Selegiline Research Articles

Preliminary study on cytotoxicity of selegiline on different cancer cell lines: exploration of the induction of ROS-independent apoptosis in breast cancer cells.

The concept of drug repurposing is now widely utilized by biomedical scientists for drug discovery. An example of this is the use of selegiline (SEL), a monoamine oxidase inhibitor that was initially used for the management of depression but is now being considered for another purpose. This study compares the cytotoxic effects of SEL on different cancer cells. Further, the study explores the molecular mechanism of cell death, validating the possibility of its repurposing for cancer. Preliminary analysis of network pharmacological data was conducted in silico, followed by in vitro cytotoxicity tests on PC12, G361, MDA-MB231, MCF7, THP-1, and Hela cells under normoxic and hypoxic conditions, using the MTT assay. The mechanism of cell death was then confirmed by performing DAPI and FITC-conjugated Annexin V and Propidium Iodide (PI) staining assays. Additionally, ROS levels and PKC phosphorylation were also evaluated. In silico analysis has revealed that SEL is associated with ten genes linked to different cancer types. Specifically, SEL was most cytotoxic to neuronal pheochromocytoma, triple-negative human epithelial breast cancer cells, and ER+ and PR+ breast cancer cells. Furthermore, it was observed that this cell death occurred through ROS-independent apoptosis pathways. In addition, SEL was found to inhibit the phosphorylation of PKC, which may contribute to cell death. SEL induces apoptosis in breast cancer cells independently of reactive oxygen species and inhibits the phosphorylation of protein kinase C, which merits further exploration.

Protective effects of selegiline against amyloid beta-induced anxiety-like behavior and memory impairment.

Alzheimer's disease (AD) is a complex and common neurodegenerative disorder. The present study aimed to investigate the potential effects of selegiline (SEL) on various aspects of memory performance, anxiety, and oxidative stress in an AD rat model induced by intracerebroventricular injection of amyloid beta1-42 (Aβ1-42). Oral administration of SEL at a dose of 0.5mg/kg/day was performed for 30 consecutive days. Following the 30 days, several tests, including the open-field, elevated plus-maze, novel object recognition, Morris water maze, and passive avoidance learning were conducted to assess locomotor activity, anxiety-like behavior, recognition memory, spatial memory, and passive avoidance memory, respectively. The results indicate that the induction of AD in rats led to recognition memory, spatial memory, and passive avoidance memory impairments, as well as increased anxiety. Additionally, the AD rats exhibited a decrease in total antioxidant capacity and an increase in total oxidant status levels, suggesting an imbalance in oxidative-antioxidant status. However, the administration of SEL improved memory performance, reduced anxiety, and modulated oxidative-antioxidant status in AD rats. These findings provide evidence that SEL may alleviate anxiety-like behavior and cognitive deficits induced by Aβ through modulation of oxidative-antioxidant status.

Enhancing selegiline hydrochloride efficacy: Box Behnken-optimized liposomal delivery via intranasal route for Parkinson’s disease intervention

The clinical use of selegiline hydrochloride in conventional dosage forms is to reduce the progression of Parkinson’s disease (PD). However, its limited access to the brain, short half-life, and first-pass metabolism minimize brain uptake. Nano-based liposomes offer promising tools for brain-targeted delivery of therapeutics, especially intranasally administered cationic liposomes that target the brain region via the olfactory route and reduce biodistribution. In the present work, cationic liposomes encapsulated with selegiline hydrochloride were fabricated for intranasal administration against PD. The liposomes were initially optimized by Box Behnken design, and the selected run was coated with stearylamine to provide a cationic charge to the liposomes. The final coated liposomes, SH-LP3, demonstrated a minimum size of 173 ± 2.13 nm, an ideal zeta potential of +16 ± 1.98, and achieved a maximum entrapment efficiency of 40.14 ± 1.83%. Morphology analysis showed the spherical shape of liposomes in the size range of 100–200 nm. The in vitro cytotoxicity assay in SHSY5Y cell lines showed a significant decrease in toxicity, almost ten times less, compared to pure selegiline hydrochloride. Animal studies on rotenone-lesioned C57BL6 mice model for PD were performed to investigate the effect of intranasally administered liposomes. The SH-LP3 formulation exhibited remarkable effectiveness in relieving symptoms of PD. This extensive analysis emphasizes the possibility of intranasally administered SH-LP3 liposomes as a feasible treatment option for PD. The formulation not only delivers continuous drug release but also displays better safety and efficacy, providing a platform for additional studies and growth in the domain of PD treatment.

Design Formulation and in vitro Evaluation of Gastroretentive Microspheres of Selegiline Hydrochloride for Parkinson’s Disease by Design Expert

Design Formulation and in vitro Evaluation of Gastroretentive Microspheres of Selegiline Hydrochloride for Parkinson’s Disease by Design Expert

Hepatoprotective Efficacy of Selegiline: Molecular Insight

Liver fibrosis is a form of wound healing that develops in response to persistent liver injury brought on by viruses, poisons, and medicines that are harmful to the liver. Inflammation is a hallmark of the condition, which is then followed by the formation of scar tissue via the deposition of extracellular matrix proteins. Hepatitis C virus (HCV) entrance has been linked to the host cofactor ephrin receptor A2 (EphA2). Selegiline hydrochloride is a levorotatory acetylenic derivative of phenethylamine. It is commonly referred to in the clinical and pharmacological literature as l-deprenyl. Selegiline (deprenyl) is a selective inhibitor of cerebral monoamine oxidase type B at the dosage (10 mg/day) used in patients with Parkinson's disease. Through this activity, the drug increases nigrostriatal dopamine levels, and may protect neurons against damage by free radicals and possibly exogenous neurotoxins.The exact mechanism of action for the hepatoprotective action of Selegiline was still not revealed. With intent to propose the most probable mechanism of action of Selegiline the docking based computational analysis has been performed against the hepatoprotective drug targets like PPARα enzyme.

Simultaneous determination of citalopram and selegiline using an efficient electrochemical sensor based on ZIF-8 decorated with RGO and g-C3N4 in real samples

A novel carbon paste electrode (CPE) modified with ZIF-8/g-C3N4/RGO nanocomposite is used as a high sensitive electrochemical sensor to simultaneously determine citalopram (CIT) and selegiline (SEL). Simultaneous determination of these drugs is important because of their effect on the level of neurotransmitter serotonin in the central nervous system (CNS) which can happen by overuse and concurrent consumption. Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) are used in order to investigate the electrochemical behavior of the electrode. Various techniques such as scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDX), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) are employed to affirm the structure of ZIF-8/g-C3N4/RGO nanocomposite. Excellent sensing performance of the suggested electrode is verified based on the low limit of detection of 0.008 μM and 0.014 μM which represent two linear ranges from 0.009 to 900 μM for CIT and 0.09–900 μM for SEL, respectively. The analytical performance of the proposed electrochemical sensor is investigated in real samples including human blood and urine with acceptable results.

Source identification of amphetamine-like stimulants in Spanish wastewater through enantiomeric profiling

Amphetamine (AMP), methamphetamine (MAMP) and 3,4-methylenedioxymethamphetamine (MDMA) occur in wastewater not only as a result of illicit consumption, but also, in some cases, from prescription drug use or by direct drug disposal into the sewage system. Enantiomeric profiling of these chiral drugs could give more insight into the origin of their occurrence. In this manuscript, a new analytical methodology for the enantiomeric analysis of amphetamine-like substances in wastewater has been developed. The method consists of a solid-phase extraction (SPE) followed by liquid chromatography-triple quadrupole-tandem mass spectrometry (LC-MS/MS), which showed low quantification limits in the 2.4–5.5 ng L−1 range. The LC-MS/MS method was first applied to characterize a total of 38 solid street drug samples anonymously provided by consumers. The results of these analysis showed that AMP and MDMA trafficked into Spain are synthesized as racemate, while MAMP is exclusively produced as the S(+)-enantiomer. Then, the analytical method was employed to analyse urban wastewater samples collected from the wastewater treatment plants (WWTPs) of five different cities in 2018 and 2019. Consumption estimated through normalized population loads in wastewater showed an increased pattern of AMP use in the Basque Country. Furthermore, the enantiomeric profiling of wastewater samples was contrasted to lisdexamfetamine (LIS) and selegiline (SEL) prescription figures, two pharmaceuticals which metabolize to S(+)-AMP, and to R(-)-AMP and R(-)-MAMP, respectively. From this analysis, and considering uncertainties derived from metabolism and adherence to treatment, it was concluded that LIS is a relevant source of AMP in those cases with low wastewater loads, i.e. up to a maximum of 60% of AMP detected in wastewater in some samples could originate from LIS prescription, while SEL does not represent a significant source of AMP nor MAMP. Finally, removal efficiencies could be evaluated for the WWTP (serving ca. 860,000 inhabitants) with higher AMP influent concentrations. The removal of AMP was satisfactory with rates higher than 99%, whereas MDMA showed an average removal of approximately 60%, accompanied by an enrichment of R(-)-MDMA.

Development and characterization of sublingual films for enhanced bioavailability of selegiline hydrochloride.

Low oral bioavailability of selegiline hydrochloride (SH) is primarily due to extensive first-pass metabolism and hence the need for an alternative pathway of administration. Herein, we report the development of sublingual SH films. The films were formulated with varying polymer composition (F1-F6) and evaluated for physicochemical characteristics, in vitro drug release and ex vivo permeation studies. The film F2 demonstrated satisfactory weight (10.60mg), folding endurance (>200), drug content (11.44mg/cm2), disintegration time (68s), mucoadhesive strength (47.7N/cm2), and controlled release for 30min. The permeation studies exhibited a higher ex vivo sublingual flux than that of the plain drug. This study concludes that the SH film can provide a potential opportunity for sublingual drug delivery.

Characterisation of Drug Delivery Efficacy Using Microstructure-Assisted Application of a Range of APIs.

Polymer-based solid microstructures (MSts) have the potential to significantly increase the quantity and range of drugs that can be administered across the skin. MSt arrays are used to demonstrate their capacity to bypass the skin barrier and enhance permeability by creating microchannels through the stratum corneum, in a minimally invasive manner. This study is designed to demonstrate the ability of MSts to exceed the current boundaries for transdermal delivery of compounds with different molecular weights, partition coefficients, acid dissociation constants, melting points, and water solubilities. In vitro permeation of a range of selected molecules, including acetyl salicylic acid (aspirin), galantamine, selegiline hydrochloride (Sel-HCl), insulin, caffeine, hydrocortisone (HC), hydrocortisone 21-hemisuccinate sodium salt (HC-HS) and bovine serum albumin (BSA) has been studied across excised porcine skin with and without poke and patch application of MSts. Permeation of the molecules was monitored using Franz diffusion cells over 24 h. MSts significantly increased the permeation of all selected molecules up to 40 times, compared to topical applications of the molecules without MSts. The greatest increase in permeation was observed for caffeine with 70 ± 8% permeation and the lowest enhancement was observed for HC with a 2.4 ± 1.3% increase in permeation. The highest obtained flux was BSA (8133 ± 1365 μg/cm2/h) and the lowest flux observed for HC (11 ± 4 μg/cm2/h). BSA and HC also showed the highest (16,275 ± 3078 μg) and the lowest (73 ± 47 μg) permeation amount after 24 h respectively. MSt-treated skin exhibits greatly increased permeation. The molecule parameters (size, acid dissociation constant, partition coefficient and solubility)—traditional hurdles associated with passive diffusion through intact skin—are overcome using MSt skin treatment.

Effect of Combined Electroacupuncture and Selegiline Treatment in Alzheimer's Disease: An Animal Model.

The complexity of pathological mechanisms in Alzheimer’s disease (AD) poses significant challenges to the development of corresponding drugs. Symptom-specific pharmacological interventions and alternative treatments provide promising treatment possibilities. Therefore, we considered a combination of selegiline (SEL) and electroacupuncture (EA). We used an animal model with AD to investigate the effect of a combination of these treatments on cognitive function. 5XFAD mice received a week of SEL treatment and 2 weeks of EA. Novel object recognition and Y-maze tests were subsequently performed to assess their cognitive functions. To determine the molecular action of the combination treatment, Western blots, Aβ1-42 enzyme-linked immunosorbent assays (ELISA), and micro-positron-emission tomography were also performed to assess pathological markers and processes. The results were assessed based on the difference between untreated transgenic, SEL-treated, and SEL- and EA-treated groups of mice. Mice in the combined treatment group demonstrated significantly better cognitive functions, and lesser neuroinflammation than the comparative groups. In addition, mice treated with a combination of SEL and EA did not demonstrate a direct modulation of insoluble Aβ but demonstrated greater glucose metabolism. Our findings demonstrated that SEL combined with EA treatment was associated with better cognitive functioning due to inhibition of neuroinflammation and increased glucose metabolism relative to the comparative groups in a mouse model with AD.

Effectiveness of Selegiline Hydrochlorate in Treating Neurosensory Disorders of the Lower Alveolar Nerve Resulting From Mandibular Sagittal Osteotomy: Preliminary Study.

Peripheral nerves transmit nerve signals between periphery and the spinal cord or brain stem. Its function can be compromised by trauma to the nerve, such as those that occur in surgical procedures such as orthognathic surgery. Depending on the type of injury, treatment may be proposed, but this is still a controversial point in literature. Alternative methods that assist in the treatment of paresthesia should be studied, and in this context, selegiline hydrochloride seems to be a promising drug. Based on the above, the aim of this study was to evaluate the effectiveness of selegiline hydrochloride in the treatment of facial sensory changes resulting from nerve injuries in patients undergoing maxillary orthognathic surgery. This was a double-blind randomized clinical trial with the voluntary participation of individuals who underwent orthognathic surgery. The facial sensitivity of these patients was evaluated by 2-point discrimination tests and directional perception in the region related to the lower alveolar nerve. Tests were comparatively applied at times T0 (before surgery), T8 (8 days after surgery), T15 (15 days after surgery), T30 (30 days after surgery), T60 (60 days after surgery), and T90 (90 days after surgery). The mean age of patients was 31.14 years. With the comparative analysis of the 2-point static test on the chin, difference was observed between groups at times T15 (P = 0.007), T30 (P = 0.010), and T90 (P = 0.027) in the intergroup evaluation. Regarding results of the comparative analysis of the 2-point static test on the lip, difference was observed between groups at times T30 (P = 0.023), T60 (P < 0.001), and T90 (P = 0.005) in the intergroup evaluation. In the direction test on the chin, difference was observed between groups at times T30 (P = 0.015), T60 (P = 0.001), and T90 (P < 0.001) in the intergroup evaluation. Selegiline hydrochloride has shown promising results in the treatment of neurosensory disorders resulting from maxillary orthognathic surgery.

Physiologically Based Pharmacokinetic Modeling of Transdermal Selegiline and Its Metabolites for the Evaluation of Disposition Differences between Healthy and Special Populations.

A physiologically based pharmacokinetic (PBPK) model of selegiline (SEL), and its metabolites, was developed in silico to evaluate the disposition differences between healthy and special populations. SEL is metabolized to methamphetamine (MAP) and desmethyl selegiline (DMS) by several CYP enzymes. CYP2D6 metabolizes the conversion of MAP to amphetamine (AMP), while CYP2B6 and CYP3A4 predominantly mediate the conversion of DMS to AMP. The overall prediction error in simulated PK, using the developed PBPK model, was within 0.5–1.5-fold after intravenous and transdermal dosing in healthy and elderly populations. Simulation results generated in the special populations demonstrated that a decrease in cardiac output is a potential covariate that affects the SEL exposure in renally impaired (RI) and hepatic impaired (HI) subjects. A decrease in CYP2D6 levels increased the systemic exposure of MAP. DMS exposure increased due to a reduction in the abundance of CYP2B6 and CYP3A4 in RI and HI subjects. In addition, an increase in the exposure of the primary metabolites decreased the exposure of AMP. No significant difference between the adult and adolescent populations, in terms of PK, were observed. The current PBPK model predictions indicate that subjects with HI or RI may require closer clinical monitoring to identify any untoward effects associated with the administration of transdermal SEL patch.

Ameliorative effect of selegiline in high fat diet induced obesity rat model: Possible role of dopaminergic pathway

ObjectivesDopamine a neurotransmitter plays an important role in food regulation. Various reports revealed that suppression of dopamine results in pathological overeating. Monoamine oxidase type B (MAO-B) inhibitor selegiline (SG) increases the level of dopamine in the brain. Thus, the current study was designed to examine whether selegiline (SG) could attenuate the development of experimental obesity and to explore the possible involvement of dopamine in high fat diet (HFD) induced obesity. Materials and methodsCurrent study illustrates importance of administrating SG (10 and 20 mg kg−1 day−1, p. o.) alone and SG (20 mg kg−1 day−1, p. o) in combination with chlorpromazine (CPZ) (6 mg kg−1 day−1p.o) in obesity. The SG and its combination with CPZ were given orally for 6 weeks along with high fat diet to the obese rats. The body weight, feed intake (Kcal), weight and size of fat pads, levels of serum glucose, triglycerides (TG), total cholesterol (TC), low density lipoprotein (LDL), very low-density lipoprotein VLDL and high density lipoproteins (HDL) were estimated as parameters of obesity. ResultsOral administration of SG (10 and 20 mg kg−1day−1) significantly reduced (p < 0.05) body weight gain, feed intake (Kcal), weight and size of fat pads, levels of serum glucose, TG, TC, LDL, VLDL in obese rats. Furthermore, Dopaminergic antagonist CPZ in combination with SG declines the beneficial effects of SG in obese rats. ConclusionThe present study demonstrates the involvement of dopaminergic pathway and beneficial effects of dopamine enhancer SG in HFD induced obesity.

Biopharmaceutical Potential of Selegiline Loaded Chitosan Nanoparticles in the Management of Parkinson's Disease.

Selegiline hydrochloride, a hydrophilic anti-Parkinson' moiety, undergoes extensive first-pass metabolism and has low bioavailability. A process to obtain of selegiline (SH) loaded chitosan nanoparticles was attempted to circumvent the above problem, through intranasal delivery. SH loaded polymeric nanoparticles were prepared by ionic gelation of chitosan with tripolyphosphate, and stabilized by tween 80/ poloxamer 188. The resulting nanoparticles (NPs) were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, entrapment efficiency, particle size, zeta potential and surface morphology by scanning electron microscopy. Further, they were schematically evaluated for mucoadhesive strength, in-vitro drug release, release kinetics, pharmacokinetics, catalepsy, akinesia, in-vivo lipid peroxidation, nitrite levels, glutathione, catalase enzyme levels in brain and physicochemical stability parameters. Selegiline nanoparticles (SP18) produced were in size of 63.1 nm, polydispersity index of 0.201, zeta potential of +35.2 mV, mucoadhesion of 65.4% and entrapment efficiency of 74.77%. Selegiline showed biphasic release from nanoparticles, over a period of 36 h, with Fickian diffusion controlled release profile. Maximum concentration of SH in plasma was recognized as 52.71 ng/ml at 2 h for SP18, 20.09 ng/ml at 1 h for marketed formulation, and 21.69 ng/ ml for drug solution. SH loaded NPs showed a reversive effect in catalepsy and akinesia behaviour. This effect was especially pronounced in rats receiving SH loaded CS-NPs. Significant decrease in lipid peroxidation and nitrite concentration; increase in reduced glutathione and catalase enzyme levels were obtained due to antioxidant characteristics of SH, which turned to be useful to treat Parkinson's disease. Selegiline loaded chitosan nanoparticles form an effective non-invasive drug delivery system of direct nose to brain targeting in Parkinson's disease.

Synthetic enhancer compounds, besides acting on biogenic amine system, influence the glutamate transmission and stress response

Pharmaceutically available enhancer selegiline/(-)-deprenyl (DEP) in the clinically used dose shows antidepressant effect, but nothing is known about this effect in enhancer dose, and its effect on co-morbid anxiety. Moreover, data about the antidepressant/antianxiety effects of the serotonin-influencing enhancer, (2R)-1-(1-benzofuran-2-yl)-N-propylpentane-2-amine (BPAP) are also missing. The aim of the present paper is to establish the role of enhancer regulation in anxiety and follow the changes in the phosphorylation of glutamate subunits in prefrontal cortex as well as stress-related organ and hormonal changes as possible background mechanism. The effect of 3-week-treatment of rats with specific (0.001 mg/kg for DEP, 0.0001 mg/kg for BPAP) and non-specific (0.1 mg/kg for DEP, 0.05 mg/kg for BPAP) enhancer doses were evaluated on anxiety-like behavior in the elevated plus maze (EPM) and open-field (OF) tests. Phosphorylated glutamatergic GluR1 and GluN2B subunits were analyzed by Western blot. Changes in the stress-regulatory system were evaluated by measuring the organ weights and blood corticosterone concentrations. Non-specific enhancer doses had a tendency for anxiolysis on EPM, while only 0.1 mg/kg DEP elevated motility in OF. Specific enhancer doses significantly increased the expression of both glutamatergic receptor subunits; non-specific doses elevated only pGluR1. Treatments had no effects on stress-like organ weights; however, the specific enhancer doses significantly reduced the dark phase resting corticosterone levels. The study proved the enhancer-sensitivity of the glutamatergic transmitter system and suggested enhancer-induced stabilization of stress-hormone levels without major impact on non-stimulated anxiety-like behavior.

Computational Insight into the Mechanism of the Irreversible Inhibition of Monoamine Oxidase Enzymes by the Antiparkinsonian Propargylamine Inhibitors Rasagiline and Selegiline.

Monoamine oxidases (MAOs) are flavin adenine dinucleotide containing flavoenzymes that catalyze the degradation of a range of brain neurotransmitters, whose imbalance is extensively linked with the pathology of various neurological disorders. This is why MAOs have been the central pharmacological targets in treating neurodegeneration for more than 60 years. Still, despite this practical importance, the precise chemical mechanisms underlying the irreversible inhibition of the MAO B isoform with clinical drugs rasagiline (RAS) and selegiline (SEL) remained unknown. Here we employed a combination of MD simulations, MM-GBSA binding free energy evaluations, and QM cluster calculations to show the MAO inactivation proceeds in three steps, where, in the rate-limiting first step, FAD utilizes its N5 atom to abstracts a hydride anion from the inhibitor α-CH2 group to ultimately give the final inhibitor-FAD adduct matching crystallographic data. The obtained free energy profiles reveal a lower activation energy for SEL by 1.2 kcal mol-1 and a higher reaction exergonicity by 0.8 kcal mol-1, with the former being in excellent agreement with experimental ΔΔG‡EXP = 1.7 kcal mol-1, thus rationalizing its higher in vivo reactivity over RAS. The calculated ΔGBIND energies confirm SEL binds better due to its bigger size and flexibility allowing it to optimize hydrophobic C-H···π and π···π interactions with residues throughout both of enzyme's cavities, particularly with FAD, Gln206 and four active site tyrosines, thus overcoming a larger ability of RAS to form hydrogen bonds that only position it in less reactive orientations for the hydride abstraction. Offered results elucidate structural determinants affecting the affinity and rates of the inhibition reaction that should be considered to cooperate when designing more effective compounds devoid of untoward effects, which are of utmost significance and urgency with the growing prevalence of brain diseases.

Development and Characterization of Nasal Delivery of Selegiline Hydrochloride Loaded Nanolipid Carriers for the Management of Parkinson's Disease.

Parkinson's Disease (PD) is one of the most common age-related neurodegenerative disorders which is marked with the loss of dopaminergic neurons. The present study performed on the nose to brain delivery of selegiline hydrochloride loaded nano lipid carrier, suggests that the nasal route is a good mean of targeting the drug directly into the brain. Nanostructured lipid carriers were prepared by using hot homogenization. Selegiline hydrochloride loaded NLCs and rotenone treatment were given at a dose of 10 mg/kg administered from 14th day to 28th day. Behavioral parameters were determined at 7th, 14th, 21st and 28th day. On the 28th day, animals were sacrificed for biochemical estimation. The optimized drug loaded NLC formulation has shown 93±5.25% entrapment efficiency and 51.96% loading capacity. Optimized NLCs formulation has shown 70% release within 10 hours and after that, the release of the drug is sustained up to 22 hours (97%). Pharmacological action of the drug was found to restore the behavioral parameters in rotenone-induced rats. Nano Lipid Carrier (NLCs) therapeutics has emerged as a prominent method for the treatment of Parkinson's Disease (PD) as it offers targeted delivery and enhances the therapeutic efficacy of neurotherapeutics. It is concluded from the studies that, Selegiline HCl loaded nano lipid carrier which was administered through nasal route has the potential to be used in the management therapy of Parkinson's disease.

Pharmacokinetics of selegiline, R-methamphetamine, R-amphetamine, and desmethylselegiline in oral fluid after a single oral administration of selegiline.

Chiral analysis is a crucial way to differentiate selegiline (SG) intake from drug abuse. Oral fluid (OF) has been successfully used as an alternative matrix for blood testing in several pharmacokinetic studies. The aim of this study is to describe the pharmacokinetics of SG and its main metabolites in OF after a single oral administration of SG which is meaningful for results interpretation in forensic analysis. Ten milligrams of SG were orally administered to 8 volunteers, and OF samples were collected for up to 96hours by having participants spit into polypropylene tubes without stimulation. These samples were submitted to liquid-liquid extraction before analysis by liquid chromatography-tandem mass spectrometry operating in positive ion multiple-reaction monitoring mode. After oral administration, each analyte could be detected in OF specimens from all volunteers with an initial detection time of 0.50hours. The Cmax values of SG, R-MA, R-AM and DM-SG were 50.93-992.67ng/mL, 29.78-653.64ng/mL, 8.22-150.15ng/mL, and 4.34-16.25ng/mL, respectively, at 0.5hours, 1-11hours, 1.5-11hours, and 0.5-6hours post dose. The times when the compounds were last determined in OF were 5-24hours for SG, 52-96hours for R-MA, 31-96hours for R-AM, and 13-31hours for DM-SG after oral administration. There is a period of time in OF in which only MA and AM are present without SG and DM-SG after a single dose of SG. The pharmacokinetic data could provide supplementary interpretation for OF tests in forensic science and drug treatment programs.

Dansyl azide as a selective fluorescence tagging probe for click chemistry reactions and its application to monitor rasagiline in pharmacokinetic studies

Click chemistry has been widely used for bioorthogonal labeling of biomolecules for its high efficiency, regioselectivity and biocompatibility. In this study, dansyl azide (DNS-AZ) was introduced as a novel fluorescence labeling reagent for the determination of alkynes based on copper (I)-catalyzed azide alkyne cycloaddition (CuAAC) click chemistry reaction. Rasagiline mesylate (RSM) is an irreversible, selective monoamine oxidase B (MAO-B) inhibitor. It is used as a model example for drugs with terminal alkyne moiety that could be monitored in biological samples with CuAAC reaction. RSM reacts with DNS-AZ in the presence of copper (II) and sodium ascorbate as catalysts to form stable 1,2,3-triazole derivative determined by HPLC with fluorescence detection. The developed methodology was optimized for sensitive and selective determination of RSM in rat plasma. Selegiline (SLG) was used as internal standard. The developed method was validated according to US-FDA guidelines in order to confirm method suitability for the intended application. The method allowed accurate and precise determination of RSM in the linearity range 0.50–100 ng mL−1 with a detection limit of 0.16 ng mL−1 for RSM in rat plasma. To confirm method applicability in real sample analysis, the developed method was employed to quantify RSM in a pharmacokinetic study in rats after administration of a single oral dose of RSM tablet.

Simultaneous determination of selegiline, desmethylselegiline, R/S-methamphetamine, and R/S-amphetamine in oral fluid by LC/MS/MS

It is crucial for forensic analysis to differentiate clinical use from illegal abuse. Selegiline (SG) is mainly metabolized to desmethylselegiline (DM-SG), R-(−)-methamphetamine (R-MA) and R-(−)amphetamine (R-AM); while abused methamphetamine and amphetamine mainly contain the S-(+)-form. The aim of this study was to simultaneously determine SG, DM-SG, R/S-MA, and R/S-AM in human oral fluid (OF) and to differentiate clinical use from illegal use. We also aim to apply the present method to the OF samples from authentic cases in forensic toxicology. Liquid–liquid extraction and liquid chromatography-tandem mass spectrometry operating in positive ion multiple-reaction monitoring mode were utilized. The chromatographic system consisted of a ChirobioticTM V2 column (2.1 mm × 250 mm, 5 μm) and a mobile phase of methanol containing 0.1% (v/v) glacial acetic acid and 0.02% (v/v) ammonium hydroxide. The calibration curves were linear from 1 to 100 ng/mL, and r > 0.995 for all analytes with imprecisions ≤ 15% and accuracy between 85 and 115%. Extraction recoveries ranged from 46.3 to 104.7% with coefficient of variation (CV) ≤ 10.3% and matrix effects (MEs) ranged from 47.4 to 114.8% with CV ≤ 12.9%. The lower limit of quantification was 0.2 ng/mL for SG and DM-SG and 1.0 ng/mL for S-MA, R-MA, S-AM and R-AM. The present method is simple, rapid (accomplished in 12 min), sensitive, and validated by authentic samples.