Antipsychotic and antiepileptic drugs in bipolar disorder: The importance of therapeutic drug monitoring

Bipolar disorder (BD) is a long-term illness with mood swings which are characterized by recurrent episodes of mania/hypomania and depression, with variable interpolations of relatively asymptomatic periods, called euthymic, in which, however, some psychopathological symptoms may persist. Although mood stabilizers, such as lithium, are the first-line treatment for the prevention of new BD episodes, combination therapy has become the standard of care for BD patients. Besides lithium, the use of a mood stabilizer along with an atypical antipsychotic is recommended in many patients. Recently, atypical antipsychotics (quetiapine, olanzapine, risperidone and aripiprazole) and antiepileptic agents (valproate, lamotrigine and oxcarbazepine) are increasingly used as mood stabilizers. To reduce side effects and optimize treatment it is important to perform accurate monitoring of drug blood levels in these patients, who are often treated with multiple drugs. Therapeutic drug monitoring (TDM) is in fact a powerful tool that, starting from clinical-chemical correlation data, allows to tailor-cut treatment to the specific needs of individual patients; hence the need to have reliable analytical methods available for the determination of plasma levels of drugs and their metabolites. Analyses of biological samples are mainly carried out using high-performance liquid chromatography (HPLC) coupled with different detectors, capillary electrophoresis and gas-chromatography. Various procedures are employed to remove biological interferences before analyzing the samples. This review focuses on currently available analytical TDM methods for atypical antipsychotics and antiepileptic agents used in the treatment of patients with bipolar disorder. Advantages and limitations of the various analytical methods will be reviewed and discussed, together with an evaluation of the role of TDM. © 2009 Bentham Science Publishers Ltd

Prediction of chromatographic retention time in high-resolution anti-doping screening data using artificial neural networks

The computational generation of gradient retention time data for retrospective detection of suspected sports doping species in postanalysis human urine sample data is presented herein. Retention data for a selection of 86 compounds included in the London 2012 Olympic and Paralympic Games drug testing schedule were used to train, verify, and test a range of computational models for this purpose. Spiked urine samples were analyzed using solid phase extraction followed by ultrahigh-pressure gradient liquid chromatography coupled to electrospray ionization high-resolution mass spectrometry. Most analyte retention times varied ≤0.2 min over the relatively short runtime of 10 min. Predicted retention times were within 0.5 min of experimental values for 12 out of 15 blind test compounds (largest error: 0.97 min). Minimizing the variance in predictive ability across replicate networks of identical architecture is presented for the first time along with a quantitative discussion of the contribution of each selected molecular descriptor toward the overall predicted value. The performance of neural computing predictions for isobaric compound retention time is also discussed. This work presents the application of neural networks to the prediction of gradient retention time in archived high-resolution urine analysis sample data for the first time in the field of anti-doping

Innovative analytical methods for Central Nervous System Drug analysis in biological fluids

During recent years a consistent number of central nervous system (CNS) drugs have been approved and introduced on the market for the treatment of many psychiatric and neurological disorders, including psychosis, depression, Parkinson disease and epilepsy. Despite the great advancements obtained in the treatment of CNS diseases/disorders, partial response to therapy or treatment failure are frequent, at least in part due to poor compliance, but also genetic variability in the metabolism of psychotropic agents or polypharmacy, which may lead to sub-therapeutic or toxic plasma levels of the drugs, and finally inefficacy of the treatment or adverse/toxic effects. With the aim of improving the treatment, reducing toxic/side effects and patient hospitalisation, Therapeutic Drug Monitoring (TDM) is certainly useful, allowing for a personalisation of the therapy. Reliable analytical methods are required to determine the plasma levels of psychotropic drugs, which are often present at low concentrations (tens or hundreds of nanograms per millilitre). The present PhD Thesis has focused on the development of analytical methods for the determination of CNS drugs in biological fluids, including antidepressants (sertraline and duloxetine), antipsychotics (aripiprazole), antiepileptics (vigabatrin and topiramate) and antiparkinsons (pramipexole). Innovative methods based on liquid chromatography or capillary electrophoresis coupled to diode-array or laser-induced fluorescence detectors have been developed, together with the suitable sample pre-treatment for interference removal and fluorescent labelling in case of LIF detection. All methods have been validated according to official guidelines and applied to the analysis of real samples obtained from patients, resulting suitable for the TDM of psychotropic drugs

Use of ultra-high pressure liquid chromatography coupled to high resolution mass spectrometry for fast screening in high throughput doping control

We describe a sensitive, comprehensive and fast screening method based on liquid chromatography-high resolution mass spectrometry for the detection of a large number of analytes in sports samples. UHPLC coupled to high resolution mass spectrometry with polarity switching capability is applied for the rapid screening of a large number of analytes in human urine samples. Full scan data are acquired alternating both positive and negative ionisation. Collision-induced dissociation with positive ionisation is also performed to produce fragment ions to improve selectivity for some analytes. Data are reviewed as extracted ion chromatograms based on narrow mass/charge windows (+/- 5 ppm). A simple sample preparation method was developed, using direct enzymatic hydrolysis of glucuronide conjugates, followed by solid phase extraction with mixed mode ion-exchange cartridges. Within a 10 min run time (including re-equilibration) the method presented allows for the analysis of a large number of analytes from most of the classes in the World Anti-Doping Agency (WADA) Prohibited List, including anabolic agents, beta 2-agonists, hormone antagonists and modulators, diuretics, stimulants, narcotics, glucocorticoids and beta-blockers, and does so while meeting the WADA sensitivity requirements. The high throughput of the method and the fast sample pre-treatment reduces analysis cost and increases productivity. The method presented has been used for the analysis of over 5000 samples in about one month and proved to be reliable. (C) 2013 Elsevier B.V. All rights reserved.</p

A simple high pH liquid chromatography-tandem mass spectrometry method for basic compounds: Application to ephedrines in doping control analysis

Solvent systems for use with LC-MS often result in a compromise between chromatographic performance and mass spectrometric detection, exemplified here by a LC-MS/MS method development for the analysis of ephedrines in doping control. Ephedrines, frequently found in therapeutic and nutritional preparations, are among the most commonly administered doping agents in competitive sport. Improved separation of these hydrophilic, basic compounds, some of which are diastereoisomers, is achieved in reversed-phase LC by the use of a high pH mobile phase in order to suppress analyte ionisation, and thus alter their polarity, resulting in reduced peak tailing and enhanced retention. However, when coupled to an ESI-MS detector, this eluent composition generated a non-linear and poorly reproducible signal. APCI yielded greater stability and reproducibility and is here presented as an ion source for the analysis of basic compounds under conditions that suppress their ionisation. Errors as large as 49.3% were observed with ESI, compared with 15.4% generated using APCI, for pseudoephedrine over the calibration range (25-400 mu g/mL) in urine with a simple dilution and injection of samples. These data highlight the importance of suitable MS conditions for stable performance, necessary for accurate quantification, without undue compromise to the LC separation. (C) 2010 Elsevier B.V. All rights reserved

Determination of plasma and urine levels of Δ9-tetrahydrocannabinol and its main metabolite by liquid chromatography after solid-phase extraction

Δ9-tetrahydrocannabinol is the most widespread drug of abuse in the world and it is also currently available as the active principle of formulations for the treatment of chronic pain. Its main metabolite, 11-nor-∆9-tetrahydrocannabinol-9-carboxylic acid, is the most important marker of Δ9-tetrahydrocannabinol consumption. An original liquid chromatographic method has been developed for the determination of these two analytes in human plasma and urine. Separation was obtained on a C8 column using a mobile phase with 35% phosphate buffer at pH 2.7 and 65% acetonitrile. The UV detector was set at 220 nm and indomethacin was used as the internal standard. Sample pre-treatment was carried out by solid-phase extraction with C8 cartridges; urine samples were subjected to basic hydrolysis before extraction. Both extraction yields (> 91%) and precision values were highly satisfactory. The method was successfully applied to biological samples collected from Cannabis users. Accuracy and selectivity results were satisfactory. This is the first HPLC-UV method developed for the simultaneous quantification of Δ9-tetrahydrocannabinol and 11-nor-∆9-tetrahydrocannabinol-9-carboxylic acid in both plasma and urine for the monitoring of either therapeutic or recreational use

Sensitive and selective glutathione determination in probiotic bacteria by capillary electrophoresis - laser induced fluorescence

Glutathione (GSH) is a thiol playing an important role in tissue protection against oxidative stress, which has been also related to carcinogenesis in the colon; from this point of view, the development of probiotic species producing glutathione could be of great interest. In order to determine the glutathione content of some probiotic bacteria of the Bifidobacterium and Lactococcus genera, a very sensitive and selective analytical method based on capillary electrophoresis coupled to laser induced fluorescence detection was developed. The pre-treatment of cell lysate samples is very simple and feasible: protein precipitation was carried out with acetonitrile in a 1:2 volume ratio. The fluorophore 5-iodoacetamidofluorescein (5-IAF) was chosen for glutathione derivatisation; it reacts with thiols at pH 12.5, forming a fluorescent adduct which is excited by laser at 488 nm for detection. The reaction parameters were optimised in terms of temperature, time and 5-IAF/GSH molar ratio. The electrophoretic analysis was carried out using a background electrolyte composed of carbonate buffer (25 mM, pH 9.8) and applying a 30 kV voltage; a complete electrophoretic run lasts less than 7 minutes. Good linearity was found in the 2.5-500.0 ng/mL concentration range of GSH; LOD = 0.5 ng/mL. The glutathione content in probiotic cells was determined using the standard additions method in order to reduce matrix effect. The method has been fully validated and has resulted to be suitable in terms of sensitivity and selectivity for the determination of GSH in probiotic cell lysates