Safety, Tolerability, and Pharmacokinetics of SUVN-G3031, a Novel Histamine-3 Receptor Inverse Agonist for the Treatment of Narcolepsy, in Healthy Human Subjects Following Single and Multiple Oral Doses.

Background And Objective: SUVN-G3031 is a novel, potent, and selective histamine-3 receptor (HR) inverse agonist in development for the treatment of narcolepsy. Our objective was to characterize the safety, tolerability, and pharmacokinetics of SUVN-G3031 in healthy young adults after single and multiple doses, and to evaluate the effect of food, gender, and age on the pharmacokinetics.

Methods: A single ascending dose (SAD) and a multiple ascending dose (MAD) study for 14 days was conducted in healthy young adults using a randomized, double-blind study design.

Safety, Tolerability and Pharmacokinetics of the Serotonin 5-HT6 Receptor Antagonist, SUVN-502, in Healthy Young Adults and Elderly Subjects.

Background And Objective: SUVN-502, a selective 5-HT6 receptor antagonist, was found to be active in preclinical models of cognitive deterioration suggesting a potential role in the treatment of dementia related to Alzheimer's disease. The objective of this study was to characterize the safety, tolerability and pharmacokinetics of SUVN-502 in healthy young adults and elderly subjects following single and multiple oral doses.

Methods: Single doses (5, 15, 50, 100 and 200 mg SUVN-502) and multiple doses (50, 100 and 130 mg SUVN-502 once daily for 7 days) were evaluated in healthy young adults and multiple doses (50 and 100 mg SUVN-502 once daily for 14 days) were evaluated in elderly subjects using randomized, double-blind, placebo-controlled, dose-escalating study designs.

Pharmacokinetic profiling of efavirenz-emtricitabine-tenofovir fixed dose combination in pregnant and non-pregnant rats.

During pregnancy, the disposition of various drugs is altered due to changes in physiological condition, maternal gastrointestinal absorption, gastric secretion and motility. A fixed dose combination of antiretrovirals is commonly prescribed for the treatment of HIV infection. There is a need to understand the pharmacokinetics and placental transfer of efavirenz-emtricitabine-tenofovir in fixed dose combination during pregnancy.

Simultaneous extraction of acetylsalicylic acid and salicylic acid from human plasma and simultaneous estimation by liquid chromatography and atmospheric pressure chemical ionization/tandem mass spectrometry detection. Application to a pharmacokinetic study.

A simple analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in atmospheric chemical ionization mode (APCI) for the simultaneous estimation of acetylsalicylic acid (ASA, CAS 50-78-2) and its active metabolite salicylic acid (SA, CAS 69-72-7) in human plasma has been developed and validated. ASA and SA were analyzed simultaneously despite differences in plasma concentration ranges of ASA and SA after oral administration of ASA. In spite of having different chemical, ionization and chromatographic properties, ASA and SA were extracted simultaneously from the plasma sample using acetonitrile protein precipitation followed by liquid-liquid extraction.

Liquid chromatography tandem mass spectrometry method for the quantification of sarpogrelate, a selective 5-HT(₂A) receptor antagonist, in plasma: application to a pre-clinical pharmacokinetic study.

A simple LC-MS/MS method was developed and validated for the estimation of sarpogrelate in 50 µL of rat plasma. The analyte and internal standard (IS) were extracted from rat plasma by acetonitrile precipitation and they were separated on a reversed-phase C₈ column with gradient program. The MS acquisition was performed with multiple reaction monitoring mode using m/z 430.

High-performance liquid chromatographic method for the separation of enantiomeric gatifloxacin.

A high-performance liquid chromatographic method has been developed in normal-phase conditions for the separation of enantiomeric gatifloxacin, (+/-) 1-cyclopropyl-6-fluoro-8-methoxy-7-(3-methylpiperazin-1-yl)-4-oxo-quinoline-3-carboxylic acid, an antibiotic in bulk drug. The method involved the use of an amylose-based Chiralpak AD-H (150 mm x 4.6 mm, 5 microm) column using a mobile phase system containing n-hexane-ethanol-diethylamine (85:15:0.

Quantification of acetylcholine, an essential neurotransmitter, in brain microdialysis samples by liquid chromatography mass spectrometry.

Chemical neurotransmission has been the subject of intensive investigations in recent years. Acetylcholine is an essential neurotransmitter in the central nervous system as it has an effect on alertness, memory and learning. Enzymatic hydrolysis of acetylcholine in the synaptic cleft is fast and quickly metabolizes to choline and acetate by acetylcholinesterase.

Liquid chromatography atmospheric pressure chemical ionization tandem mass spectrometry method for the quantification of pregabalin in human plasma.

A sensitive high-performance liquid chromatography positive ion atmospheric pressure chemical ionization tandem mass spectrometry method was developed and validated for the quantification of pregabalin in human plasma. Following liquid-liquid extraction, the analyte was separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M+H](+) ions, m/z 160-142 for pregabalin and m/z 482-258 for the internal standard. The assay exhibited a linear dynamic range of 1-10,000ng/mL for pregabalin in human plasma.

Liquid chromatography-tandem mass spectrometry method for the quantification of dimebon in rat plasma and brain tissue.

A sensitive high-performance liquid chromatography-positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of dimebon in rat plasma and brain tissue. Following liquid-liquid extraction, the analyte was separated using a gradient mobile phase on a reversed phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M+H](+) ions, m/z 320-277 for dimebon and m/z 407-100 for the internal standard. The assay exhibited a linear dynamic range of 0.

Sensitive liquid chromatography positive electrospray tandem mass spectrometry method for the quantitation of tegaserod in human plasma using liquid-liquid extraction.

A sensitive and rapid high-performance liquid chromatography-positive ion electrospray tandem mass spectrometry method is developed and validated for the quantitation of tegaserod in human plasma. Following liquid-liquid extraction, the analytes are separated using an isocratic mobile phase on a reversed-phase column and analyzed by tandem mass spectrometry in the multiple reaction monitoring mode using the respective (M+H)+ ions, m/z 302 to 173 for tegaserod and m/z 409 to 228 for the internal standard. The assay exhibits a linear dynamic range of 100-10000 pg/mL for tegaserod in human plasma.

A simple and rapid method to collect the cerebrospinal fluid of rats and its application for the assessment of drug penetration into the central nervous system.

Many central nervous system (CNS) drug discovery programs require the successful collection of cerebrospinal fluid (CSF) for assessing CNS penetration and distribution of new chemical entities. The objective of the present investigation was to simplify the technique for collecting maximum CSF from cisterna magna of the rats. Rat was anesthetized with 5% halothane and positioned in a stereotaxic frame.

Enantiomeric separation of Linezolid by chiral reversed-phase liquid chromatography.

A chiral liquid chromatographic method is developed for the enantiomeric resolution of Linezolid, (S)(-)-N-[[-3-(3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl] methyl] acetamide, an antibiotic in bulk drugs. The enantiomers of Linezolid are resolved on a Chiralcel OJ-RH column using a mobile phase system containing 150mM di-sodium hydrogen phosphate buffer (pH 4.5)-acetonitrile (86:14, v/v).

Simultaneous quantification of a non-nucleoside reverse transcriptase inhibitor efavirenz, a nucleoside reverse transcriptase inhibitor emtricitabine and a nucleotide reverse transcriptase inhibitor tenofovir in plasma by liquid chromatography positive ion electrospray tandem mass spectrometry.

A high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry method for the simultaneous quantification of efavirenz, emtricitabine and tenofovir was developed and validated with 100 microL human plasma. Following solid-phase extraction, the analytes were separated using a gradient mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M + H]+ ions, m/z 316 to 168 for efavirenz, m/z 248-130 for emtricitabine and m/z 288-176 for tenofovir, m/z 482-258 for rosuvastatin (IS), m/z 260-116 for propranolol (IS). The method exhibited a 100-fold linear dynamic range for all the three analytes in human plasma (20-2000, 2-200 and 20-2000 ng/mL for efavirenz, emtricitabine and tenofovir respectively).

Sensitive liquid chromatography tandem mass spectrometry method for the quantification of Quetiapine in plasma.

A sensitive high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of quetiapine in rat plasma. Following liquid-liquid extraction, the analyte was separated using a gradient mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M + H]+ ions, m/z 384 to m/z 221 for quetiapine and m/z 327 to m/z 270 for the internal standard. The assay exhibited a linear dynamic range of 0.

Liquid chromatography tandem mass spectrometry method for the quantification of amisulpride with LLOQ of 100 pg/mL using 100 microL of plasma.

A sensitive and selective high-performance liquid chromatography-positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of amisulpride in 100 microL of human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective (M + H)(+) ions, m/z 370-242 for amisulpride and m/z 341-112 for the internal standard. The assay exhibited a linear dynamic range with a lower range of 0.

Liquid chromatography tandem mass spectrometry method for the quantification of clonidine with LLOQ of 10 pg/mL in human plasma.

A sensitive high-performance liquid chromatography-positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of clonidine in human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M + H](+) ions, m/z 230 to 44 for clonidine and m/z 254 to 44 for the internal standard. The assay exhibited a linear dynamic range of 10-2000 pg/mL for clonidine in human plasma.

Liquid chromatography tandem mass spectrometry method for the quantification of rimonabant, a CB1 receptor antagonist, in human plasma.

A sensitive high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of rimonabant in human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective (M+H)+ ions, m/z 463-363 for rimonabant and m/z 408-235 for the internal standard. The assay exhibited a linear dynamic range of 0.

Sensitive liquid chromatography tandem mass spectrometry method for the quantification of sitagliptin, a DPP-4 inhibitor, in human plasma using liquid-liquid extraction.

A sensitive high-performance liquid chromatography-positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of sitagliptin, a DPP-4 inhibitor, in human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M + H](+) ions, m/z 408-235 for sitagliptin and m/z 310-148 for the internal standard. The assay exhibited a linear dynamic range of 0.

Rapid and simple liquid chromatography tandem mass spectrometry method for the quantification of zidovudine in rat plasma.

A high-performance liquid chromatography/electrospray ionization tandem mass spectrometry method was developed and validated for the quantification of zidovudine in rat plasma. Following solid-phase extraction, the analytes were separated using an isocratic mobile phase on a reverse phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M+H]+ ions, m/z 268/127 for zidovudine and m/z 230/112 for the internal standard. The method exhibited a linear dynamic range of 5-500 ng/mL for zidovudine in rat plasma.

Quantification of tenatoprazole in rat plasma by HPLC: validation and its application to pharmacokinetic studies.

A simple, reliable HPLC method with UV detection (295 nm) in rat plasma was developed and validated for quantification of tenatoprazole, a novel proton pump inhibitor, which is in clinical trials. Following a single-step liquid-liquid extraction, the analyte and internal standard were separated using an isocratic mobile phase on a reverse phase C(18) column. The lower limit of quantitation was 20 ng/mL, with a relative standard deviation of less than 10%.

Quantification of pramipexole in human plasma by liquid chromatography tandem mass spectrometry using tamsulosin as internal standard.

A high-performance liquid chromatography/electrospray ionization tandem mass spectrometry method was developed and validated for the quantification of pramipexole in human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M + H](+) ions, m/z 212/152 for pramipexole and m/z 409/228 for the IS. The method exhibited a linear dynamic range of 200-8000 pg/mL for pramipexole in human plasma.

Chromatography-mass spectrometry methods for the quantitation of statins in biological samples.

The 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase inhibitors, more commonly known as 'statins', are a novel class of drugs widely used for the treatment of hypercholesterolaemia in patients with established cardiovascular disease as well as those at high risk of developing atherosclerosis. Published chromatographic-mass spectrometric methods for the quantification of presently available seven statins, atorvastatin, simvastatin, lovastatin, pravastatin, fluvastatin, rosuvastatin and pitavastatin are reviewed. High performance liquid chromatography (HPLC) in combination with tandem mass spectrometry (MS/MS) is the analytical technique of choice for the quantification of statins in biological samples.

Quantitative determination of galantamine in human plasma by sensitive liquid chromatography-tandem mass spectrometry using loratadine as an internal standard.

A simple, rapid, sensitive, and selective liquid chromatography-tandem mass spectrometry method is developed and validated for the quantitation of galantamine, an acetylcholinesterase inhibitor in human plasma, using a commercially available compound, loratadine, as the internal standard. Following liquid-liquid extraction, the analytes are separated using an isocratic mobile phase on a reverse-phase C18 column and analyzed by mass spectrometry in the multiple reaction monitoring mode using the respective (M+H)+ ions, m/z 288 to 213 for galantamine and m/z 383 and 337 for the internal standard. The assay exhibit a linear dynamic range of 0.

Quantification of pseudoephedrine in human plasma by LC-MS/MS using mosapride as internal standard.

A simple, sensitive and rapid high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of pseudoephedrine in human plasma using mosapride as internal standard. Following solid-phase extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple-reaction monitoring mode using the respective [M + H](+) ions, m/z 166/148 for pseuoephedrine and m/z 422/198 for the IS. The method exhibited a linear dynamic range of 2-1000 ng/mL pseudoephedrine in human plasma.

Quantification of fexofenadine in human plasma by liquid chromatography coupled to electrospray tandem mass spectrometry using mosapride as internal standard.

A rapid high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of fexofenadine in human plasma using mosapride as internal standard. Following solid-phase extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M+H]+ ions, m/z 502/466 for fexofenadine and m/z 422/198 for the IS. The method exhibited a linear dynamic range of 1-500 ng/mL for fexofenadine in human plasma.