Simultaneous determination of citalopram and tadalafil by the second derivative synchronous fluorescence method in biological fluids; application of Box-Behnken optimization design

This is the first study focusing solely on that determination of tadalafil in the presence of citalopram as an antidepressant drug. The determination in biological fluids of a co-administered antidepressant drug and a sexual stimulation drug is a very critical and important step for psychotic and ischaemic heart disease patients, especially in cases of emergency and this requires therapeutic drug monitoring. A sensitive, efficient and rapid assay was selected satisfactorily and applied for simultaneous determination of citalopram and tadalafil either in their pure forms, in tablet dosage forms or in spiked human plasma. There was a large overlap for both drugs, forming the broad band found in conventional fluorescence spectra and their related synchronous fluorescence intensity. Therefore, the development of a highly sensitive second derivative synchronous fluorescence method was demonstrated that removed this overlap. The proposed method depended on measuring the amplitudes of the second derivative of synchronous fluorescence intensity at suitable wavelengths of 301 nm and 367 nm for citalopram and tadalafil at Δλ = 60 nm, respectively. Box-Behnken design as a response surface methodology was used to fit models and create an optimization process encompassing a set of factors and resulting in an optimum response value specifically designed for this method. Under optimum conditions, the linear dynamic ranges for citalopram and tadalafil estimation were 20-900 and 5-400 ng ml^-1 with detection limits of 5.40 and 1.43 ng ml^-1 , respectively.

Mirtazapine

Mirtazapine is one of antidepression which is used mainly in the treatment of depression, moreover, it is sometimes used in the treatment of anxiety disorders, insomnia, nausea, and vomiting, and to produce weight gain when desirable. The action of mirtazapine is an antagonist of certain adrenergic and serotonin receptors, and, furthermore, the drug is used strong as antihistamine, and it is occasionally defined as a noradrenergic and specific serotonergic antidepressant (NaSSA). The comprehensive profile of mirtazapine gives more detailed information about nomenclature, formulae, elemental analysis, and appearance. In addition, the numerous methods of drug synthesis are summarized. Also the profile covers the physicochemical properties as: the value of pK_a, drug solubility, melting point, X-ray powder diffraction, and analysis methods for example: (compendial, electrochemical, spectroscopic, and method of chromatographic). Besides that, the profile covered pharmacological profile and clinical pharmacokinetics in subtitle's (absorption, distribution, metabolism, and elimination). About 100 references were given as a proof of the above-mentioned studies.

Uptake of human pharmaceuticals in bull sharks (Carcharhinus leucas) inhabiting a wastewater-impacted river

The presence of human pharmaceuticals in sewage-impacted ecosystems is a growing concern that poses health risks to aquatic wildlife. Despite this, few studies have investigated the uptake of active pharmaceutical ingredients (APIs) in aquatic organisms. In this study, the uptake of 9 APIs from human drugs was examined and compared in neonate bull sharks (Carcharhinus leucas) residing in pristine (Myakka River) and wastewater-impacted (Caloosahatchee River) tributaries of Florida's Charlotte Harbor estuary. The synthetic estrogen used in human contraceptives (17α-ethynylestradiol) and 6 of the selective serotonin/norepinephrine reuptake inhibitors (citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, venlafaxine) used in human antidepressants were observed at detectable and, in some cases, quantifiable levels in plasma of Caloosahatchee River sharks. Comparatively, only venlafaxine was detected in the plasma of a single Myakka River shark at a level below the limit of quantitation. These results suggest that sharks residing in wastewater-impacted habitats accumulate APIs, a factor that may pose special risks to C. leucas since it is one of few shark species to regularly occupy freshwater systems. Further research is needed to determine if the low levels of API uptake observed in Caloosahatchee River bull sharks pose health risks to these animals.

Electroanalytical determination of paroxetine in pharmaceuticals

Electroanalytical methods based on square-wave adsorptive-stripping voltammetry (SWAdSV) and flow-injection analysis with SWAdSV detection (FIA-SWAdSV) were developed for the determination of paroxetine (PRX). The methods were based on the reduction of PRX at a mercury drop electrode at -1.55V versus Ag/AgCl, in a borate buffer of pH 8.8, and the possibility of accumulating the compound at the electrode surface. Because the presence of dissolved oxygen did not interfere significantly with the analysis, it was also possible to determine PRX using FIA-SWAdSV. This method enables analysis of up to 120 samples per hour at reduced costs. Both methods developed were validated and successfully applied to the quantification of PRX in pharmaceutical products.

Electroanalytical study of the antidepressant sertraline

A flow injection square wave cathodic stripping voltammetric method has been developed for the determination of sertraline in a pharmaceutical preparation. The method shows linearity between peak current intensity and sertraline concentration for the interval between 0.20 x 10(-6) and 1.20 x 10(-6) mol L(-1). Limits of detection and quantification were found to be 1.5 x 10(-7) and 5.0 x 10 (-7) mol L(-1), respectively. Up to 70 samples per hour can be analysed with a good precision (R.S.D. = 2.5%). The proposed method was successfully applied to the determination of sertraline in a commercial product. In the voltammetric determination of sertraline in flow, a high sample rate is obtained at reduced costs, opening the possibility to compete with the chromatographic methods generally used for this analysis.

Electroanalytical study of fluvoxamine

Fluvoxamine (FVX) can be reduced at a mercury-drop electrode, with a maximum peak current intensity being obtained at a potential of -0.7 V vs. Ag/AgCl, in an aqueous electrolyte solution of pH 2. The compound was determined in a pharmaceutical product and in spiked human serum by square-wave adsorptive-stripping voltammetry (SWAdSV) after accumulation at the electrode surface, under batch conditions. Because the presence of dissolved oxygen did not interfere significantly with the analysis, it was also possible to determine FVX in the pharmaceutical product by use of a flow-injection analysis (FIA) system with SWAdSV detection. The methods developed were validated and successfully applied to the quantification of FVX in a pharmaceutical product. Recoveries between 76 and 89% were obtained in serum analysis. The FIA-SWAdSV method enabled analysis of up to 120 samples per hour at reduced cost, implying the possibility of competing with the chromatographic methods usually used for this analysis.