraine patients who are taking nonspecific cytochrome P450 inhibitors or specific cytochrome 1A2 inhibitors.     

The bioavailability of ofloxacin from several formulations

The bioavailability of ofloxacin after a single dose of one of two tablet formulations (200 or 400 mg) or a liquid formulation (1.67 mg/ml) was investigated in 24 healthy male volunteers in an open randomized, crossover design study with a 5-day wash-out period between doses. Plasma concentrations of ofloxacin were determined at various times after administration by a sensitive and specific High Pressure Liquid Chromatography (HPLC) method. Ofloxacin was well absorbed after each administration, although somewhat more slowly after the tablet formulations than the solution. Mean AUC values of 31.8, 31.3, and 31.3 micrograms.hr/ml were calculated after administration of the solution, 2 x 200 mg tablets and a 400 mg tablet, respectively. Thus, the bioavailability of the tablets was in excess of 98% that of the liquid reference. Mean Cmax values of 4.4, 3.7 and 3.7 micrograms/ml were observed at Tmax values of 0.8, 1.6 and 1.8 hours after administration of the solution, 2 x 200 mg tablets and a 400 mg tablet, respectively. The drug was well tolerated and no adverse effects necessitating subject withdrawal were noted during the study.     

Bioavailability of atenolol formulations

In this comparative bioavailability study two tablet formulations of atenolol (sales and clinical trial) were compared with an oral solution. Twelve healthy adult male volunteers received, on a cross-over basis, on three separate occasions, 100 mg oral dose of the three formulations of atenolol. Bioavailability was based on concentrations of atenolol in whole blood and urine. The atenolol blood levels peaked at approximately 3 h after dosing, with individual values ranging from 0·21 to 0·92 μg ml^?1 (a four-fold difference), with all three formulations. Three-fold variations among subjects occurred in the areas under the curve (AUC) and urinary recoveries. The average elimination half-life of atenolol was between 6 and 7 h for all three formulations. Some statistically significant differences were observed between the tablets and the aqueous solution: the AUC (∞) and mean peak blood concentrations were significantly greater with the U.K. sales tablet than the solution, and the mean concentrations in the blood at certain specified times after administration were significantly greater with the two tablet formulations than the solution. The profiles of absorption and excretion of the two tablet formulations were similar. No adverse reactions were encountered in this study and all subjects completed the study without incident.     

Systemic bioavailability of nasally applied chlorphenamine maleate (0.4% nasal spray) relative to tablets administered perorally

AIM: This study investigated the bioavailability of single doses of 1.12 and 2.24 mg chlorphenamine maleate applied intranasally (0.4% nasal spray) relative to a single peroral dose of 8 mg chlorphenamine maleate (tablets). METHODS: Twenty-four (24) subjects were treated with single nasal doses of 1.12 mg and 2.24 mg chlorphenamine maleate (0.4% nasal spray) and two 4 mg chlorphenamine maleate tablets (Piriton) on 3 separate study days according to a 3-way cross-over design with a 7-day wash-out between periods. Blood was sampled before and at 0.25, 0.50, 1.0, 2.0, 3.0, 4.0, 6.0, 8.0, 12, 16 and 24 hours after drug administration. Additional blood samples were obtained 36, 48 and 72 hours after peroral administration only. All subjects were included in the pharmacokinetic analysis. RESULTS: Nasally applied chlorphenamine maleate was readily absorbed, reaching peak plasma levels after 0.25 to 3.0 hours. The dose-normalized estimated mean Cmax values were 1.24, 1.43 and 1.21 ng/ml for the peroral tablet and the 1.12 mg and 2.24 mg nasal dose, respectively. The dose-normalized estimated mean AUC(0-infinity) values were 25.91, 26.44 and 25.56 ng x h/ml for the tablet and the 1.12 and 2.24 mg nasal dose, respectively. The estimated treatment ratios (nasal dose to tablet) of the dose-normalized values for the 1.12 mg nasal dose were 1.15 (900 CI: 1.0-1.32) and 1.02 (90% CI: 0.88-1.18) for Cmax and AUC(0-infinity), respectively, for the 2.24 mg nasal dose they were 0.98 (90% CI: 0.85-1.13) and 0.99 (90% CI: 0.85-1.13) for Cmax and AUC(0-infinity), respectively. The other pharmacokinetic characteristics (tmax, t(1/2), lambda(z), AUC(0-tf), MRTtot, CL/f and Vz/f) were comparable across all treatments. These data indicate that the disposition of chlorphenamine maleate was independent of the route and dose of administration. CONCLUSIONS: Chlorphenamine maleate is readily absorbed after nasal application using a 0.4% nasal spray. The nasal administration showed that the systemic bioavailability at the two dose levels used was comparable to that for the tablet. Maximum concentrations on the low dose, however, were higher and those on the high dose were comparable to those for the tablet. The nasal application of chlorphenamine maleate does not alter the overall systemic exposure compared to the oral route.     

Blood–Brain Barrier Penetration of Zolmitriptan—Modelling of Positron Emission Tomography Data

Positron emissiontomography (PET) with the drug radiolabelled allows a direct measurement of brain or other organ kinetics, information which can be essential in drug development. Usually, however, a PET-tracer is administered intravenously (i.v.), whereas the therapeutic drug is mostly given orally or by a different route to the PET-tracer. In such cases, a recalculation is needed to make the PET data representative for the alternative administration route. To investigate the blood–brain barrier penetration of a drug (zolmitriptan) using dynamic PET and by PK modelling quantify the brain concentration of the drug after the nasal administration of a therapeutic dose. [¹¹C]Zolmitriptan at tracer dose was administered as a short i.v. infusion and the brain tissue and venous blood kinetics of [¹¹C]zolmitriptan was measured by PET in 7 healthy volunteers. One PET study was performed before and one 30 min after the administration of 5 mg zolmitriptan as nasal spray. At each of the instances, the brain radioactivity concentration after subtraction of the vascular component was determined up to 90 min after administration and compared to venous plasma radioactivity concentration after correction for radiolabelled metabolites. Convolution methods were used to describe the relationship between arterial and venous tracer concentrations, respectively between brain and arterial tracer concentration. Finally, the impulse response functions derived from the PET studies were applied on plasma PK data to estimate the brain zolmitriptan concentration after a nasal administration of a therapeutic dose. The studies shows that the PET data on brain kinetics could well be described as the convolution of venous tracer kinetics with an impulse response including terms for arterial-to-venous plasma and arterial-to-brain impulse responses. Application of the PET derived impulse responses on the plasma PK from nasal administration demonstrated that brain PK of zolmitriptan increased with time, achieving about 0.5 mg/ml at 30 min and close to a maximum of 1.5 mg/ml after 2 hr. A significant brain concentration was observed already after 5 min. The data support the notation of a rapid brain availability of zolmitriptan after nasal administration     

Speed of onset, efficacy and tolerability of zolmitriptan nasal spray in the acute treatment of migraine: a randomised, double-blind, placebo-controlled study

INTRODUCTION: Migraine is a common, disabling condition that has a significant impact on patients and relatives, and is a considerable economic burden on society. Migraine patients want fast-acting treatments with high efficacy. Previous studies have demonstrated that orally administered formulations of zolmitriptan are rapidly and highly effective in the acute treatment of migraine. The objective of this study was to assess the efficacy, speed of onset and tolerability of the nasal spray formulation of zolmitriptan in migraine treatment. METHODS: This multicentre, randomised, double-blind study recruited 2122 patients (aged 18-65 years) who had an established diagnosis of migraine (according to International Headache Society criteria), with or without aura. Patients were randomised to receive zolmitriptan 5mg nasal spray or placebo to treat up to two migraine attacks within 15 minutes of headache pain becoming moderate or severe. The primary endpoint was headache response (reduction in migraine pain from severe/moderate to mild/none) at 2 hours, 1 hour, 30 minutes and 15 minutes post-dose (analysed using a step-down approach). Secondary endpoints included headache response at 4 hours, pain-free rates at 30 minutes and 1, 2 and 4 hours, and sustained headache response and pain-free status at 24 hours post-dose. RESULTS: The headache response rate at 2 hours post-dose was 66.2% for the zolmitriptan group, compared with 35.0% for the placebo group (p < 0.001). Zolmitriptan nasal spray also produced significantly higher headache response rates than placebo at all earlier timepoints assessed, starting as early as 15 minutes post-dose (p < 0.001). Similar results were obtained for the analysis of the first attack. Significantly higher pain-free rates were obtained with zolmitriptan nasal spray, compared with placebo, from 15 minutes post-dose onward (p < 0.005). Zolmitriptan nasal spray was also significantly superior to placebo for headache response at 4 hours, sustained headache response at 24 hours and sustained pain-free rate at 24 hours.Zolmitriptan nasal spray was well tolerated, with most adverse events being of short duration and mild or moderate intensity. CONCLUSIONS: Zolmitriptan nasal spray is highly effective in the acute treatment of migraine and has a very fast onset of action, producing significant headache response and pain-free rates as early as 15 minutes post-dose (the earliest assessment in this study). In addition to the very fast onset of action, zolmitriptan nasal spray produced significantly higher sustained headache response and pain-free rates at 24 hours post-dose compared with placebo. These desirable efficacy outcomes were combined with good tolerability.     

The novel anti-migraine compound zolmitriptan (Zomig 311C90) has no clinically significant interactions with paracetamol or metoclopramide

Objective: This study investigated potential pharmacokinetic or pharmacodynamic interactions between the novel anti-migraine compound zolmitriptan (Zomig, formerly 311C90) and paracetamol and/or metoclopramide. Methods: In an open-label, randomised, crossover study, 15 healthy volunteers received single oral doses of 10 mg zolmitriptan alone, 1 g paracetamol alone, 10 mg zolmitriptan + 1 g paracetamol, 10 mg zolmitriptan + 10 mg metoclopramide or 10 mg zolmitriptan + 1 g paracetamol + 10 mg metoclopramide on five separate occasions. Results: Metoclopramide had no significant effects on the pharmacokinetics of zolmitriptan or the active zolmitriptan metabolite 183C91, nor did it affect interactions between zolmitriptan and paracetamol. Paracetamol marginally increased the maximum plasma concentration (C_max) (11%) and the area under the curve (AUC) (11%) and reduced the renal clearance of zolmitriptan (9%); similar small effects were seen on 183C91. The AUC, C_max and half-life of paracetamol were reduced by concomitant zolmitriptan (by 11%, 31% and 8%, respectively), whilst the mean residence time showed a small increase (+0.7 h). There was a trend towards a transient increase in blood pressure following all regimens containing zolmitriptan; this effect was small, was consistent between all zolmitriptan regimens as well as with previous studies, and was considered to be clinically insignificant. Zolmitriptan was well tolerated after all treatment regimens. Conclusion: Concomitant administration of zolmitriptan and paracetamol resulted in a slight increase in bioavailability of zolmitriptan and a reduced rate and extent of paracetamol absorption. These findings are considered to be of no clinical significance and there is no reason to avoid concomitant administration of paracetamol and/or metoclopramide with zolmitriptan. Received: 9 April 1997 / Accepted in revised form: 24 July 1997     

2种佐米曲普坦制剂人体生物等效性研究

目的:比较国产佐米曲普坦胶囊与进口佐米曲普坦片剂的人体生物等效性。方法:18名志愿者随机交叉单次口服佐米曲普坦胶囊或片剂10mg后,采用高效液相色谱法测定血药浓度,用3p97软件包计算二者的药动学参数和生物等效性。结果:胶囊与片剂的药-时曲线均为口服吸收一室摸型。t1/2ke分别为(3.72±1.77)、(3.81±1.44)h,tmax分别为(1.42±0.35)、(1.33±0.51)h,Cmax分别为(21.68±8.67)、(21.86±10.38)μg/L,AUC(0～T)分别为(75.94±31.34)、(78.40±28.21)(μg.h)/L。佐米曲普坦胶囊的相对生物利用度为(96.86±13.36)%,经方差分析、双单侧t检验及(1～2α)置信区间法统计分析,2种制剂药动学参数无显著性差异(P>0.05)。结论:佐米曲普坦胶囊与片剂具有生物等效性。     

Bioavailability and pharmacokinetics of oral ofloxacin formulations in normal subjects.

The relative bioavailability and pharmacokinetics of ofloxacin tablets and a reference oral solution of ofloxacin were compared in 32 normal male subjects using a randomized two-way crossover design. After an overnight fast, subjects were randomized to receive a single 200 mg or 300 mg dose of ofloxacin (tablet or solution) and blood samples were obtained prior to and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 16, 24, 36, 48, 72, 96, and 120 hours after the dose. After a 5-day wash-out period, subjects were administered the same dose but of the other formulation, and blood samples were collected in an identical manner. Plasma concentrations of ofloxacin were determined by high-pressure liquid chromatography. The results showed that ofloxacin tablets were more slowly absorbed when compared to the solution and mean peak plasma concentrations were obtained in about 1.5 hours for the tablet preparation. Maximum plasma concentrations were higher after administration of the solution (Cmax = 2.24 micrograms/ml, 200 mg; Cmax = 3.25 micrograms/ml, 300 mg) compared to the tablet (Cmax = 1.74 micrograms/ml, 200 mg; 2.61 micrograms/ml, 300 mg). The bioavailability of ofloxacin tablets was greater than 98% compared to the solution. The other pharmacokinetic parameters were similar between the two dosage formulations. Ofloxacin tablets revealed an apparent volume of distribution of 1.5 l/kg, an elimination half-life of 5.6 hours, and a total clearance of 251 ml/min. In addition, a linear increase in plasma concentrations was observed when the dose of ofloxacin was increased. In summary, ofloxacin tablets was found to be reliably bioavailable and bioequivalent to the reference solution.     

The disposition and bioavailability of intravenous and oral nalbuphine in healthy volunteers

The pharmacokinetics of intravenous and oral nalbuphine were studied in 24 healthy male volunteers ranging in age from 21 to 30 years. On separate test days over a five-week period, subjects received single doses of each of four different formulations of nalbuphine, with a one-week washout period between treatments: 10 mg intravenously administered over two minutes, 45 mg orally given as a solution, and 45 mg orally administered in two tablet formulations (formulation A and formulation B). Blood samples were collected over 48 hours postadministration, and plasma nalbuphine concentrations were determined by reversed-phase high-performance liquid chromatography (HPLC) with electrochemical detection. The mean nalbuphine plasma concentration five minutes after 10 mg intravenously was 53 ng/mL, and the half-life of nalbuphine with this route of administration was 2.3 hours. In contrast, mean maximum nalbuphine concentrations (Cmax) after the three orally administered preparations ranged from 14.4 to 15.5 ng/mL, and occurred 0.9 to 1.2 hours after dose administration. Mean elimination half-lives after administration of the three nalbuphine oral formulations were essentially identical, ranging from 6.9 to 7.7 hours. Nalbuphine plasma concentration curves decayed biexponentially regardless of route of administration or type of formulation. Absolute bioavailability of the orally administered forms of nalbuphine ranged from 16.4 to 17.4% and Cmax and AUC data further established the bioequivalence of the three oral formulations. The low absolute bioavailability and prolonged elimination half-life of nalbuphine associated with oral administration are likely due to extensive first-pass metabolism and enterohepatic circulation, respectively.     

Review of zolmitriptan and its clinical applications in migraine

Preclinical studies have shown that zolmitriptan is a selective serotonin 5-HT(1B/1D) receptor agonist (triptan). Randomised, placebo-controlled, double-blind trials in patients with migraine have shown that zolmitriptan has good efficacy measured using 2 h response and pain-free rates. Migraine-associated symptoms, including nausea, photophobia and phonophobia, are also improved with zolmitriptan. Oral zolmitriptan (2.5 and 5 mg) has an onset of action within 45 min and efficacy is sustained in most patients who respond at 2 h. The orally-disintegrating zolmitriptan tablet has the advantage that it may be taken immediately, without the need for additional fluids, any time a migraine headache occurs. Patients may benefit in terms of improved efficacy from the convenience of the disintegrating tablet, since there is evidence that taking triptan therapy as early as possible in an attack is advantageous. For similar reasons, as well as improved efficacy, a nasal spray formulation is in development. Zolmitriptan is effective in the treatment of migraine associated with menses and migraine with aura. There is no tachyphylaxis following repeated doses for multiple attacks of migraine over a prolonged period of time. Compared to placebo, the incidence of persistent migraine headache is reduced by zolmitriptan and recurrent migraine headache occurs less frequently. Zolmitriptan has also shown efficacy in the treatment of persistent and/or recurrent migraine headache. Comparative clinical studies have shown overall that zolmitriptan has similar or superior efficacy to sumatriptan in the treatment of migraine. Specifically, zolmitriptan 2.5 mg was significantly more effective than sumatriptan 25 or 50 mg according to a number of end points, including headache response at 2 h. Oral zolmitriptan is also effective in the acute treatment of cluster headache. Zolmitriptan is generally well tolerated, with most adverse events being mild-to-moderate, transient and resolving without intervention or the need for treatment withdrawal. The consistent efficacy in treating all types of migraine and the choice of available formulations make zolmitriptan acceptable to patients and a suitable first-line therapy for the treatment of migraine.     

Comparison of plasma and saliva concentrations of levetiracetam following administration orally as a tablet and as a solution in healthy adult volunteers

OBJECTIVE: Concentrations in saliva, as an alternative to concentrations in blood, can be advantageous for the monitoring of antiepileptic agents. This study assesses the relationship between saliva and plasma concentrations of levetiracetam after administration orally as a solution and as a tablet. The possibility that saliva concentrations of the drug are altered by contamination in the buccal cavity was also examined. METHODS: 4 healthy male subjects received a single 750 mg oral dose of levetiracetam as a 10% solution and 4 subjects received three 250 mg tablets (750 mg). Levetiracetam concentrations in plasma and saliva were monitored for 24 hours post dose. RESULTS: In subjects receiving the levetiracetam solution, maximum saliva concentrations were observed at the first collection point (15 min) after administration and these were 19-74 times higher than corresponding plasma levels. The mean saliva/plasma ratio rapidly decreased thereafter, becoming stable after 4 hours. In subjects receiving tablets, levetiracetam concentration profiles for saliva paralleled the plasma concentration profiles with a fairly constant saliva/plasma concentration ratio throughout the 24-hour sampling period. A significant linear correlation between levetiracetam saliva and plasma concentrations was demonstrated (Pearson r = 0.88; p < 0.001 for tablet (n = 35) and r = 0.87; p < 0.001 for solution at times > or = 4 hours post-dose (n = 20)). The saliva to plasma concentration ratio was 1.11 (95% confidence interval: 0.99 - 1.22) following tablet intake, and 1.55 (95% CI: 1.34 1.77) following oral solution (> or = 4 hours post dose). CONCLUSIONS: Using saliva to monitor therapeutic exposure to levetiracetam is feasible beginning 15 minutes after tablet intake but beginning 4 hours after intake of an oral solution.     

Isosorbide dinitrate plasma concentrations and bioavailability in human subjects after administration of standard oral and sublingual formulations

The bioavailability of isosorbide dinitrate from formulations containing 5, 10, and 20 mg in tablets and 10 mg in solution for oral use and 5 mg in tablets for sublingual use, has been compared. When adjusted for dose, the peak mean plasma drug concentrations after oral administration were similar (e.g., 9.2 ng/mL after a 10-mg tablet) and about one-half that obtained after sublingual administration. Drug concentrations declined monoexponentially with mean half-lives ranging from 25-36 min. The relative bioavailability of isosorbide dinitrate from the oral formulations was not significantly different (p greater than 0.05) over the dose range studied, whereas the relative bioavailability after sublingual administration was about twice as great (p less than 0.01) as that after oral administration. The plasma drug concentration-time profile after administering the 5-mg sublingual tablet was similar to that obtained after administering orally a solution containing 10 mg, indicating that the latter should be as clinically effective as the former.     

Review of zolmitriptan and its clinical applications in migraine

Preclinical studies have shown that zolmitriptan is a selective serotonin 5-HT_1B/1D receptor agonist (triptan). Randomised, placebo-controlled, double-blind trials in patients with migraine have shown that zolmitriptan has good efficacy measured using 2 h response and pain-free rates. Migraine-associated symptoms, including nausea, photophobia and phonophobia, are also improved with zolmitriptan. Oral zolmitriptan (2.5 and 5 mg) has an onset of action within 45 min and efficacy is sustained in most patients who respond at 2 h. The orally-disintegrating zolmitriptan tablet has the advantage that it may be taken immediately, without the need for additional fluids, any time a migraine headache occurs. Patients may benefit in terms of improved efficacy from the convenience of the disintegrating tablet, since there is evidence that taking triptan therapy as early as possible in an attack is advantageous. For similar reasons, as well as improved efficacy, a nasal spray formulation is in development. Zolmitriptan is effective in the treatment of migraine associated with menses and migraine with aura. There is no tachyphylaxis following repeated doses for multiple attacks of migraine over a prolonged period of time. Compared to placebo, the incidence of persistent migraine headache is reduced by zolmitriptan and recurrent migraine headache occurs less frequently. Zolmitriptan has also shown efficacy in the treatment of persistent and/or recurrent migraine headache. Comparative clinical studies have shown overall that zolmitriptan has similar or superior efficacy to sumatriptan in the treatment of migraine. Specifically, zolmitriptan 2.5 mg was significantly more effective than sumatriptan 25 or 50 mg according to a number of end points, including headache response at 2 h. Oral zolmitriptan is also effective in the acute treatment of cluster headache. Zolmitriptan is generally well tolerated, with most adverse events being mild-to-moderate, transient and resolving without intervention or the need for treatment withdrawal. The consistent efficacy in treating all types of migraine and the choice of available formulations make zolmitriptan acceptable to patients and a suitable first-line therapy for the treatment of migraine.     

Relative bioavailability of ofloxacin tablets in comparison to oral solution

Single oral doses of solution and tablet preparations of 300 mg ofloxacin were given to 13 healthy male volunteers in an open, randomized crossover study. Concentrations of the unchanged drug were monitored at various times in serum and urine, over 28 hours and 48 hours, respectively. Each dose was followed by a 1-week washout period. Drug concentrations were measured both by a specific high pressure liquid chromatography (HPLC) method and a microbiological assay. A linear distribution independent regression analysis for method comparisons was calculated and good agreement between the two methods was found. Medians of maximum serum concentrations (Cmax) of ofloxacin after oral solution and tablet form were 5.0 mg/l and 3.5 mg/l, respectively. The times to maximal serum concentration (tmax) were 0.5 hr and 1.0 hr, respectively. The lower Cmax and later tmax after the tablet form were both statistically (p less than 0.05) different when compared to the corresponding values after the oral solution. However, the areas under the serum concentration-time curves (AUC0-28), as also the urinary recoveries did not differ significantly, showing that only the speed of absorption, but not the bioavailability of the tablet is changed in comparison to the oral solution form. Long-lasting, clinically relevant urine concentrations of ofloxacin were observed after both forms until the last collecting fraction (36 to 48 hours after medication). General tolerability was good; no side-effects were reported.