Analysis of methylphenidate, ethylphenidate, lisdexamfetamine, and amphetamine in oral fluid by liquid chromatography-tandem mass spectrometry.

Oral fluid is an alternative matrix that has proven to be useful for the detection of drugs. Oral fluid is easy to collect, noninvasive, and may indicate recent drug use. There are limited methods available that analyze cognitive stimulants in oral fluid. Cognitive stimulants are used to treat attention-deficit/hyperactivity disorder (ADHD), a neurological disorder that emerges from lack of dopamine in the brain. To combat this disorder, medications inhibit dopamine and norepinephrine reuptake by blocking transporters in the brain. Though commonly diagnosed in children, ADHD may extend beyond adolescence and abuse of medications in college students is not uncommon. The goal of this study was to develop and validate a quantitative method for methylphenidate, ethylphenidate, lisdexamfetamine, and amphetamine in oral fluid using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Analytes were isolated by solid-phase extraction and analyzed on an Agilent 1290 Infinity II Liquid Chromatograph coupled to an Agilent 6470 Triple Quadrupole Mass Spectrometer. The linear range was 0.5-100 ng/ml (except lisdexamfetamine at 5-500 ng/ml). Bias and between-run precision were acceptable (±11.0% bias and ±12.2%CV). No interferences or carryover were observed and dilution integrity was sustained. This validated method was applied to four authentic oral fluid samples collected with Quantisal® devices from college students. Lisdexamfetamine was quantified in one sample at 5.8 ng/ml while amphetamine was quantified in all four samples at 6.0-78.8 ng/ml. This is the first known quantitative method in oral fluid that includes these analytes using LC-MS/MS and may give rise to interpretive value in a forensic toxicology setting.

Assessment of lisdexamfetamine dimesylate stability and identification of its degradation product by NMR spectroscopy.

Lisdexamfetamine dimesylate (LDX), a long-acting prodrug stimulant indicated for the treatment of the attention-deficit/hyperactivity disorder (ADHD), was subjected to forced degradation studies by acid and alkaline hydrolysis and the degradation profile was studied. To obtain between 10-30% of degraded product, acid and alkaline conditions were assessed with solutions of 0.01 M, 0.1 M, 0.5 M, and 1 M of DCl and NaOD. These solutions were analyzed through 1 H NMR spectra. Acid hydrolysis produced no degradation in 0.01 M and 0.1 M DCl and 4.38%, 9.69%, and 17.75% of degradation LDX, respectively, in 0.5 M, 1 M (4h) and 1 M (4 + 12 h) DCl. And alkaline hydrolysis produced no degradation in 0.01 M and 0.1 M DCl and a degradation LDX extension of 8.5%, 14.30%, and 22.91%, respectively, in 0.5 M, 1 M (4h) and 1 M (4 + 12 h) NaOD. LDX solutions subjected to 1 M (4 + 12 h) acid and alkaline hydrolysis were evaluated by NMR spectra (1 H NMR, 13 C NMR, HSQC and HMBC). LDX degradation product (DP) was identified and its structure elucidated as a diastereoisomer of LDX: (2R)-2,6-diamino-N-[(2S)-1-phenylpropan-2-yl] hexanamide without their physical separation.

Identification, Characterization and Quantification of Process-Related and Degradation Impurities in Lisdexamfetamine Dimesylate: Identifiction of Two New Compounds.

Twelve impurities (process-related and degradation) in lisdexamfetamine dimesylate (LDX), a central nervous system (CNS) stimulant drug, were first separated and quantified by high-performance liquid chromatography (HPLC) and then identified by liquid chromatography mass spectrometry (LC-MS). The structures of the twelve impurities were further confirmed and characterized by IR, HRMS and NMR analyses. Based on the characterization data, two previously unknown impurities formed during the process development and forced degradation were proposed to be (2S)-2,6-di-(lysyl)-amino-N-[(1S)-1-methyl-2-phenyl ethyl]hexanamide (Imp-H) and (2S)-2,6-diamino-N-[(1S)-1-methyl-2-(2-hydroxyphenyl)ethyl] hexanamide (Imp-M). Furthermore, these two compounds are new. Probable mechanisms for the formation of the twelve impurities were discussed based on the synthesis route of LDX. Superior separation was achieved on a YMC-Pack ODS-AQ S5 120A silica column (250 × 4.6 mm × 5 µm) using a gradient of a mixture of acetonitrile and 0.1% aqueous methanesulfonic acid solution. The HPLC method was optimized in order to separate, selectively detect, and quantify all the impurities. The full identification and characterization of these impurities should prove useful for quality control in the manufacture of lisdexamfetamine dimesylate.

Chiral analysis of amphetamines in hair by liquid chromatography-tandem mass spectrometry: compliance-monitoring of attention deficit hyperactivity disorder (ADHD) patients under Elvanse® therapy and identification after controlled low-dose application.

Amphetamine (AMP) is used as an illicit drug and also for the treatment of attention deficit hyperactivity disorder (ADHD). Respective drugs most often contain the enantiomer (S)-AMP as active compound or (S)-AMP is formed from the prodrug lisdexamfetamine (Elvanse®) whereas the illicit drug is usually traded as racemate ((R/S)-AMP). A differentiation between the use of the medically prescribed drug and the abuse of illicit street amphetamine is of great importance, for example in retrospective consumption monitoring by hair analysis. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the chiral separation and quantitation of (S)- and (R)-AMP in hair was developed. For this purpose, 20 mg hair was extracted and derivatized with N-(2,4-dinitro-5-fluorophenyl)-L(S)-valinamide L(S)-(DNPV) to yield amphetamine diastereomers. Baseline separation of the resulting diastereomers was achieved on a high-pressure liquid-chromatography system (HPLC) coupled to a Sciex QTRAP® 5500 linear ion trap quadrupole mass spectrometer. The method was successfully validated. Analysis of hair samples from nine Elvanse® patients revealed only (S)-AMP in eight cases; one subject showed both enantiomers indicating a (side-) consumption of street amphetamine. The analysis of the 16 amphetamine users' samples showed only racemic amphetamine. Furthermore, it could be shown in a controlled study that (S)-AMP can be detected after administration of even very low doses of lisdexamfetamine and dexamphetamine, which can be of interest in forensic toxicology and especially in drug-facilitated crime (DFC). The method now enables the retrospective compliance-monitoring of ADHD patients and the differentiation between medically prescribed intake of (S)-amphetamine and abuse of illicit street amphetamine.

Method validation and determination of lisdexamfetamine and amphetamine in oral fluid, plasma and urine by LC-MS/MS.

Lisdexamfetamine (LDX) is a long-acting prodrug stimulant indicated for the treatment of attention-deficit/hyperactivity disorder and binge-eating disorder symptoms. In vivo hydrolysis of LDX amide bond releases the therapeutically active d-amphetamine (d-AMPH). Since toxicological tests in biological samples can detect AMPH from the use of some legal medications, efficient methods are needed in order to correctly interpret the results. The aim of this study was to develop and validate an LC-MS/MS method for the simultaneous quantification of LDX and its main biotransformation product AMPH in human oral fluid, plasma and urine. Calibration curve range for both analytes was 1-128 ng/mL in oral fluid and plasma and 4-256 ng/mL in urine, being the lowest concentration the limit of quantification. Accuracy of the determined values of the target analytes for the five control levels ranged from 94.8 to 111.7% for oral fluid, from 91.3 to 100.2% for plasma and from 94.8 to 109.8% for urine. Imprecision for the five control levels did not exceeded 12.8% for oral fluid, 16.2% for plasma and 17.1% for urine. The method developed for the three matrices was validated and was also successfully applied to assess real samples, showing for the first time the detection of LDX in oral fluid.