Targeted screening and quantification of synthetic cathinones and metabolites in hair by UHPLC-HRMS

OBJECTIVE

Synthetic cathinones (SCs) are new psychoactive substances with sympathomimetic effects, which emerged into the illegal drug market to replace controlled stimulants. Since every year more powerful and toxic substances enter the illicit market, there is the need for analytical methodologies able to detect these new compounds in conventional and non-conventional biological matrices. We sought to develop and validate a targeted screening and quantification method for thirty-two parent SCs and two metabolites in hair samples by ultra-high-performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-HRMS).

MATERIALS AND METHODS

20 mg hair samples were soaked in 250 µL of 2 mM ammonium formate, methanol and acetonitrile mixture (50/25/25, v/v/v) and incubated overnight at 40°C. After incubation, the samples were evaporated to dryness under nitrogen stream and reconstituted with 100 µL of mobile phase mix (A:B, 80:20) and 10 µL were injected into UHPLC-HRMS. A Q ExactiveTM Focus Orbitrap Mass spectrometer with full scan and targeted data-dependent MS/MS scan acquisition was used for the screening and quantitation analysis.

RESULTS

The assay was linear from 5 to 500 pg/mg hair for all the analytes under investigation. Intra-day and inter-day precision were always < 15% and matrix effect and analytical recovery were always within acceptable criteria (±25% and >50%, respectively). The developed method was applied to authentic hair samples from SCs consumers. The most prevalent found SCs were 3,4-Methylenedioxy-α-Pyrrolidinohexanophenone with a concentration range of 6.0-1,000.0 pg/mg along with α-Pyrrolidinohexiophenone (54.0 and 554.0 pg/mg, respectively), 3-Methylmetcathinone (556.0 and 5,000.0 pg/mg) and 4-Methylethcathinone (11.5 and 448.0 pg/mg) CONCLUSIONS: The developed method showed good selectivity, specificity, an easy and low-cost sample preparation and an analysis time compatible with a high throughput laboratory.

On-site screening and GC-MS analysis of cocaine and heroin metabolites in body-packers urine

The illicit transportation of cocaine and heroin either swallowed or inserted into the rectum and/or vagina of individuals, defined as "body-packers", is becoming increasingly common. Assessment of smuggling by urinalysis from body-packers has been sparsely reported and on-site rapid screening methods are essentially lacking. We screened the presence of cocaine and heroin metabolites in urine from suspected body-packers by an on-site immunochromatographic test and confirmed the obtained results by gas chromatography-mass spectrometry and X-ray examination. Samples were collected from 64 individuals (45 men, 19 women) stopped at Fiumicino and Ciampino airports of Rome (Italy) for suspicion of internal concealment of cocaine and heroin between October 2006 and July 2007. Urine was immediately screened on-site by Cozart rapid urine test. Irrespective of test results, individuals underwent X-ray examination and urine samples were analyzed by gas chromatography-mass spectrometry (GC-MS). In 48 out of 64 cases (24 positives and 24 negatives) screening results were confirmed by GC-MS assay and X-ray examination. In 5 cases, positive to the on-site test and GC-MS analysis, abdominal radiography was negative and individuals resulted to be drug users. In 11 cases, negative to the on-site test and radiological investigation, GC-MS analysis found benzoylecgonine in 10 cases and morphine in one case. Concentration of both substances was in all cases lower than 50ng/ml and compatible with personal drug use. From obtained results, on-site detection of cocaine and heroin metabolites in the urine of suspected body-packers appears to be a reliable screening test to disclose internally concealed drugs and justify subsequent radiological investigations.

Application of a validated high-performance liquid chromatography–mass spectrometry assay to the analysis of - and -hydroxybenzoylecgonine in meconium

A high-performance liquid chromatography (HPLC)-mass spectrometry (MS) assay, already validated for opiates and cocaine in meconium, has been re-applied for determination of m- and p-hydroxybenzoylecgonine, using nalorphine as the internal standard. Methodology included an initial extraction from the matrix by methanol and then a solid-phase extraction (SPE). A reversed-phase chromatography was used with a gradient of 1% acetic acid-acetonitrile coupled to atmospheric pressure ionization electrospray-mass spectrometry single ion monitoring mode. This method, validated in the range 0.005-1.00 microg analytes/g meconium, proved useful to identify and quantify these two metabolites in meconium samples, already tested for the presence of cocaine, benzoylecgonine and cocaethylene. A positivity of range of concentrations varied between 0.007 and 0.338 microg/g, confirming the importance of these two hydroxylated derivatives to monitor fetal exposure to cocaine.

New vesicular ampicillin-loaded delivery systems for topical application: characterization, in vitro permeation experiments and antimicrobial activity

In this paper, the experimental conditions for preparing ampicillin-loaded surfactant vesicles (SVs) are described. Our studies are focused on the potential use of a vesicular polymeric dispersion as ampicillin delivery system for topical application. The main components of the formulation are uncharged and charged SVs loaded with ampicillin and dispersed in a gellan solution. The following issues are addressed: the drug encapsulation efficiency (e.e.), the kinetic of drug release from the delivery systems, the antimicrobial activity of vesicle-entrapped ampicillin. The in vitro permeation experiments through a synthetic lipophilic barrier (Silastic) and through porcine skin are carried out to evaluate the potential use as a dermal formulation. The use of both a synthetic and a biological membrane allows to discriminate between the effects related to variations of thermodynamic parameters and those correlated to biological factors. The release rate of ampicillin is increased by encapsulation in neutral and negatively charged SVs and the permeation rate was slowed by dispersion of drug-loaded SVs in gellan solution. Finally, studies of antimicrobial activity on prepared systems evidenced that ampicillin encapsulated in SVs exhibit a higher activity than the free drug.

Development and validation of a liquid chromatography-mass spectrometry assay for the determination of opiates and cocaine in meconium

A procedure based on liquid chromatography-mass spectrometry (LC-MS) is described for determination of 6-monoacetylmorphine, morphine, morphine-3-glucuronide, morphine-6-glucuronide, codeine, cocaine, benzoylecgonine and cocaethylene in meconium using nalorfine as the internal standard. The analytes are initially extracted from the matrix by methanol (6-monoacetylmorphine, morphine, codeine, cocaine, benzoylecgonine and cocaethylene) or 0.01 M ammonium hydrogen carbonate buffer (morphine-3-glucuronide, morphine-6-glucuronide). Subsequently a solid-phase extraction with Bondelut Certify columns (6-monoacetylmorphine, morphine, codeine, cocaine, benzoylecgonine and cocaethylene) or ethyl solid-phase extraction columns (morphine-3-glucuronide, morphine-6-glucuronide) was applied. Chromatography was performed on a C(8) reversed-phase column using a gradient of acetic acid 1%-acetonitrile as a mobile phase. Analytes were determined in LC-MS single ion monitoring mode with atmospheric pressure ionisation-electrospray (ESI) interface. The method was validated in the range 0.005-1.00 microg/g using 1 g of meconium per assay and applied to analysis of meconium in newborns to assess fetal exposure to opiates and cocaine.

Assay of gamma-glutamylcysteine synthetase activity in Plasmodium berghei by liquid chromatography with electrochemical detection

This work describes a high-performance liquid chromatography (HPLC) method to determine gamma-glutamylcysteine (gamma-GC), the intermediate product of glutathione biosynthesis. Separation relies on isocratic reversed-phase chromatography using a Symmetry C18 HPLC column, particle size 5 microm, 4.6 x 250 mm i.d. The mobile phase is methanol-dibasic sodium phosphate (pH 6.6; 2.8 mM) (10:90, v/v) at the flow-rate of 0.5 ml/min and detection is operated electrochemically (+200 and +550 mV) with a pre-column derivatisation reaction using ortho-phthalaldehyde (OPA) as reagent. Under these conditions the calibration range of gamma-GC was 0.3-10 microg/ml; the limit of quantification was 0.3 microg/ml; accuracy, expressed as %Bias, was <10 and precision (%CV) was <6. The proposed HPLC assay was used to quantitate the gamma-glutamylcysteine produced by the gamma-glutamylcysteine synthetase of the rodent malaria parasite Plasmodium berghei in an in vitro enzymatic assay.

Morphological analysis of the interaction of charged surfactant vesicles (SVs) with human cultured cells

We analyzed the binding and fusogenic properties of surfactant vesicles (SVs), composed of ionic and nonionic surfactants and cholesterol, with the surface of different human lymphoid cells. The influence of charge on SVs-cell interaction was evaluated by monitoring the presence of fluorescent sodium calcein artificially entrapped in the vesicles using optical fluorescence microscopy and laser scanning confocal microscopy. Our results clearly indicate that only negatively charged vesicles bind and fuse with the plasma membrane of human lymphoid cells, and the number of SVs bound to the cell surface was variable among the positive cells. Thin section electron microscopy illustrated that the fusogenic events of SVs with the cell plasma membrane mostly occurred at smooth and nonvillous regions of the cell surface. Taken together, our results suggest that binding and fusion of SVs with the cell plasma membrane might be dependent on interactions with specific membrane components that preferentially recognize negatively charged SVs.