Gelatin microsphere coated Fe3O4@graphene quantum dots nanoparticles as a novel magnetic sorbent for ultrasound-assisted dispersive magnetic solid-phase extraction of tricyclic antidepressants in biological samples.

Gelatin microsphere-coated Fe3O4@graphene quantum dots (Fe3O4@GQD@GM) were designed and synthesized as a novel sorbent via ultrasonic-assisted dispersive magnetic solid-phase extraction (UA-DMSPE) method. The synthesized sorbent was identified and confirmed by FT-IR, XRD, VSM, and SEM techniques. UA-DMSPE was combined with corona discharge ion mobility spectrometry for trace determination of desipramine, sertraline, and citalopram. Effective parameters were considered and optimized. The proposed method, under optimal conditions, showed excellent linearity in different concentration ranges (2-700 ng mL-1, R2 > 0.995), repeatability (RSD < 5.1%), good sensitivity (LODs in the range 0.6-1.5 ng mL-1), high preconcentration factor (PF = 207-218), and acceptable relative recoveries (93.5-101.8%). Eventually, this method was used to determine tricyclic antidepressants in various biological samples. Schematic presentation of the microextraction and monitoring of TCAs by ultrasonic-assisted dispersive magnetic solid phase microextraction-ion mobility spectrometry producer.

Super paramagnetic core-shells anchored onto silica grafted with C8/NH2 nano-particles for ultrasound-assisted magnetic solid phase extraction of imipramine and desipramine from plasma.

In current work the Fe3O4 magnetic nano-particles anchored to core-shells of SiO2 which grafted by C8/NH2 dual mixed groups, have been synthesized. The magnetic nano-particles were characterized by scanning electron microscopy, X-ray diffraction spectroscopy, and zeta-potential reader. The resulted nano-particles have spherical structure with diameters in the range of 105 to 110 nm. A magnetic solid phase extraction method was developed for extraction of imipramine and desipramine from human plasma samples under ultrasonic conditions by using of prepared NPs as sorbent. The MNPs were dispersion in plasma under sonicated conditions, accumulated by an external magnetic field and washed with Briton-Robinson buffer-acetonitrile solution (0.05 mol l-1, pH = 5, 10%V/V). The drugs were removed by methanol and quantified by gas chromatography. The calibration curves (correlation coefficient > 0.99) for IMP and DES were linear in the concentration range of 0.005 to 5 and 0.01 to 4 µg ml-1, respectively. The LOD, LOQ, intra and inter-day precision values were measured too. The proposed Fe3O4/SiO2/C8/NH2 MNPs could be applied for 3.0 times.

Determination of desipramine in biological samples using liquid-liquid-liquid microextraction combined with in-syringe derivatization, gas chromatography, and nitrogen/phosphorus detection.

A method was established for the determination of desipramine in biological samples using liquid-liquid-liquid microextraction followed by in-syringe derivatization and gas chromatography-nitrogen phosphorus detection. The extraction method was based on the use of two immiscible organic solvents. n-Dodecane was impregnated in the pores of the hollow fiber and methanol was placed inside the lumen of the fiber as the acceptor phase. Acetic anhydride was used as the reagent for the derivatization of the analyte inside the syringe barrel. Parameters that affect the extraction efficiency (composition of donor and acceptor phase, ionic strength, sample temperature, and extraction time) as well as derivatization efficiency (amount of acetic anhydride and reaction time and temperature) were investigated. The limit of detection was 0.02 µg/L with intra and interday RSDs of 2.6 and 7.7%, respectively. The linearity of the method was in the range of 0.2-20 µg/L (r(2) = 0.9986). The method was successfully applied to determine desipramine in human plasma and urine.

Electrospray ionization-ion mobility spectrometry as a detection system for three-phase hollow fiber microextraction technique and simultaneous determination of trimipramine and desipramine in urine and plasma samples.

A novel method based on three-phase hollow fiber microextraction technique (HF-LPME) coupled with electrospray ionization-ion mobility spectrometry (ESI-IMS) was developed for the simultaneous determination of two antidepressant drugs (trimipramine and desipramine) in urine and plasma samples. The effects of various parameters such as type of organic solvent, composition of donor and acceptor phase, stirring rate, salt addition, extraction time, and temperature were investigated. Under the optimized conditions, the relative standard deviation was in the range of 5-6%, and the method quantitation limit (MQL) of utilizing HF-LPME/ESI-IMS was 5 µg/L for both drugs. The relative recoveries obtained by the proposed method from urine and plasma samples were in the range 94% to 97% for trimipramine and 92% to 96% for desipramine. Finally, the feasibility of the proposed method was successfully confirmed by extraction and determination of trace amounts of trimipramine and desipramine in biological samples without any significant matrix effect.

The analysis of basic and acidic compounds using non-aqueous CE and non-aqueous CE-MS.

It has been shown that non-aqueous capillary electrophoresis (NACE) can provide improved separations in comparison to those obtained using conventional CE under aqueous conditions (ACE). Previous work carried out in our laboratories involving initial investigations into the technique have been reported. Based on the findings of that work it was possible to separate a variety of basic pharmaceuticals from selected impurities and to obtain the successful separation of some hydrophobic sulphonic acids. The successful coupling of NACE to mass spectrometry (NACE-MS) has also been demonstrated.

Simultaneous quantification of fluoxetine, norfluoxetine, and desipramine using gas chromatography with nitrogen-phosphorus detection.

The combination of fluoxetine (FLU) and desipramine (DMI) has been reported to be useful for the treatment of depression, and these drugs are also known to undergo a metabolic drug-drug interaction because of their effects on cytochrome P-450 2D6. A procedure that separates these two drugs and norfluoxetine (NFLU), the N-demethylated metabolite of FLU, and that allows simultaneous quantification of their levels would be of value and has been developed in our laboratories. The procedure involves an initial extraction into ethyl acetate after basification of the homogenate. The organic phase is retained and taken to dryness; the residue is reconstituted in water and acetylated with acetic anhydride under slightly basic conditions. Ethyl acetate is then used to extract the acetylated compounds from the aqueous medium. The organic layer is taken to dryness and the residue reconstituted in toluene. An aliquot of the solution in toluene is injected directly into a gas chromatograph equipped with a nitrogen-phosphorus detector, a fused silica capillary column, and an integrator/printer. Maprotiline is added to the initial homogenate and carried through the procedure as the internal standard. The assay is rapid and sensitive and has been applied successfully to liver and brain tissue taken from rats treated with FLU, DMI, or the combination.

Determination of serum desipramine and 2-hydroxydesipramine for pharmacokinetic applications by HPLC with ultraviolet detection.

This procedure for measuring desipramine and its 2-hydroxy metabolite in serum at a minimum concentration of 1 micrograms/L involves high-performance liquid chromatography (HPLC), with ultraviolet detection at 214 nm. After desipramine and 2-hydroxydesipramine are extracted from alkalinized serum by a single-step solvent extraction, they are separated by HPLC and quantified with amitriptyline as the internal standard. Desipramine, 2-hydroxydesipramine, and amitriptyline are separated in 6 min. The standard curve is linear (r = 1.000) for both desipramine and 2-hydroxydesipramine concentrations over the range of 1 to 100 micrograms/L, and the assay demonstrates an excellent precision profile, even at low concentrations. Between-run CVs for 20 and 60 micrograms/L controls (n = 20) were 3.9% and 3.6% for desipramine and 3.4% and 3.8% for 2-hydroxydesipramine, respectively. In a pharmacokinetic evaluation of patients with depression, we examined single-dose elimination curves before and after a four-week regimen of desipramine treatment. The results showed that the method's simplicity and high precision render it ideal for pharmacokinetic studies of desipramine.