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Lipids play important roles at various stages of host–pathogen interactions, determine pathogens virulence, modulate plant defenses and might also function as modulators of several pathways in cell-to-cell communication. Free Fatty Acids (FFA) oxidated by enzymes [e.g., lipoxygenases (LOXs) and dioxygenases (DOXs)] form oxylipins, that have been extensively studied in plant–pathogen interaction. The oxylipins show a structural similarity among plant, fungal and bacterial prompting the hypothesis that they are important in cross-kingdom communication. We presented here the results within European XF-ACTORS and Italian SALAVOLIVI and OLIDIXIIT projects. The studies were carried out with Xylella fastidiosa subsp. pauca (Xfp) grown in vitro amending or not different lipids entities to characterize the bacterial lipidome. The results support the hypothesis that FFA and oxylipins change in the different Xfp lifestyle and are crucial to modulate the pathogen lifestyle. Further we analysed the lipidome of Nicotiana tabacum and Olea europaea, artificially and naturally infected (Olive Quick Decline Syndrome - OQDS) with Xfp, respectively. LC-TOF and LC-MS/MS analysis pinpointed that the FFA and the oxylipins derived by the oleic, linoleic and linolenic acid are differently accumulated in infected plants versus non infected and some lipid entities are hallmarking of infection. Basing on the knowledge of oxylipins as cellular signals in different pathosystems, we can assume that lipids can act as signals for reshaping the lifestyle of the contenders and sometimes determining the fate of the challenge. These studies demonstrate, for the first time in a phytopathogenic bacteria, that the LOX- and DOX-oxylipins can influence the bacterial “status” and are differently accumulated in infected versus non infected plants. More efforts should be conducted to unveil if this lipid entities pave the way to Xylella pathogenicity or simply facilitate it. These hallmarks can be employed as markers of OQDS and/or for developing new control strategies.

The aim of this study was to examine the relationship between visual field (VF) loss, vision-related quality of life (QoL) and glaucoma-related symptoms in a large cohort of primary open angle glaucoma (POAG) patients. POAG patients with or without VF defects or “glaucoma suspect” patients were considered eligible. QoL was assessed using the validated versions of the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and glaucoma-related symptoms were assessed using the Glaucoma Symptom Scale (GSS). Patients were classified as having VF damage in one eye (VFD-1), both eyes (VFD-2), or neither eye (VFD-0). 3227 patients were enrolled and 2940 were eligible for the analysis. 13.4% of patients were classified in the VFD-0, 23.7% in the VFD-1, and 62.9% in the VFD-2 group. GSS visual symptoms domain (Func-4) and GSS non-visual symptoms domain (Symp-6) scores were similar for the VFD-0 and VFD-1 groups (p = 0.133 and p = 0.834 for Func-4 and Symp-6, respectively). VFD-0 group had higher scores than VFD-2 both in Func-4 (p

Classical (haloperidol and chlorpromazine) and atypical neuroleptics (olanzapine, clozapine, loxapine, and risperidone) were quantified in pharmaceutical formulations (tablets, capsules, and oral solutions) by capillary zone electrophoresis. The simple sample pretreatment consists of a one-step extraction, filtration, and dilution. The electrophoretic conditions were as follows: uncoated fused-silica capillary (28.3 cm total length, 22.0 cm effective length, 50 μm I.D.), phosphate buffer (pH 2.5, ionic strength 35 mmol/L). The separation voltage (15 kV) results in a current lower than 50 μA. UV detection was performed at 214 nm. Calibration curves were linear in the 5–50 μg/mL range for all tested drugs (r better than 0.999). The repeatability (or intra-day precision), expressed by the relative standard deviation, was better than 2% (6 measurements). The accuracy, resulting from recovery studies, was between 98 and 105 %. The amount of drug found agreed with the declared contents within the limits specifi...

Several strategies to improve the separation of 11 central nervous system drugs (antipsychotics and antidepressants) with capillary zone electrophoresis were applied: the variation of the pH of the buffering background electrolyte, its ionic strength, addition of inclusion-complex forming beta-cyclodextrin or polyvinylpyrrolidone (PVP), respectively, as a replaceable, soluble, polymeric pseudo-stationary phase. Best separation was achieved at pH 2.5 and 35 mmol/l ionic strength (phosphate buffer), with 0.5% (w/v) PVP.

The concentrations of vitamin A, beta-carotene, and all-trans-retinoic acid in oral preparations were determined in a single analysis by a method based on isocratic, reversed-phase liquid chromatography (LC). The LC system consisted of a C18 column, a mobile phase of acetonitrile, dichloromethane, methanol, and water and a UV detector set at 330 nm. The linearity ranges were 25-250 ng/mL for trans-retinoic acid and vitamin A, and 100-1,000 ng/mL for beta-carotene. This LC method for the determination of retinoids is simple, precise, and accurate. No extraction procedure is required before the chromatographic analysis; only a suitable dilution is necessary. The method proved to be reliable, fast, and economical. Furthermore, this method is indicative of stability, because it allows for the determination of degradation products such as 13-cis-retinoic acid.

Three different analytical methods for the quality control of clozapine in commercial formulations were developed and compared: a liquid chromatographic (LC) method with UV detection, a capillary zone electrophoretic (CZE) method, and a linear scan voltammetric (LSV) method. The isocratic LC procedure used a C18 reversed-phase column; the CZE method used an uncoated fused-silica capillary and phosphate buffer containing polyvinylpyrrolidone as the background electrolyte; the LSV method analyzed clozapine solutions with acidic phosphate buffer as the supporting electrolyte. The 3 methods gave similar and satisfactory results, in terms of precision and accuracy. Repeatability and intermediate precision were good (RSD%2.2) and accuracy, resulting from recovery studies, was between 98 and 102%. The rapidity of analysis was high for all 3 methods, especially for the LSV.

Two antipsychotic drugs (clozapine and loxapine) and six metabolites, N-demethylclozapine, clozapine N-oxide, N-demethylloxapine (amoxapine), 7-hydroxyloxapine, 8-hydroxyloxapine, 8-hydroxyamoxapine, were separated by capillary zone electrophoresis. Variation of pH and ionic strength of the acidic phosphate buffer (pH below 4) did not enable the separation of loxapine and one of its metabolites. Resolution of the single parent drugs and their metabolites was possible in background electrolytes (phosphate, pH 3.5, 60 mmol/l) containing either 0.2% (w/v) polyvinylpyrrolidone as replaceable pseudo-stationary phase, or 0.75 mmol/l beta-cyclodextrin added as complex-forming agent. Full separation of the mixture with baseline resolution of all analytes was obtained with a background electrolyte with heptakis-6-sulfato-beta-cyclodextrin added as negatively charged complexation agent with improved separation selectivity.

The CO2 Laser is used in the treatment of several laryngeal diseases and offers considerable advantages over traditional techniques. New applications of this surgical tool are currently under study for other laryngeal and ENT pathologies. It should be pointed out that there are some limitations to the use of the CO2 Laser; an accurate examination of its indications is needed, as well as a precise knowledge of its techniques and possibilities.

To evaluate the change over time of vision-related quality of life (QoL) and glaucoma symptoms in a population of newly-diagnosed primary open angle glaucoma (POAG) patients. Multicenter, prospective study. Consecutive newly-diagnosed POAG patients were enrolled and followed-up for one year. Follow-up visits were scheduled at 6 and 12 months from baseline. At each visit, vision-related QoL and glaucoma-related symptoms were assessed by the means of the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and the Glaucoma Symptom Scale (GSS), respectively. Trends over time for NEI-VFQ-25 and GSS scores were evaluated with longitudinal linear mixed models. One-hundred seventy-eight patients were included in the analysis. At baseline, early to moderate glaucoma stages were associated with higher scores for most GSS and NEI-VFQ-25 items, while lower best-corrected visual acuity was associated with lower scores for 4 of the 12 NEI-VFQ-25 items. During the follow-up, all the GSS scores, the NEI-VFQ-25 total score, and 7 of the 12 NEI-VFQ-25 scores significantly improved (p

Purpose: The purpose of this article was to evaluate the potential association between sociodemographic factors with clinical characteristics, vision-related quality of life (QoL), and glaucoma-related symptoms scores in a large cohort of primary open-angle glaucoma patients. Materials and Methods: Multicenter, cross-sectional study involving academic and nonacademic centers. Previously diagnosed primary open-angle glaucoma patients aged >18 years were enrolled. At baseline, information on demographic characteristics, social, medical and ocular history, clinical presentation and treatments was collected. Vision-related QoL was evaluated by means of the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25), while glaucoma-related symptoms were evaluated using the Glaucoma Symptom Scale (GSS) questionnaire. The associations between sociodemographic factors with clinical characteristics (mean deviation, pattern standard deviation, best-corrected visual acuity), NEI-VFQ-25, and GSS scores were evaluated by means of univariate and multivariate general linear models. Results: A total of 3227 patients were enrolled. Older age and male sex were significantly associated with lower mean deviation (P

Chronic obstructive pulmonary disease (COPD) increases the risk of mortality in non-valvular atrial fibrillation (NVAF) patients. Data on the relationship of COPD to major cardiovascular events (MACE) in AF have not been defined. The aim of the study is to assess the predictive value of COPD on incident MACE in NVAF patients over a 3-year follow-up. In the Atrial Fibrillation Registry for Ankle-Brachial Index Prevalence Assessment-Collaborative Italian Study (ARAPACIS) cohort, we evaluate the impact of COPD on the following clinical endpoints: MACE (including vascular death, fatal/non-fatal MI and stroke/TIA), cardiovascular (CV) death and all-cause mortality. Among 2027 NVAF patients, patients with COPD (9%) are more commonly male, elderly and at higher thromboembolic risk. During a median 36.0months follow-up, 186 patients experienced MACE: vascular death (n = 72), MI (n = 57), stroke/TIA (n = 57). All major outcomes (including stroke/TIA, MI, vascular death, and all-cause death) are centrally adjudicated. Kaplan–Meier curves show that NVAF patients with COPD are at higher risk for MACE (p < 0.001), CV death (p < 0.001) and all-cause death (p < 0.001). On Cox proportional hazard analysis, COPD is an independent predictor of MACE (Hazard ratio [HR] 1.77, 95% Confidence Intervals [CI] 1.20–2.61; p = 0.004), CV death (HR 2.73, 95% CI 1.76–4.23; p < 0.0001) and all-cause death (HR 2.16, 95% CI 1.48–3.16; p < 0.0001). COPD is an independent predictor of MACE, CV death and all-cause death during a long-term follow-up of NVAF patients.

A reliable micellar electrokinetic capillary chromatographic method was developed and validated for the determination of lamotrigine and its metabolites in human plasma and urine. The variation of different parameters, such as pH of the background electrolyte (BGE) and Sodium dodecyl sulfate (SDS) concentration, were evaluated in order to find optimal conditions. Best separation of the analytes was achieved using a BGE composed of 10 mM borate and 50 mM SDS, pH 9.5; melatonin was selected as the internal standard. Isolation of lamotrigine and its metabolites from plasma and urine was accomplished with an original solid-phase extraction procedure using hydrophilic-lypophilic balance cartridges. Good absolute recovery data and satisfactory precision values were obtained. The calibration plots for lamotrigine and its metabolites were linear over the 1-20 microg/mL concentration range. Sensitivity was satisfactory; the limits of detection and quantitation of lamotrigine were 500 ng/mL and 1 microg/mL, respectively. The application of the method to real plasma samples from epileptic patients under therapy with lamotrigine gave good results in terms of accuracy and selectivity, and in agreement with those obtained with an high-performance liquid chromatography (HPLC) method.

An overview of the electrokinetic chromatographic methods for the analysis of antiepileptic drug levels in biological samples is presented. In particular, micellar electrokinetic capillary chromatography is a very suitable method for the determination of these drugs, because it allows a rapid, selective, and accurate analysis. In addition to the electrokinetic chromatographic studies on the determination of antiepileptic drugs, some information regarding sample pretreatment will also be reported: this is a critical step when the analysis of biological fluids is concerned. The electrokinetic chromatographic methods for the determination of recent antiepileptic drugs (e.g., lamotrigine, levetiracetam) and classical anticonvulsants (e.g., carbamazepine, phenytoin, ethosuximide, valproic acid) will be discussed in depth, and their pharmacological profiles will be briefly described as well.

Stationary phases for capillary electrochromatography with a longitudinal gradient of functionalities have been prepared via photoinitiated grafting of polymer chains onto the pore surface of a porous polymer monolith. In order to achieve the desired retention and electroosmotic flow, the hydrophobic poly(butyl methacrylate-co-ethylene dimethacrylate) monolith with optimized porous properties was grafted with a layer of ionizable polymer, poly(2-acrylamido-2-methyl-1-propanesulfonic acid). A moving shutter and a neutral density filter were used to control the dose of UV light received at different locations along the monolith in order to create the longitudinal gradient of functionalities. Formation of the desired gradients was confirmed using electron probe microanalysis of different locations along the column. The preparation technique significantly affects performance in the CEC mode as demonstrated on the separations of a model mixture using columns both with homogeneous distribution of grafts and with a gradient of functionality. Columns grafted with the gradient of functionalities were found superior to those functionalized uniformly. A comparison of the performance of the gradient column with another containing evenly distributed functionalities showed the performance benefits of the "gradient" column.

The introduction in clinical practice of new antipsychotic drugs neurologically safer and with a broader spectrum of efficacy than "classical" neuroleptics has brought about significant improvement in the therapy of schizophrenic patients. These second-generation antipsychotics, usually called "atypical" antipsychotics, have several therapeutical features in common, such as their effectiveness against the negative symptoms of schizophrenia and the advantage of not causing severe extrapyramidal symptoms and hyperprolactinemia. The therapeutic drug monitoring of patients treated with atypical antipsychotics is, however, still advisable. In many cases it can avoid the onset of side and toxic effects due to high plasma levels of the drug caused by overdose or interactions with other drugs. Furthermore, monitoring can significantly improve the patient's compliance, thus leading to higher treatment efficacy. The pharmacological properties of the most widely used atypical antipsychotics (clozapine, olanzapine, risperidone and quetiapine) will be treated herein with particular attention paid to chemical-clinical correlations. The analytical methods suitable for the therapeutical drug monitoring of these drugs will also be discussed. Other recent atypical agents (ziprasidone, aripiprazole, iloperidone, sertindole and zotepine) will be described as well.

Polymeric micelles based on polyvinyl alcohol substituted with oleic acid were used as vehicles for progesterone and folic acid. The ability of this amphiphilic polymer to entrap lipophilic drugs and to generate stable micelles in aqueous neutral medium makes it a good candidate for drug delivery. The release of the loaded drugs in acidic environments represents another important property of these systems. Size of micelles, their stability, and their drug-loading capacity were evaluated, as well as the in vitro controlled-release profiles at pH 7.4 and 5.5.

The development of new “atypical” antipsychotic agents, which are safer than classical neuroleptics and also active against the negative symptoms and neurocognitive deficits caused by the illness, has produced a significant advancement in the treatment of schizophrenia. The atypical (or “second generation”) antipsychotics have several therapeutical properties in common, however they can significantly differ with regard to clinical potency and side effects. The main features regarding pharmacodynamics, pharmacokinetics and pharmacological interactions of the most important atypical antipsychotics, namely clozapine, olanzapine, quetiapine and risperidone, are treated herein. Several analytical methods available for the therapeutic drug monitoring of these drugs are also presented, as well as the novel formulations, which can notably improve the therapy of schizophrenia. Other very recent atypical agents, such as ziprasidone, aripiprazole, iloperidone, sertindole and zotepine will also be briefly described.

La sertralina, (1S,4S)-4-(3,4-diclorofenil)1,2,3,4-tetraidro-1-naftil(metil)ammina, è un derivato della naftalenammina con predominante attività farmacologica inibitoria del reuptake presinaptico della serotonina. La sertralina è indicata per il trattamento della depressione maggiore, attacchi di panico, disturbi ossessivo compulsivi e stress post traumatico. Questo farmaco è somministrato per os in dosi giornaliere comprese tra 50 e 200 mg e poiché viene assorbito lentamente, un'unica somministrazione giornaliera è terapeuticamente efficace. La sertralina subisce un intenso metabolismo di primo passaggio ad opera del CYP450, è bio-trasformata in desmetil-sertralina, un metabolita debolmente attivo che si accumula in alte concentrazioni nel plasma allo "steady state". I livelli plasmatici terapeutici della sertralina sono compresi tra 2.8 e 112 ng/mL, sebbene con pronunciata variabilità interindividuale. Il farmaco non è esente da effetti collaterali, come ad esempio perdita dell’appetito, nausea, insonnia, che sono dose-correlati. Nel presente lavoro viene descritto un rapido e preciso metodo HPLC per la determinazione di sertralina e desmetil-sertralina in plasma umano. La separazione della sertralina e della desmetil sertralina è stata ottenuta utilizzando come fase stazionaria una colonna a fase inversa C8 e come fase mobile una miscela di tetrametilammonio perclorato e acetonitrile (50/50, v/v). La rivelazione spettrofotometrica degli analiti è stata effettuata a 230 nm. Un selettiva ed efficiente purificazione dei campioni plasmatici dalla matrice biologica è stata sviluppata per mezzo di una procedura estrattiva in fase solida che consente di concentrare il campione migliorando la sensibilità del metodo. La procedura analitica sviluppata è stata applicata all'analisi di sertralina in plasma di pazienti depressi in terapia farmacologica con Zoloft® 50 mg. Il metodo proposto sembra promettente per il TDM (Therapeutic Drug Monitoring) della sertralina come strumento per una giusta personalizzazione della terapia e attenta valutazione della compliance del farmaco e delle interazioni farmacologiche in pazienti in terapia con sertralina.

The use of photografting for the functionalization of porous poly(butyl methacrylate-co-ethylene dimethacrylate) monolithic columns enabled the preparation of columns with a homogeneously grafted poly(2-acrylamido-2-methyl-1-propanesulfonic acid, AMPS) chains. Recently, novel monolithic columns with a longitudinal gradient of concentration of functional groups were prepared and characterized using electron probe microanalysis and the separation performance evaluated in CEC. We demonstrated that these monolithic columns afforded higher separation efficiency and peak capacity compared to their homogeneously grafted counterparts. Consequently, the application of monolithic columns with this new type of chemistry enabled rapid and efficient separations. In this study, we now demonstrate the applicability of the new type of monolithic columns in µ-HPLC. For example, the separation of proteins in ion-exchange mode was studied. Optimization of the chromatographic conditions such as the shape of the mobile phase gradient and the flow rate allowed a rapid separation of four proteins in a short period of time. We also found that the stationary phase involving the gradient of functionalities exhibited high selectivity. These separation methods can be useful in the proteomic research.

Mirtazapine is a recent noradrenergic and specific serotonergic antidepressant drug. A capillary electrophoretic method has been developed for the enantioseparation and analysis of mirtazapine and its main active metabolite, N-desmethylmirtazapine, in human plasma. For method optimisation several experimental parameters were investigated, such as type and concentration of the chiral selector, buffer pH and capillary temperature. Baseline enantioseparation of the analytes was achieved in 2.5 minutes in a fused silica capillary (50 μm I.D.; 48.5 cm total length; 8.5 cm effective length) using carboxymethyl-beta-cyclodextrin, dissolved in a background electrolyte consisting of 50 mM phosphate buffer at pH 2.5, as the chiral selector. UV detection was set at 205 nm. A careful pre-treatment of plasma samples was developed, using solid-phase extraction with hydrophilic-lipophilic balance cartridges (60 mg, 3 mL), eluting the sample with methanol, then concentrating it 37.5 times before injection. Extraction yield values are very satisfactory, being the average 89% for mirtazapine and 73% for N-desmethylmirtazapine. Application of the method to some human plasma samples has given satisfactory results.

An accurate and precise high-performance liquid chromatographic method using diode array detection for the determination of the novel antiepileptic, Levetiracetam, has been developed. Three clean-up procedures for the analysis of Levetiracetam in human plasma were implemented and evaluated, namely solid-phase extraction, deproteinization by addition of organic solvents and formation of insoluble salts. Adenosine was used as the internal standard for all three sample pretreatment procedures. Among the several cartridges used for solid-phase extraction, the hydrophilic–lypophilic balance (Oasis® HLB) phase provides the best extraction yield of Levetiracetam, together with high precision. With the two other clean-up procedures involving plasma deproteinization by addition of methanol or zinc sulphate, lower sensitivity and precision of the assays were obtained. However, they are cheaper and faster when compared with the solid-phase extraction procedure. Copyright © 2003 John Wiley & Sons, Ltd.

Negli ultimi anni il trattamento farmacologico dei disturbi psichiatrici ha compiuto grandi progressi, soprattutto grazie all'introduzione in terapia dei nuovi farmaci antipsicotici ed antidepressivi. Da tempo il nostro gruppo di ricerca di Analisi Farmaco-Tossicologica, in collaborazione con Cliniche Psichiatriche e Servizi Psichiatrici, si è interessato allo sviluppo di metodi analitici idonei per il dosaggio dei livelli plasmatici di questi farmaci e dei loro metaboliti. In particolare, si sono studiati farmaci psicotropi appartenenti alle classi degli antipsicotici atipici (clozapina, olanzapina, risperidone, quetiapina), dei recenti antidepressivi SSRI (fluoxetina, citalopram), NaRI (reboxetina) e NaSSA (mirtazapina) e degli antiepilettici usati in psichiatria come stabilizzatori del tono dell'umore (acido valproico, carbamazepina, oxcarbazepina, lamotrigina, levetiracetam, fenitoina, primidone e fenobarbitale). Nell'ultimo decennio il monitoraggio terapeutico (TDM) di farmaci psicotropi ha acquistato sempre maggiore importanza; infatti, un’accurata determinazione dei livelli plasmatici in pazienti trattati con farmaci del Sistema Nervoso Centrale permette di ottenere importanti correlazioni chimico cliniche: dose - risposta, dose - livelli plasmatici, livelli plasmatici - effetti terapeutici, livelli plasmatici - effetti collaterali. Inoltre, spesso ai pazienti psicotici sono somministrati altri farmaci, come coadiuvanti della terapia o per patologie concomitanti, e la polifarmacoterapia che così si viene ad attuare può avere importanti effetti sulle caratteristiche di biodisponibilità e di efficacia dei singoli farmaci. Le informazioni ottenute mediante il TDM permettono anche in questi casi di ottenere un’ottimizzazione della terapia individuale, una riduzione degli effetti tossici e collaterali, una minimizzazione dei rapporti rischio/beneficio e una diminuzione dei casi e della durata delle ospedalizzazioni con conseguente riduzione dei costi. Affinchè i risultati del TDM siano pienamente affidabili, quindi di utilità per la personalizzazione della terapia, occorre considerare numerosi aspetti che vanno dal prelievo dei campioni ematici, alle modalità di conservazione e trasporto fino all'applicazione della tecnica analitica più idonea ed alla corretta valutazione dei dati ottenuti. Saranno qui presentati alcuni risultati derivanti dall'incontro tra le competenze cliniche dei Centri Psichiatrici e l'esperienza del nostro gruppo di ricerca nel campo dell’analisi farmaco-tossicologica. In particolare, saranno riportati i risultati dell'applicazione del TDM a pazienti in terapia con i recenti farmaci antipsicotici clozapina e olanzapina e l'antidepressivo fluoxetina. Si presenteranno casi di particolare interesse clinico quali intossicazioni, sovradosaggi e studi di interazione farmacologica, in cui il TDM ha permesso, costruendo un quadro chimico-clinico del paziente, di ottenere risultati utili applicando le opportune modifiche del regime terapeutico. Recentemente, il nostro gruppo di ricerca ha esteso il campo d'applicazione del TDM a numerosi altri farmaci utilizzati in Clinica Psichiatrica, quali gli antipsicotici classici aloperidolo, clorpromazina, zuclopentixolo, levomepromazina, loxapina e flufenazina, i nuovi antidepressivi sertralina e paroxetina e gli antidepressivi classici imipramina, clomipramina, dibenzepina, trazodone, maprotilina, protriptilina e amoxapina. In conclusione, una corretta applicazione del TDM è un mezzo efficace, rapido ed economico per migliorare la compliance del paziente e l'efficacia del trattamento farmacologico, risultando così un valido ausilio nella difficile procedura decisionale degli psichiatri. Sarebbe pertanto auspicabile che il TDM trovasse una sempre più ampia applicazione nel trattamento delle malattie psichiatriche.

The separation and simultaneous determination of caffeine, paracetamol, and acetylsalicylic acid in two analgesic tablet formulations was investigated by capillary electrochromatography (CEC). The effect of mobile phase composition on the separation and peak efficiency of the three analytes was studied and evaluated; in particular, the influence of buffer type, buffer pH, and acetonitrile content of the mobile phase was investigated. The analyses were carried out under optimized separation conditions, using a full-packed silica capillary (75 microm ID; 30.0 cm and 21.5 cm total and effective lengths, respectively) with a 5 microm C8 stationary phase. A mixture of 25 mM ammonium formate at pH 3.0 and acetonitrile (30:70 v/v) was used as the mobile phase. UV detection was at 210 nm. Good linearity was found in the range of 50-200, 20-160, and 4-20 microg/mL for acetylsalicylic acid (r2=0.9988), paracetamol (r2=0.9990) and caffeine (r2=0.9990), respectively. Intermediate precision (RSD interday) as low as 0.1-0.8% was found for retention times, while the RSD values for the peak area ratios (Aanalyte/AIS) were in the range of 1.9-2.9%. The optimized CEC method was applied to the analysis of the studied compounds present in commercial tablets.

Mirtazapine (1,2,3,4,10,14b-hexahydro-2-methyl-pyrazino[2,1-a]-pyrido[2,3-c][2-benzazepine]), is the first noradrenergic and specific serotonergic antidepressant ('NaSSA'), that was approved by the Food and Drug Administration for the treatment of depression in June 1997. It is administered clinically as Remeron®, a 50:50 mixture of S(+) and R(-) enantiomers, that is supplied for oral administration as scored film-coated tablets containing 15 or 30 mg of mirtazapine. It has two major metabolites, N-demethylmirtazapine and 8-hydroxymirtazapine. The parent compound demonstrates the major pharmacological activity. Some minor activity is shown by the demethyl metabolite while the hydroxy metabolite is not pharmacologically active. The receptor binding affinities of the enantiomers of mirtazapine are different, the (+) enantiomer being the more potent adrenoceptor antagonist of the two. For this reason a chiral separation of the enantiomers may be important in pharmacokinetic studies and for evaluating the clinical response. Aim of this study is the development of a capillary electrophoretic method for the enantioseparation of mirtazapine and its active metabolite. For method optimisation several parameters were investigated, such as cyclodextrin and buffer concentration, buffer pH and capillary temperature. Baseline enantioseparation of the racemic compounds was achieved in 2.5 minutes using a fused silica capillary (50 μm I.D. and 48.5, 40.0 cm, total and effective length, respectively), filled with a background electrolyte consisting of a 50 mM phosphate buffer at pH 2.5 supplemented with 0.3% (w/v) carboxymethyl-beta-cyclodextrin sulfate at 12.5°C and applying a voltage of 20 kV. UV detection was set at 205 nm. The implemented fast CZE stereoselective separation of mirtazapine has been applied for the determination of the enantiomeric purity of preparats containing racemic mirtazapine. The extraction of mirtazapine from the tablets consisted of a simple one-step dissolution with methanol, centrifugation and dilution. The electrophoretic procedure demonstrated to be very rapid and feasible and seems to be suitable for quality control of mirtazapine tablets. Experiments are in progress in order to apply the method to the determination of mirtazapine and its active metabolite in biological fluids.

The introduction of new antiepileptic drugs in the pharmacological treatment of different forms of epilepsy has led to a better quality of life for the great majority of patients. Moreover, the therapeutic drug monitoring is a well established procedure which helps to improve the effectivness of antiepileptic therapy, increasing clinical efficacy while minimizing adverse effects. Indeed, the plasma or urine concentrations of the parent drug and its main metabolites may provide an important link between drug dose and desirable and/or undesirable drug effects. For this reason, the development of a rapid and specific assays for lamotrigine and its key metabolites is critical to the study of metabolism and drug-drug interactions. The feasability of micellar electrokinetic chromatography in the analysis of antiepileptic drugs has been successfully proved by our research group for the determination of carbamazepine and oxcarbazepine. In the present work, a reliable micellar electrokinetic chromatographic method for the analysis of lamotrigine and its two main metabolites in human plasma and urine is described. The separation and determination of the analytes is achieved using a system consisting of 50 mM SDS in borate buffer (10 mM, pH 9.5). Separation is carried out in an uncoated fused-silica capillary with a separation voltage of 30 kV and currents typically less than 40 µA. Spectrophotometric detection is at 214 nm. Isolation of lamotrigine and its metabolites from plasma and urine is accomplished by a solid-phase extraction procedure using Oasis HLB cartridges. No interferences from the matrix are detected. The mean extraction yield of the analytes from biological samples is higher than 95%, thus very satisfactory Further assays are in progress in order to complete the method validation.