Flow-injection on-line oxidizing fluorimetry and solid phase extraction for determination of thioridazine hydrochloride in human plasma

Equipment of Vertically-Ordered Mesoporous Silica Film on Electrochemically Pretreated Three-Dimensional Graphene Electrodes for Sensitive Detection of Methidazine in Urine

Direct, rapid, and sensitive detection of drugs in complex biological samples is essential for drug abuse control and health risk assessment. In this work, an electrochemical sensor was fabricated based on equipment of vertically-ordered mesoporous silica film (VMSF) on an electrochemically pre-treated three-dimensional graphene electrode (p-3DG), which can achieve direct and sensitive determination of methylthiopyridazine (TR) in urine. Three-dimensional graphene (3DG) with a continuous and interpenetrating graphene network was used as the supporting electrode and simple electrochemical polarization was employed to pre-treat 3DG to improve surface hydrophilicity and electrocatalytic performance. VMSF was easily grown using an electrochemical assisted self-assembly method within 10 s and was stably bound to the p-3DG surface. The nanochannel array on the as-prepared VMSF/p-3DG sensor enriched positively charged TR, leading to significantly improved electrochemical signal. Combined with the high electric activity of p-3DG and the enrichment of nanochannels, VMSF/p-3DG realized sensitive determination of TR ranging from 50 nM to 10 μM with a low detection limit (DL, 30 nM). Owing to the anti-fouling and anti-interference performance of VMSF, the common electroactive molecules including ascorbic acid (AA) and uric acid (UA) did not interfere with the detection. In addition, the detection of TR in buffer and urine exhibited similar sensitivity. Accurate detection of TR in urine was realized.

Occurrence, detection and ecotoxicity studies of selected pharmaceuticals in aqueous ecosystems- a systematic appraisal

Pharmaceutical compounds (PCs) have globally emerged as a significant group of environmental contaminants due to the constant detection of their residues in the environment. The main scope of this review is to fill the void of information on the knowledge on the African occurrence of selected PCs in environmental matrices in comparison with those outside Africa and their respective toxic actions on both aquatic and non-aquatic biota through ecotoxicity bioassays. To achieve this objective, the study focused on commonly used and detected pharmaceutical drugs (residues). Based on the conducted literature survey, Africa has the highest levels of ciprofloxacin, sulfamethoxazole, lamivudine, acetaminophen, and diclofenac while Europe has the lowest of all these PC residues in her physical environments. For ecotoxicity bioassays, the few data available are mostly on individual groups of pharmaceuticals whereas there is sparsely available data on their combined forms.

Sensitive determination of psychotropic drugs in urine samples using continuous liquid-phase microextraction with an extraction solvent lighter than water

A novel extraction vessel was employed, for the first time, in continuous liquid-phase microextraction (CLPME) with an extraction solvent lighter than water for the extraction of psychotropic drugs from urine samples.

Rapid determination of some psychotropic drugs in complex matrices by tandem dispersive liquid-liquid microextraction followed by high performance liquid chromatography

Simple and rapid determinations of some psychotropic drugs in some pharmaceutical wastewater and human plasma samples were successfully accomplished via the tandem dispersive liquid-liquid microextraction combined with high performance liquid chromatography-ultraviolet detection (TDLLME-HPLC-UV). TDLLME of the three psychotropic drugs clozapine, chlorpromazine, and thioridazine was easily performed through two consecutive dispersive liquid-liquid microextractions. By performing this convenient method, proper sample preconcentrations and clean-ups were achieved in just about 7min. In order to achieve the best extraction efficiency, the effective parameters involved were optimized. The optimal experimental conditions consisted of 100μL of CCl₄ (as the extraction organic solvent), and the pH values of 13 and 2 for the donor and acceptor phases, respectively. Under these optimum experimental conditions, the proposed TDLLME-HPLC-UV technique provided a good linearity in the range of 5-3000ngmL^-1 for the three psychotropic drugs with the correlation of determinations (R²s) higher than 0.996. The limits of quantification (LOQs) and limits of detection (LODs) obtained were 5.0ngmL^-1 and 1.0-1.5ngmL^-1, respectively. Also the proper enrichment factors (EFs) of 96, 99, and 88 for clozapine, chlorpromazine, and thioridazine, respectively, and good extraction repeatabilities (relative standard deviations below 9.3%, n=5) were obtained.

Green synthesis of nitrogen-doped carbon dots from lentil and its application for colorimetric determination of thioridazine hydrochloride

A simple and green hydrothermal method is introduced for synthesis of nitrogen-doped carbon dots (N-CDs) by using lentil. The interaction of as-prepared N-CDs with AgNPs was utilized for colorimetric detection of thioridazine hydrochloride.

Simultaneous determination of three banned psychiatric drugs in pig feed and tissue using solid-phase reactor on-line oxidizing and HPLC-fluorescence detection

The banned addition of psychiatric drugs such as phenothiazines to animal feed and foodstuffs increases the risk of human organ lesion. Phenothiazines usually exhibit weak native fluorescence and can be oxidized to strongly fluorescent compounds. In this study, a novel, sensitive and convenient method of HPLC-fluorescence detection based on post-column on-line oxidizing with lead dioxide solid-phase reactor has been developed for simultaneous determination of three banned psychotropic drugs, promethazine, chlorpromazine and thioridazine. Three compounds were successfully separated on an Agilent TC-C18 column with mobile phase of acetonitrile (A) and water (B), both containing 0.5% (v/v) formic acid. A gradient elution was programmed and fluorimetric detection was performed at λex /λem of 332/373 nm for promethazine, 340/380 nm for chlorpromazine and 352/432 nm for thioridazine. The calibration graphs gave good linearity over the concentration ranges of 30.0-4976.4 µg/L for promethazine, 2.0-2153.2 µg/L for chlorpromazine, and 15.0-3088.0 µg/L for thioridazine, and correlation coefficients (r) were ≥0.995. The method was applied to the determination of phenothiazines in pig feed and pig tissue, and the average spiked recoveries were in the range 69.1-115.4%.

High performance liquid chromatographic determination of ultra traces of two tricyclic antidepressant drugs imipramine and trimipramine in urine samples after their dispersive liquid-liquid microextraction coupled with response surface optimization

Dispersive liquid-liquid microextraction (DLLME) coupled with high performance liquid chromatography by ultraviolet detection (HPLC-UV) as a fast and inexpensive technique was applied to the determination of imipramine and trimipramine in urine samples. Response surface methodology (RSM) was used for multivariate optimization of the effects of seven different parameters influencing the extraction efficiency of the proposed method. Under optimized experimental conditions, the enrichment factors and extraction recoveries were between 161.7-186.7 and 97-112%, respectively. The linear range and limit of detection for both analytes found to be 5-100ng mL(-1) and 0.6ng mL(-1), respectively. The relative standard deviations for 5ng mL(-1) of the drugs in urine samples were in the range of 5.1-6.1 (n=5). The developed method was successfully applied to real urine sample analyses.