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PubMed2000

Selegiline for Alzheimer's disease.

BACKGROUND: Alzheimer's disease is the most common cause of dementia in older people accounting for some 60% of cases with late-onset cognitive deterioration. It is now thought that several neurotransmitter dysfunctions are involved from an early stage in the pathogenesis of Alzheimer's disease-associated cognitive decline. The efficacy of selegiline for symptoms of Alzheimer's disease remains controversial and is reflected by its low rate of prescription and the lack of approval by several regulatory authorities in Europe and elsewhere. Reasons for this uncertainty involve the modest overall effects observed in some trials, the lack of benefit observed in several trials, the use of cross-over designs which harbour methodological problems in a disease like dementia and the difficulty in interpreting results from trials when a variety of measurement scales are used to assess outcomes. OBJECTIVES: The objective of this review is to assess whether or not selegiline improves the well-being of patients with Alzheimer's disease. SEARCH STRATEGY: The Cochrane Dementia and Cognitive Impairment Group Register of Clinical Trials, was searched using the terms 'selegiline', 'l-deprenyl', "eldepryl" and "monamine oxidase inhibitor-B". MEDLINE, PsycLIT and EMBASE electronic databases were searched with the above terms in addition to using the group strategy (see group details) to limit the searches to randomised controlled trials. SELECTION CRITERIA: All unconfounded, double-blind, randomised controlled trials in which treatment with selegiline was administered for more than a day and compared to placebo in patients with dementia. DATA COLLECTION AND ANALYSIS: Data were extracted independently by the reviewers (JSB & LF), pooled where appropriate and possible, and the weighted or standardised mean differences (95%CI) estimated. Where possible, intention-to-treat data were used but usually the meta analyses were restricted to completers' data (data on people who completed the study). MAIN RESULTS: There are 15 included trials. All trials examined the cognitive effects of selegiline, and in addition, 12 trials examined the behavioural and mood effects. The results of 8 trials suggested some beneficial effect of selegiline in the treatment of cognitive deficits and in 3 trials in the treatment of behaviour and mood. The meta-analysis revealed benefits on memory function as evidenced by improvement in the memory tests from several cognitive tests. Pooling the data for all cognitive tests suggested significant benefits in those subjects treated with selegiline as compared to controls. There were benefits in mood and behaviour as demonstrated by measurements on the Brief Psychiatric Rating Scale and the Dementia Mood Assessment Scale. The global rating scales showed no effect of selegiline. Unfortunately, the evidence using standardised global cognitive scales was extremely limited, for both the MMSE and ADAS-cog. A variety of adverse effects were recorded, but very few patients left a trial as a direct result of the intervention. REVIEWER'S CONCLUSIONS: Although the evidence for a beneficial effect of selegiline on patients with Alzheimer's disease is promising there is not yet enough evidence to recommend its use routinely in practice. The individual patient data review will yield further evidence on the effects of selegiline compared to control as would additional studies evaluating the use of selegiline for the endpoints of standardised cognitive scales, clinician impression of global change, dependency and caregiver quality of life.

Alzheimer Disease↗

PubMedDate not supplied

In vitro formation of selegiline-N-oxide as a metabolite of selegiline in human, hamster, mouse, rat, guinea-pig, rabbit and dog.

It is well established in the litrature, that selegiline is metabolised to its N-dealkylated metabolites, N-desmethylselegiline, methamphetamine and amphetamine. However, most studies on selegiline metabolism did not characterize the species differences in the formation of the metabolites. Therefore, in this study, we investigated the in vitro metabolism of selegiline in liver microsomes of different species. In addition, to the previously well-characterized metabolites, selegiline-N-oxide (selegiline-NO) was found to be formed as a metabolite of selegiline in rat liver microsomal preparation. The results of experiments with liver microsomes from other species indicated species differences in the rate and extent of formation of selegiline-NO. The dog and hamster liver microsomal preparations were the most active in terms of selegiline-NO production, whereas little selegiline was metabolized to its N-oxide in human liver microsomes. When selegiline-NO was incubated with rat liver microsomes, no metabolism occurred. When a short incubation time was applied in selegiline expriments no increase in the amount of selegiline-NO was detected. Accordingly, it was clear that selegiline was not metabolized to the N-dealkylated or N,N-bis-dealkylated compounds via selegiline-NO. Studies with different isoenzyme inhibitors indicated that the formation of selegiline-NO might be catalyzed at least partly by cytochrome P450 (CYP) 2D6 and CYP3A4. With the exception of hamster microsomes in the microsomal preparations in vitro, the formation of the R,S-stereoisomer of selegiline-NO was preferred.

Animals↗

PubMed1992

Toxicological detection of selegiline and its metabolites in urine using fluorescence polarization immunoassay (FPIA) and gas chromatography-mass spectrometry (GC-MS) and differentiation by enantioselective GC-MS of the intake of selegiline from abuse of methamphetamine or amphetamine.

Selegiline (R(-)-N-methyl-N-(1-phenyl-2-propyl)-2-propinylamine), a selective MAO-B inhibitor used as an antiparkinsonian, is excreted in urine as N-desmethyl selegiline (norselegiline), R(-)-methamphetamine (R(-)-MA), R(-)-amphetamine (R(-)-AM) and their conjugated p-hydroxy derivatives. We found that the fluorescence polarization immunoassays (FPIA) TDx amphetamine/methamphetamine II (AM/MA II) and TDx amphetamine class (AM class) lead to positive results for up to 2 days after a single oral dose of 10 mg selegiline (detection limit: 0.1 mg/l, each). Every urine specimen from long term selegiline patients (10 mg/day) showed positive TDx results during the selegiline regimen. Positive TDx results were confirmed using gas chromatography-mass spectrometry (GC-MS). Selegiline metabolites, particularly MA, could be detected in urine for up to 7 days after intake of a single oral dose of 10 mg selegiline (detection limit: 0.01 mg/l for MA and AM). Norselegiline, the only specific selegiline metabolite, was only detectable for about 12 h. Moreover, norselegiline was not detected in all urine samples from long term selegiline patients (10 mg/day). Since differentiation of selegiline intake from MA/AM abuse by detecting norselegiline was not possible in most cases, an enantioselective GC-MS procedure was developed. It allowed differentiation of the enantiomers of the selegiline metabolites and thereby separation of selegiline intake (only R(-)-enantiomers) from methamphetamine and/or amphetamine abuse (racemates or S(+)-enantiomers). After derivatization with S(-)-N-trifluoroacetyl-prolyl chloride (TPC), the two enantiomers of MA and AM were each separated as diastereomers employing the routinely used achiral GC capillary.(ABSTRACT TRUNCATED AT 250 WORDS)

Amphetamine↗

PubMed1999

Stereoselective analyses of selegiline metabolites: possible urinary markers for selegiline therapy.

The stereoselective analysis of selegiline metabolites in human urine and plasma by gas chromatography using the chiral column with the non-chiral reagent was investigated for the differentiation of selegiline therapy from the methamphetamine (MA) abuse. This method gave clear separations of MA and amphetamine (AM) isomers without any artifactual optical-opposite peaks due to the reagent. After the administration of selegiline tablets, desmethylselegiline (DMS), MA and AM were observed as (-)-isomers in the urine and plasma. Within the first 48 h after dosing, approximately 40% of selegiline administered was excreted in urine as these three metabolites. The parent drug, selegiline, was not detected in any urine or plasma samples. On the other hand, MA and AM were observed only as (+)-isomers in the urine of MA abusers. For the distinction of selegiline users from street MA abusers in urinalysis, (-)-DMS, a specific metabolite of selegiline, was not a suitable marker. (-)-DMS rapidly disappeared from urine and was excreted only 1% of the given dose. By the moment analysis with the trapezoidal integration, the mean residence times of (-)-DMS in plasma and urine were 2.7 and 3.8 h, respectively, which were 5-20 times shorter than those of (-)-MA or (-)-AM. The values of AM/MA in the urine increased from 0.24 to 0.67 (r = 0.857) along with time after the selegiline administration. This ratio was not a sufficient marker to differentiate selegiline users from MA abusers, although the values of AM/MA in 74% of MA abusers were less than 0.24. The present GC technique improved the chiral analyses of MA and AM. This chiral analysis is the most useful technique to avoid the misinterpretation in the discrimination between clinical selegiline therapy and illicit MA use.

Adult↗

PubMed1990

Effect of selegiline and desmethyl-selegiline on cortical electric activity in rats.

The pharmaco-EEG changes caused by the monoamine oxidase (MAO) B inhibitor selegiline were compared with the frequency band alterations aroused by its desmethyl metabolite after oral administration in rats. After single administration (5 mg/kg) the EEG changes caused by selegiline or desmethyl-selegiline differed significantly. Distinct decreases in delta and clear increases in theta EEG frequency bands were obvious after administration of selegiline. The single oral dose of desmethyl-selegiline (5 mg/kg) caused only trendly the same EEG changes observed after giving the mother compound. Following repeated administration on four consecutive days no significant differences in the frequency band changes could be seen after selegiline or desmethyl-selegiline. Based on present results it is likely that the mode of action of desmethyl-selegiline appears to be similar or identical with the mode of action of the parent compound, selegiline.

Amphetamines↗

PubMed2000

Different neurorescue profiles of selegiline and p-fluoro-selegiline in gerbils.

The neuroprotective/neuronal rescue effects of selegiline are not exactly understood, and show great variability in clinical trials. In this study, the dose-dependence of neuronal rescue potency of selegiline and its analogue para-fluoro-selegiline (PFS) was investigated in gerbils. The compounds were tested in a transient global cerebral ischemia model. Selegiline expressed a bell-shaped, dose-response curve with high intrinsic activity (with greatest effect at 0.001 mg/kg), as opposed to PFS which shows a saturation profile. These findings indicate possible therapeutic differences between PFS and selegiline in the treatment of neurodegenerative disorders. Inhibition of progression of the disease (neuroprotective effect) and improvements of symptoms (MAO-B inhibition) may occur at the same dose level using PFS, while these doses are separated in case of selegiline.

Animals↗

PubMed1993

Symptomatic effect of selegiline in de novo Parkinsonian patients. The French Selegiline Multicenter Trial.

The French Selegiline Multicenter Trial was carried out in 1990 to investigate whether the disability of de novo patients with parkinsonism could be improved during the first 3 months by monotherapy with selegiline (10 mg/day). A double-blind, randomized, placebo-controlled clinical trial was conducted over 3 months with 93 patients from 13 centers. Symptomatology was assessed on various disease rating scales, including Hoehn and Yahr, Hamilton Depression Rating Scale, Unified Parkinson's Disease rating scale, and Schwab and England scores, as well as self-assessment. Biological and clinical parameters were measured for tolerability, and efficacy was investigated with special reference to the point at which therapy with L-dopa had to be started. Selegiline was significantly superior to placebo on the various motor rating scores, and depressive scores were significantly improved at the end of 3 months. Adverse effects were rare and minor. Therefore, selegiline could be the therapy of choice for the treatment of de novo parkinsonian patients.

Activities of Daily Living↗

PubMed1997

Pharmacokinetics and bioequivalence of the main metabolites of selegiline: desmethylselegiline, methamphetamine and amphetamine after oral administration of selegiline.

A bioavailability study of 2 different selegiline preparations were conducted in 20 healthy volunteers to test the bioequivalence. Almost no bioavailability study of selegiline has been published. As plasma levels of selegiline are very low and the elimination half-life is very short being about 9 minutes, therefore, a very sensitive and selective method for determining the 3 main metabolites desmethylselegiline (DMS), methamphetamine (MA) and amphetamine (A) was developed. After application of a single oral dose of 5 mg selegiline the Cmax values of DMS reached 5-6 ng/ml, of MA 6-7 ng/ml and of A about 2 ng/ml. The AUC infinity values were with DMS about 11 ng/ml x h +/- 4.5, with MA about 130 g/ml x h +/- 50 and with A about 50 ng/ml x h +/- 15. The 90% confidence interval was with logarithmic transformed AUC infinity values 92-107% with DMS, 89-107% with MA, and 84-104% with A. The logarithmic transformed Cmax values showed a 90% confidence interval of 92-127% with DMS, 91-101% with MA, and 90-103% with A. All relevant pharmacokinetic parameters showed bioequivalence with all 3 metabolites (DMS, MA, and A).

Administration, Oral↗

PubMed1990

Kinetic evaluation of MAO-B-activity following oral administration of selegiline and desmethyl-selegiline in the rat.

The monoamine oxidase (MAO) B activity of rat brain was inhibited by selegiline and its desmethyl-metabolite in vitro with IC50-values of 11.25 nmol/l and 625.00 nmol/l, respectively. When measured in an ex vivo experiment following oral treatment of rats, the large difference in potency was distinctly reduced, from factor 60 in vitro to factor 3 ex vivo. Restoration experiments of MAO-B-activity after cessation of treatment revealed a nearly identical time course for both compounds. It is concluded that desmethyl-selegiline is an irreversible blocker of MAO-B, nearly equipotent to selegiline after multiple oral administration. No pharmacologically relevant inhibition of MAO-A was found with both compounds.

Administration, Oral↗

PubMed2001

Incorporation of selegiline metabolites into hair after oral selegiline intake.

We have previously shown that melanin in human hair has a great impact on the incorporation of codeine into hair. The present study on 10 subjects was performed to investigate whether or not these findings could also be extrapolated to other therapeutic drugs. We chose selegiline because it metabolizes to two commonly abused central stimulants, methamphetamine and amphetamine. The results would therefore also be of interest when studying the intake of such drugs and their incorporation into human hair. Selegiline and metabolites were determined by gas chromatography-mass spectrometry, total melanin by spectrophotometry, and pyrrole-tricarboxylic acid by high-performance liquid chromatography with ultraviolet detection. Our results show strong positive exponential relationships (y = e(x)) between melanin and the metabolites, which for methamphetamine improved by normalizing for plasma area under the curve. We conclude that the major metabolites of selegiline can be detected in hair up to four weeks after a single oral dose and that the incorporation closely relates to the melanin contents.

Administration, Oral↗

PubMed2001

Simultaneous determination of selegiline-N-oxide, a new indicator for selegiline administration, and other metabolites in urine by high-performance liquid chromatography-electrospray ionization mass spectrometry.

In order to discriminate selegiline (SG) use from methamphetamine (MA) use, the urinary metabolites of SG users have been investigated using high-performance liquid chromatography (HPLC)-electrospray ionization mass spectrometry (HPLC-ESI-MS). Selegiline-N-oxide (SGO), a specific metabolite of SG, was for the first time detected in the urine, in addition to other metabolites MA, amphetamine (AP) and desmethylselegiline (DM-SG). A combination of a Sep-pak C18 cartridge for the solid-phase extraction, a semi-micro SCX column (1.5 mm I.D.x 150 mm) for HPLC separation and ESI-MS for detection provided a simple and sensitive procedure for the simultaneous determination of these analytes. Acetonitrile-10 mM ammonium formate buffer adjusted to pH 3.0 (70:30, v/v) at a flow-rate of 0.1 ml/min was found to be the most effective mobile phase. Linear calibration curves were obtained over the concentration range from 0.5 to 100 ng/ml for all the analytes by monitoring each protonated molecular ion in the selected ion monitoring (SIM) mode. The detection limits ranged from 0.1 to 0.5 ng/ml. Upon applying the scan mode, 10-20 ng/ml were the detection limits. Quantitative investigation utilizing this revealed that SGO was about three times more abundant (47 ng/ml, 79 ng/ml) than DM-SG in two SG users' urine samples tested here. This newly-detected, specific metabolite SGO was found to be an effective indicator for SG administration.

Chromatography, High Pressure Liquid↗

PubMed2002

Urinary excretion of selegiline N-oxide, a new indicator for selegiline administration in man.

1. The metabolism of selegiline (SG) has been studied by investigating the time-course of urinary excretion of SG and its metabolites using high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI MS) in combination with solid-phase extraction. 2. The excretion profiles of SG and its four major metabolites, selegiline-N-oxide (SGO), N-desmethylselegiline (DM-SG), methamphetamine (MA) and amphetamine (AP), were investigated in six healthy volunteers after oral administrations of SG hydrochloride in a single dose of 2.5 or 7.5mg, and a repeat twice-daily dose of 5.0 mg day(-1) (for 3 days). 3. The cumulative amount of SGO excreted within approximately the first 8-12h was comparable with MA, and the amount in the first 72 h was 2.0-7.8 times larger (2.8-13.2% of the dose) than that of DM-SG. 4. These results demonstrate that SGO can be used in place of DM-SG, which is known to be a main specific metabolite of SG, as a new indicator for the discrimination of SG use compared with MA abuse.

Adrenergic Uptake Inhibitors↗

PubMed1991

Selegiline in de novo parkinsonian patients: the French selegiline multicenter trial (FSMT).

The French selegiline multicenter trial was conducted in 1990 to test the possibility to improve disability of de novo parkinsonian patients (P.P.) during the first three months of treatment with selegiline (S) (10 mg/day) monotherapy. 93 P.P. were included in this double-blind, randomized, placebo controlled, clinical trial, in which 13 centers participated. Both parallel groups were followed up from inclusion (D0) to D30, D60 and D90. Drug efficacy was judged with Hoehn and Yahr (HY), Hamilton Depression Rating Scale (HDRS), Unified Parkinson's Disease Rating Scale (UPDRS), Schwab and England scores, decision to introduce levodopa and selfassessment. Biological and clinical parameters (cardio- vascular, weight, side-effects reports) were assessed for tolerability. 84 P.P. (38 P, 46 S) were evaluable for efficacy at D90. When considering the main parameters, S appears superior to placebo: HY scores (p less than 0.001), global UPDRS scores (p less than 0.001) and UPDRS subscores: mental (p less than 0.001), daily living activities (p less than 0.01), motor activities (p less than 0.01). Depressive scores (HDRS) are significantly improved only at D90 (p = 0.005). Levodopa therapy was introduced in 45% of the cases in S groups versus 18.4% in P group. Global impression of efficacy was largely in favor of S; failure was noted in half of the cases in P group and only in 1/5th of the cases in S group. Side-effects were rare and minor. S 10 mg/day monotherapy is statistically superior to placebo in improving de novo P.P. during the first three months treatment. Motor symptoms rapidly improve; mood is only modified after 3 months. S appears to be well tolerated. S may be considered as a good candidate for the initial treatment of P.P.

Aged↗

PubMed2006

High-performance liquid chromatographic-mass spectrometric determination of methamphetamine and amphetamine enantiomers, desmethylselegiline and selegiline, in hair samples of long-term methamphetamine abusers or selegiline users.

We devised a highly sensitive method for simultaneously determining methamphetamine (MA) and amphetamine (AP) enantiomers, desmethylselegiline (DMSG) and selegiline (SG), in human hair using a derivatization technique and high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS). MA and AP enantiomers and DMSG were effectively converted to trifluoroacetic acid (TFA) derivatives, and the sensitivity of MA and DMSG increased five times over compared with that of free bases. The TFA derivatives of each compound were stable within one week in a stock solution of methanol or for 24 h in the HPLC mobile phase (mixture of methanol and ammonium formate buffer). Each compound was well separated, and calibration curves were linear in the concentration range 0.04-40 ng/mg for MA enantiomers, SG and DMSG, and 0.2-40 ng/mg for AP enantiomers. The accuracy and precision of the method were evaluated, and relative standard deviations were within 7%. Our method was successfully applied to hair samples obtained from long-term MA abusers and SG users. (+)-MA and (+)-AP were detected from three MA abusers at concentrations of 0.79-20.85 and 0.04-3.30 ng/mg, respectively. On the other hand, (-)-MA, (-)-AP, DMSG, and SG were detected in three SG users at concentrations of 2.48-9.05, 0.72-3.10, 0.12-0.59, and 0-0.04 ng/mg, respectively. Based on our obtained data, discrimination of MA abusers from SG users was considered to be possible by comparing optical isomers of MA and AP, the existence of DMSG and/or SG, and the concentration ratio of AP to MA in hair samples.

Amphetamine↗

PubMedDate not supplied

[Monotherapy trial with selegiline in de novo parkinsonian patients] Members of the French research group for testing selegiline in early Parkinson disease].

The French selegiline (S) multicenter trial was conducted in 1990 to test the possibility to improve symptomatology of de novo parkinsonian patients (PP) during the first three months of treatment by monotherapy S 10 mg/day. A randomized double blind placebo, parallel controlled trial was carried out on 93 patients in 13 neurologic centers. S appears superior to placebo. Global scores and motor subscores of UPDRS are improved (p < 0.001, p < 0.01) from the first to the third month. Side effects are minor (nausea, dysgueusia, vertigo, lipothymia) and hardly different in both groups. S thus appears as inducing a rapid and moderate symptomatic effect in de novo PP, during a 3 months long period of treatment.

Aged↗

PubMed2003

A new low-dose formulation of selegiline: clinical efficacy, patient preference and selectivity for MAO-B inhibition.

Three studies were performed using a fast dissolving formulation of selegiline hydrochloride designed for buccal absorption "Zydis Selegiline". The aim of the first study was to compare the therapeutic efficacy of Zydis Selegiline (1.25 mg or 10 mg) with conventional selegiline hydrochloride tablets "conventional selegiline tablets" (10 mg) in patients with Parkinson's disease (PD) who were previously treated with conventional selegiline tablets as an adjunct to levodopa/dopamine agonist therapy. Patients were observed for 4 weeks to ensure that they were stable. Stable patients (n=197) were then randomised to continue with conventional selegiline tablets 10 mg (n=68), or to treatment with Zydis Selegiline 1.25 mg (n=64) or Zydis Selegiline 10 mg (n=62) for 12 weeks in this randomised, parallel group study. A further aim was to establish the acceptability of Zydis Selegiline compared with conventional selegiline tablets. Patient preference for Zydis Selegiline was also evaluated in a second study, a single-dose, randomised, two-way crossover study conducted in patients with PD (n=148). Patients were stratified by the presence or absence of swallowing and salivation problems and were randomised to either Zydis Selegiline 5 mg or a placebo fast-dissolving formulation. In a third study, the degree of potentiation of the tyramine pressor effect following Zydis Selegiline was compared with that following conventional selegiline tablets in healthy volunteers. A total of 24 healthy volunteers were randomised to receive Zydis Selegiline 1.25 mg or conventional selegiline tablets 10 mg for 14-16 days in an open-label, randomised parallel group study. Both Zydis Selegiline (1.25 mg and 10 mg) treatments were shown to be therapeutically equivalent to conventional selegiline tablets 10 mg based on comparison of mean total Unified Parkinson's Disease Rating Scale (UPDRS) scores. Therapeutic equivalence was defined a priori as the 90% confidence interval (CI) for the difference in total UPDRS scores between groups to lie entirely within the range +/-5. The difference (90% CI) in mean adjusted total UPDRS between Zydis Selegiline 1.25 mg and conventional selegiline tablets 10 mg was -2.50 (-4.84, -0.17), and for Zydis Selegiline 10 mg and conventional selegiline tablets 10 mg, 0.04 (-2.30, 2.38). For the motor subscores of the UPDRS, differences between adjusted means (90% CI) compared with the conventional selegiline tablets group were: Zydis Selegiline 1.25 mg, -2.14 (-3.94, -0.33) and Zydis Selegiline 10 mg, -0.90 (-2.70, +0.91). Patients who switched from conventional selegiline tablets to Zydis Selegiline 1.25 mg showed a slight improvement in UPDRS scores following 12 weeks of treatment (standard error of difference 1.039; p=0.01). In the single-dose crossover study, most (61%) patients liked Zydis Selegiline 5 mg; a significantly greater proportion than the null hypothesis of 50% (p<0.002). However, only 62 patients (46%) indicated that they liked the taste of Zydis Selegiline. Nevertheless, the proportion of patients who preferred Zydis Selegiline (65%) to their usual medication was significantly greater than the null hypothesis of 50% (p<0.001). Similar findings were demonstrated in the 12-week study where a higher proportion of patients who received up to 3 months of treatment indicated a preference for either Zydis Selegiline 1.25 mg (90%) or Zydis Selegiline 10 mg (86%) over conventional selegiline tablets 10 mg. More than 90% of patients found Zydis Selegiline easy to take, with 61% rating it as extremely easy. Most (81%) patients taking Zydis Selegiline 1.25 mg liked the taste compared with 45% taking Zydis Selegiline 5 mg (in the previous study). Zydis Selegiline did not potentiate the tyramine effect: a pressor effect was elicited after 400 mg tyramine both before and after 14 days of treatment with Zydis Selegiline 1.25 mg. In contrast, after 14 days treatment with conventional selegiline tablets 10 mg, the threshold dose required to elicit the tyramine pressor response was significantly (p<0.0001) reduced from 400 mg to 200 mg. In summary, Zydis Selegiline at doses of 1.25 mg and 10 mg was therapeutically equivalent to conventional selegiline tablets 10 mg. The Zydis Selegiline formulation was well-liked by all patients, with most preferring Zydis Selegiline 1.25 mg to their usual selegiline tablet. Furthermore, Zydis Selegiline was well tolerated and, unlike conventional selegiline tablets, appeared to retain specificity for inhibition of monoamine oxidase type B (MAO-B), since it did not potentiate the pressor response to tyramine.

Administration, Oral↗

PubMed2003

A new formulation of selegiline: improved bioavailability and selectivity for MAO-B inhibition.

Seven randomised comparative studies were conducted in healthy volunteers to compare the pharmacokinetic and pharmacodynamic profiles of selegiline hydrochloride in a new formulation designed for buccal absorption "Zydis Selegiline" (1.25-10 mg) with conventional selegiline hydrochloride tablets "conventional selegiline tablets" (10 mg). A total of 156 healthy volunteers participated in these studies. Plasma concentrations of selegiline and its primary metabolites, N-desmethylselegiline (DMS), l-amphetamine (AMT), and l-methamphetamine (MET) were measured using Gas Chromatography Mass Spectrometry (GCMS) and gas liquid chromatography (GLC) assays. Inhibition of monoamine-oxidase type B (MAO-B) and monoamine oxidase type A (MAO-A) activity was determined by measurement of as beta-phenylethylamine (PEA) by GCMS and 5-hydroxyindoleacetic acid (5-HIAA) by High Performance Liquid Chromatography (HPLC) assays. Almost a third (2.96 mg) of a 10 mg selegiline dose in Zydis Selegiline was absorbed pre-gastrically (predominantly buccally) within 1 minute. Mean [SD] area-under-the curve (AUC(0- infinity)) values following Zydis Selegiline 10 mg (5.85 [7.31] ng.h/mL) were approximately five times higher than those following conventional selegiline tablets 10 mg (1.16 [1.05] ng.h/mL). In contrast, plasma concentrations of metabolites were significantly ( p<0.001) lower following Zydis Selegiline 10 mg than following conventional selegiline tablets 10 mg. Plasma concentrations of selegiline and its metabolites increased in a dose-dependent manner over the dose-range Zydis Selegiline 1.25-5 mg. Bioavailability was determined using AUC and peak plasma concentrations (C(max)). The C(max) of selegiline was similar following administration of Zydis Selegiline 1.25 mg (1.52 ng/mL) or conventional selegiline tablets 10 mg (1.14 mg/mL). The range of values for AUC(0- infinity) and C(max) following Zydis Selegiline 1.25 mg were entirely contained within the range following conventional selegiline tablets 10 mg, with a much higher variability of plasma selegiline concentrations occurring after conventional selegiline tablets than after Zydis Selegiline. As expected, peak plasma concentrations for DMS, AMT and MET were consistently lower after Zydis Selegiline 1.25 mg (1.19, 0.34, 0.93 ng/ml, respectively) than after conventional selegiline tablets 10 mg (18.37, 3.60, 12.92 ng/ml, respectively). A significant (r=0.0001) correlation between daily PEA excretion (a measure of brain MAO-B inhibition) and the log-transformed AUC((0-t)) for selegiline was demonstrated. Mean daily PEA excretion was similar following Zydis Selegiline 1.25 mg and conventional selegiline tablets 10 mg (13.0 microg versus 17.6 microg). In contrast, there was no correlation between PEA excretion and selegiline metabolites, indicating that selegiline metabolites do not significantly inhibit MAO-B. Urinary excretion of 5-HIAA (used as a marker for MAO-A inhibition) was unrelated to plasma concentrations of selegiline or DMS following single or repeat dosing of Zydis Selegiline 1.25 mg or conventional selegiline tablets 10 mg. However, comparison of treatment groups revealed a significantly lower excretion of 5-HIAA in the conventional selegiline tablets 10 mg group than in the Zydis Selegiline 1.25 mg group after repeated administration over 13 days. In summary, by reducing the opportunity for first-pass metabolism, the absorption of selegiline from Zydis Selegiline was more efficient and less variable than from conventional selegiline tablets. Compared with conventional selegiline tablets 10 mg, Zydis Selegiline 1.25 mg yielded similar plasma concentrations of selegiline and degree of MAO-B inhibition, but markedly reduced concentrations of the principal metabolites. Thus, the lower but equally MAO-B inhibitory dose of selegiline in Zydis Selegiline 1.25 mg, which is associated with lower concentrations of potentially harmful metabolites, could offer a safer and more predictable treatment in the management of patients with Parkinson's disease.

Administration, Oral↗

PubMed1997

Clinical pharmacokinetics and pharmacodynamics of selegiline. An update.

Selegiline is a selective inhibitor of monoamine oxidase-B (MAO-B) at a dose of 10 mg/day and is given to patients with Parkinson's disease as an adjunct to levodopa therapy. By inhibiting MAO-B, selegiline increases the dopamine levels in the substantia nigra. Selegiline also blocks dopamine re-uptake from the synaptic cleft, thus increasing the dopamine concentrations in the brain. At a dose of 10 mg/day, selegiline is devoid of 'cheese effect'. The pharmacokinetics of selegiline are highly variable. Following an oral dose of selegiline 10 mg, it is rapidly absorbed and metabolised to desmethylselegiline, levoamphetamine and levomethamphetamine. The mean peak plasma concentration (Cmax) is approximately 2 micrograms/L and the time to reach the peak is under an hour. The absolute bioavailability of selegiline is approximately 10%. It has an apparent volume of distribution of 1854 L. The oral clearance of selegiline (59 L/min) is many fold higher than the liver blood flow (1.5 L/min), indicating that extrahepatic processes are involved in the elimination of selegiline. The elimination half-life of selegiline is about 1.5 hours. Following multiple administration of selegiline 10 mg/day, the accumulation of both the parent compound and its metabolites have been reported. At least a 4-fold increase in the half-lives of selegiline and desmethylselegiline has been reported. There is at least a 3-fold increase in the Cmax and area under the concentration-time curve of selegiline with food. One of the metabolites of selegiline, desmethylselegiline, is believed to posses some MAO-B inhibitory property, though to a lesser extent than that of selegiline. Within 2 to 4 hours of an oral dose of selegiline 10 mg, 86% of the platelet MAO-B activity was inhibited and it took almost 2 weeks for platelet MAO-B activity to return to the baseline values. Transdermal administration of selegiline resulted in an increase in the plasma concentrations of selegiline and a decrease in the formation of its metabolites, indicating that the extensive first-pass effect is avoided when selegiline is given transdermally.

Administration, Cutaneous↗