Methylephedrine concentrations in blood and urine specimens

A randomized placebo controlled trial demonstrates the effect of dl-methylephedrine on brain functions is weaker than that of pseudoephedrine

Intellectual drug doping in athletics by using stimulants that affect central nervous system functions has been diversified. Stimulants are regulated by the World Anti-Doping Agency according to their levels of urinary concentration. Positron emission tomography could evaluate how stimulants affect central nervous system functions. We aimed to evaluate the effect of stimulants on brain function by examining the difference in brain dopamine transporter occupancy by PET after administration of dl-methylephedrine or pseudoephedrine at the clinical maximum daily dose. Four PET scans without and with drug administration (placebo, dl-methylephedrine 150 mg and pseudoephedrine 240 mg) were performed. The concentrations of dl-methylephedrine and pseudoephedrine in plasma and urine were measured. DAT occupancies in the striatum with placebo, dl-methylephedrine and pseudoephedrine were calculated by PET images. The urinary concentration of dl-methylephedrine (12.7 µg/mL) exceeded the prohibited concentration (10 µg/mL), but the DAT occupancy with dl-methylephedrine (6.1%) did not differ (p = 0.92) from that with placebo (6.2%). By contrast, although the urinary concentration of pseudoephedrine (144.8 µg/mL) was below the prohibited concentration (150 μg/mL), DAT occupancy with pseudoephedrine was 18.4%, which was higher than that with placebo (p = 0.009). At the maximum clinical dose, dl-methylephedrine was shown to have weaker effects on brain function than pseudoephedrine.

Bioavailability of the Common Cold Medicines in Jellies for Oral Administration

Jellies for oral administration have been suggested as alternative dosage forms to conventional tablets for improved palatability and compliances for pediatric and geriatric patients. To evaluate the effect of jelly formulation on the bioavailability of cold medicines, two types of jellies were prepared for a fixed-dose combination of acetaminophen (AAP), chlorpheniramine maleate (CPM), dextromethorphan hydrobromide (DMH), and dl-methylephedrine hydrochloride (MEH). Jelly-S and Jelly-H were fabricated using carrageenan and locust bean gum in the absence and presence of xanthan gum, respectively. In vitro dissolution and in vivo absorption of the four drugs in the jellies were compared with other conventional formulations, a syrup and two types of immediate-release (IR) tablets with different hardness, Tablet-S (15 kPa) and Tablet-H (20 kPa). All the formulations exhibited more than 80% dissolution rate within 2 h even though the syrup, Jelly-S, and Tablet-S showed higher 30-min dissolution compared to Jelly-H and Tablet-H. The dissolution rates from the jellies decreased with increasing pH, which resulted in the slowest dissolution in pH 6.8 compared to the syrup and IR tablets. When administered orally to beagle dogs, all five formulations were determined not to be bioequivalent. However, Jelly-S and Jelly-H showed 0.82-1.05 of the geometric mean ratios (GMRs) of AUC_0-t for all four drugs compared to the syrup suggesting comparable absorption. In two IR tablets, GMRs of AUC_0-t were in a range of 0.55-0.95 indicating a tendency of lower absorption than the syrup and jellies. In conclusion, jelly can be a patient-centered formulation with comparable bioavailability to syrup.

Interconversion of ephedrine and pseudoephedrine during chemical derivatization

Gas chromatography-mass spectrometry (GC-MS) analysis after heptafluorobutyric anhydride (HFBA) derivatization was one of the published methods used for the quantification of ephedrine (EP) and pseudoephedrine (PE) in urine. This method allows the clear separation of the derivatized diastereoisomers on a methyl-silicone-based column. Recently the authors came across a human urine sample with apparently high levels (µg/ml) of EP and PE upon initial screening. However, duplicate analyses of this sample using the HFBA-GC-MS method revealed an unusual discrepancy in the estimated levels of EP and PE, with the area response ratios of EP/PE at around 29% on one occasion and around 57% on another. The same sample was re-analyzed for EP and PE using other techniques, including GC-MS after trimethylsilylation and ultra-high-performance liquid chromatography-tandem mass spectrometry. Surprisingly, the concentration of EP in the sample was determined to be at least two orders of magnitude less than what was observed with the HFBA-GC-MS method. A thorough investigation was then conducted, and the results showed that both substances could interconvert during HFBA derivatization. Similar diastereoisomeric conversion was also observed using other fluorinated acylating agents (e.g. pentafluoropropionic anhydride and trifluoroacetic anhydride). The extent of interconversion was correlated with the degree of fluorination of the acylating agents, with HFBA giving the highest conversion. This conversion has never been reported before. A mechanism for the interconversion was proposed. These findings indicated that fluorinated acylating agents should not be used for the unequivocal identification or quantification of EP and PE as the results obtained can be erroneous.

Qualitative confirmation procedure for ephedrines as acetonide derivatives in doping urine samples by gas chromatography/electron ionization mass spectrometry

Ephedrines are sympathomimetic amines which have central nervous system stimulating properties and, for this reason, some of them are forbidden in sport by the World Antidoping Agency (WADA). They are screened and quantitated in urine by several published techniques and confirmed by gas chromatography/mass spectrometry (GC/MS). In this paper, a simple and easy confirmation procedure for norpseudoephedrine, norephedrine, ephedrine and pseudoephedrine in human urine by GC/electron ionization (EI)-MS is described. After the addition of diphenylamine as internal standard, a liquid-liquid extraction procedure under alkaline conditions with tert-butyl methyl ether was applied to the samples. The analytes were derivatized with acetone and pyridine to form the correspondent oxazolidine derivatives (acetonide). The EI mass spectra of all the studied substances have many diagnostic ions with relative abundance in accordance with WADA requirements and show great structural information content. The fragmentation of theses derivatives is discussed.

Metabolites of ephedrines in human urine after administration of a single therapeutic dose

Ephedrine (EPH), pseudoephedrine (PEPH), phenylpropanolamine (PPA), methylephedrine (MEPH) and cathine are sympathomimetic amines. These drugs are commonly found in over-the-counter (OTC) cold medicines and some dietary supplements. In Taiwan, the misuse of these drugs has resulted in an increase in athletic violations. Excretion studies of the ephedrine-related drugs have been performed to better understand the metabolic yields of ephedrines in urine. After consuming a single clinical dose of each of these drugs, urine samples from volunteers (n=3 for each drug) were subjected to tert-butyl-methyl-ether (TBME) extraction and trifluoroacetic acid (TFAA) derivatization before gas chromatography-mass spectrometry (GC-MS) analysis. Most ephedrines were excreted unchanged in urine, including EPH (40.9%), PEPH (72.2%), and PPA (59.3%). However, only a relatively small amount of MEPH (15.5%) was excreted unchanged in urine. In addition, a trace amount of PPA (1.6%) and cathine (0.7%) was found to be the metabolites of EPH and PEPH, respectively. Urinary EPH, PEPH, and PPA reached peaks at 2-6h and disappeared in urine at approximately 24-48 h post-administration. For MEPH, the peaks of excretion extended from 4 to 12h post-administration and were undetectable at approximately 48 h. A single clinical dose of EPH (25 mg) may exceed threshold level (10 microg/mL) in sport drug testing if the urine samples are tested within approximately 8h post-administration. However, a single dose of MEPH (20 mg) never reached the threshold value (10 microg/mL).

Methcathinone: A new postindustrial drug

Methcathinone, a methyl derivative of cathinone, is an illicit drug also known as ephedrone. It is a stimulant found in the "khat" plant, Catha edulis, which can easily be synthesized from pseudoephedrine. Its intoxication is difficult to diagnose and cure properly for two reasons: (i) target consumers are usually "well-educated people" aware of the risks and precautionary measures and (ii) intoxication by cathinone derivatives of synthetic or natural (derived from the khat) origin induce misleading symptoms. As a result, documented reports of methcathinone intoxication that are based on reliable analyses are rare. This paper describes a case of reiterated coma due to an overdose of methcathinone dissolved in alcohol that was taken with bromazepam. A 29-year-old woman was admitted to an emergency department for a coma of toxic origin. Medical files showed that it was her second such episode to occur that month. Moreover, the family indicated signs of depression, incoherent behaviour and intake of "amphetamine-like" drugs. Clinical examination revealed a Glasgow coma score of 9, symmetrical reactive pupils with mydriasis and no convulsions. The patient presented with rapid respirations and her blood pressure was 93/53 mmHg. The ionogram and the blood gas analyses were normal, while the blood alcohol level was 0.167 g/dL. Urinalysis revealed the presence of benzodiazepines and a high concentration of amphetamines (methcathinone: 17.24 mg/L, ephedrine: 11.60 mg/L and methylephedrine: 11.10 mg/L). In addition, serum analysis revealed bromazepam (8.89 mg/L), methcathinone (0.50 mg/L) and methylephedrine (0.19 mg/L). This case showed that the consumption of bromazepam and alcohol altered the typical clinical symptoms of cathinone derivative intoxication, namely hypertension and convulsions. Methylephedrine, an impurity resulting from the alkylation of a primary amine, can be considered a chemical tag indicating fraudulent synthetic origin of the drug. This case describes a documented example of new addictive behaviour of "well-educated" people involving the intake of methcathinone, a postindustrial psychostimulant intentionally combined with an anticonvulsant benzodiazepine. However, this specific case suggests that in spite of a very high bromazepam concentration in presence of the potentiator alcohol, the vital respiratory function would be probably maintained, thanks to the association with methcathinone.

Simultaneous determination of amphetamine and one of its metabolites by HPLC with electrochemical detection

A high-performance liquid chromatographic method coupled with electrochemical detector was developed for the separation and quantitation of amphetamine and one of its metabolites, the 4-hydroxynorephedrine. The pre-column derivatisation of these compounds was carried out with 2,5-dihydroxybenzaldehyde as electroactive labelling reagent, in presence of Borohydride Exchange Resin. The new synthetic method developed was fast, clean and high yielding. The analysis was performed in isocratic mode on a reversed phase column 5 microm Hypersil ODS RP-18, 15 cm, using as a mobile phase methanol-NaH(2)PO(4) buffer (50 mM, pH 5.5)(30:70 v/v) containing trietylamine (0.5% v/v) and the products were detected by a porous graphite electrode set at an oxidation potential of +0.6 V. The linearity of response was examined for each derivatised compound and was analysed using solutions in the range 10-40 nmol/ml. The correlation coefficients of the linear regression of the standard curves were greater than 0.99. The method developed in this study was sensitive and very selective. Because of the specificity for primary phenylethylamines, it could be applicable for the assay of other related substances in toxicology and drugs abuse.

Suspected caffeine and ephedrine toxicosis resulting from ingestion of an herbal supplement containing guarana and ma huang in dogs: 47 cases (1997-1999)

OBJECTIVE

To describe the clinical signs following ingestion of an herbal supplement containing guarana and ma huang in dogs, estimate minimum dose at which clinical signs of toxicosis and death were reported, and evaluate treatment options.

DESIGN

Retrospective study.

ANIMALS

47 dogs with evidence of ingestion of an herbal supplement containing primarily guarana and ma huang.

PROCEDURE

Records of dogs that had ingested an herbal supplement containing ma huang and guarana between July 1997 and October 1999 were retrieved from the National Animal Poison Control Center database. Data were retrieved and reviewed regarding signalment, dose ingested, clinical signs, laboratory test results, treatment, and final outcome. Cases were assessed by staff veterinarians as toxicosis or suspected toxicosis on the basis of strength of evidence supporting a diagnosis.

RESULTS

Most dogs (80%) developed clinical signs of toxicosis within 8 hours of ingestion, and clinical signs persisted for up to 48 hours. Hyperactivity, tremors, seizures, and behavior changes were reported in 83% of dogs; other signs included vomiting (47%), tachycardia (30%), and hyperthermia (28%). Seventeen percent of the dogs died or were euthanatized. Estimated doses of guarana and ma huang ranged from 4.4 to 296.2 mg/kg (1.98 to 133.2 mg/lb) and 1.3 to 88.9 mg/kg (0.58 to 40.0 mg/lb) of body weight, respectively; minimum dose at which death was reported was 19.1 mg of guarana/kg (8.7 mg/lb) and 5.8 mg of ma huang/kg (2.6 mg/lb).

CONCLUSIONS AND CLINICAL RELEVANCE

Accidental ingestion of herbal supplements containing primarily guarana and ma huang in dogs can lead to a potentially lethal condition that may require prompt detoxification and supportive treatment for several days. Most dogs recovered with supportive treatment.