New Spectrophotometric and Fluorimetric Methods for Determination of Fluoxetine in Pharmaceutical Formulations

New simple and sensitive spectrophotometric and fluorimetric methods have been developed and validated for the determination of fluoxetine hydrochloride (FLX) in its pharmaceutical formulations. The spectrophotometric method was based on the reaction of FLX with 1,2-naphthoquinone-4-sulphonate (NQS) in an alkaline medium (pH 11) to form an orange-colored product that was measured at 490 nm. The fluorimetric method was based on the reaction of FLX with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in an alkaline medium (pH 8) to form a highly fluorescent product that was measured at 545 nm after excitation at 490 nm. The variables affecting the reactions of FLX with both NQS and NBD-Cl were carefully studied and optimized. The kinetics of the reactions were investigated, and the reaction mechanisms were presented. Under the optimum reaction conditions, good linear relationships were found between the readings and the concentrations of FLX in the ranges of 0.3–6 and 0.035–0.5 μg mL−1 for the spectrophotometric and fluorimetric methods, respectively. The limits of detection were 0.1 and 0.01 μg mL−1 for the spectrophotometric and fluorimetric methods, respectively. Both methods were successfully applied to the determination of FLX in its pharmaceutical formulations

Simple Spectrophotometric Method for Determination of Paroxetine in Tablets Using 1,2-Naphthoquinone-4-Sulphonate as a Chromogenic Reagent

Simple and rapid spectrophotometric method has been developed and validated for the determination of paroxetine (PRX) in tablets. The proposed method was based on nucleophilic substitution reaction of PRX with 1,2-naphthoquinone-4-sulphonate (NQS) in an alkaline medium to form an orange-colored product of maximum absorption peak (λmax) at 488 nm. The stoichiometry and kinetics of the reaction were studied, and the reaction mechanism was postulated. Under the optimized reaction conditions, Beer's law correlating the absorbance (A) with PRX concentration (C) was obeyed in the range of 1–8 μg mL−1. The regression equation for the calibration data was: A = 0.0031 + 0.1609 C, with good correlation coefficients (0.9992). The molar absorptivity (ε) was 5.9 × 105 L mol−1 1 cm−1. The limits of detection and quantitation were 0.3 and 0.8 μg mL−1, respectively. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 2%. The proposed method was successfully applied to the determination of PRX in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was 97.17 ± 1.06 %. The results obtained by the proposed method were comparable with those obtained by the official method

HEPATOPROTECTIVE AND HEPATOTHERAPUTIC EFFECTS OF PROPOLIS AGAINST D-GALACTOSAMINE/LIPOPOLYSACCHARIDE-INDUCED LIVER DAMAGE IN RATS

Objective: The aim of the present study was to investigate the potential hepatoprotective and hepatotherapeutic activities of propolis against D-galactosamine and lipopolysaccharide (D-GaIN/LPS)-induced hepatotoxicity in rats.Methods: Hepatotoxicity was induced in rats by intra peritoneal injection of GalN (300 mg/kg) and LPS (30 μg/kg). In the hepatoprotection experiment, propolis was administered orally for 10 days before induction of hepatoxicity. In another experiment (hepatotherapy), propolis was dosed immediately after GalN/LPS injection.Results: Injection of GalN/LPS to rats induced hepatic damage that was manifested by a significant increase in the activities of aminotransferases, alkaline phosphatase, lactate dehydrogenase and levels of tumor necrosis factor-alpha (TNF-α) and total bilirubin in serum. Liver homogenate of intoxicated animals had the lower content of reduced glutathione with increased levels of the hepatic malondialdehyde and caspase-3 enzyme. Histological data presented marked damage in liver sections of intoxicated rats. Oral dosing of propolis before or once immediately after intoxication reversed these altered parameters near to normal values.Conclusion: Liver apoptotic events such as DNA fragmentation and increased caspase-3 activity observed during intoxication were prevented by pre and post- propolis treatment. These results suggest that propolis could afford significant protection and therapy in alleviation of hepatotoxicity.Â

Oil spill sorption using carbonized pith bagasse: trial for practical application

In the present work, an attempt was made to provide an efficient, easily deployable method of cleaning up oil spills and recovering of the oil. Carbonized pith bagasse, a relatively abundant and inexpensive material is currently being investigated as an adsorbent to remove contaminants "oil" from water. Fibers extracted from bagasse and carbonized at 300 °C were found to have a high performance for sorption and recovery of light, heavy oils and even the viscous ones. The physical properties of pith bagasse were investigated using scanning electronic microscope to show the inner and the outer surface and the cross section area of the pith bagasse and thermo gravimetric analyzer to investigate the degradation profile of the pith bagasse. The carbonized pith bagasse was packed into a polypropylene bag and its sorption behavior was studied. A comparison was made between the prepared pad and the commercial sorbents show that the pad containing carbonized pith bagasse has higher sorption capacity in comparison to the commercial sorbents. The pad exhibited high oil retention ability and a high selectivity for the oils over the water. The pad showed a possibility of reuse for eight times. The sorption capacity of the pads containing carbonized pith bagasse was found to increase with increasing the time of sorption till it reaches the maximum value at the time of sorption equal to 60 min

Spectrophotometric study for the reaction between fluvoxamine and 1,2-naphthoquinone-4-sulphonate: Kinetic, mechanism and use for determination of fluvoxamine in its dosage forms.

Spectrophotometric study was carried out, for the first time, to investigate the reaction between the antidepressant fluvoxamine (FXM) and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. In alkaline medium (pH 9), an orange-colored product exhibiting maximum absorption peak (lambda(max)) at 470nm was produced. The kinetics of the reaction was investigated and its activation energy was found to be 2.65kcalmol(-1). Because of this low activation energy, the reaction proceeded easily. The stoichiometry of the reaction was determined and the reaction mechanism was postulated. This color-developing reaction was successfully employed in the development of simple and rapid spectrophotometric method for determination of FXM in its pharmaceutical dosage forms. Under the optimized reaction conditions, Beer's law correlating the absorbance (A) with FXM concentration (C) was obeyed in the range of 0.6-8mugml(-1). The regression equation for the calibration data was A=0.0086+0.1348C, with good correlation coefficient (0.9996). The molar absorptivity (varepsilon) was 5.9x10(4)lmol(-1)cm(-1). The limits of detection and quantification were 0.2 and 0.6mugml(-1), respectively. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 2%. The proposed method was successfully applied to the determination of FXM in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was 100.47+/-0.96%. The results obtained by the proposed method were comparable with those obtained by the official method. The proposed method is superior to all the previously reported spectrophotometric methods for determination of FXM in terms of its simplicity and sensitivity. The method is practical and valuable for its routine application in quality control laboratories for analysis of FXM

A comparative study of the novel spectrophotometric methods versus conventional ones for the simultaneous determination of Esomeprazole magnesium trihydrate and Naproxen in their binary mixture

Two novel simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra are developed and validated for simultaneous determination of Esomeprazole magnesium trihydrate (ESO) and Naproxen (NAP) namely; absorbance subtraction and ratio difference. The results were com- pared to that of the conventional spectrophotometric methods namely; dual wavelength and isoabsorp- tive point coupled with first derivative of ratio spectra and derivative ratio. The suggested methods were validated in compliance with the ICH guidelines and were successfully applied for determination of ESO and NAP in their laboratory prepared mixtures and pharmaceutical preparation. No preliminary separation steps are required for the proposed spectrophotometeric procedures. The statistical compar- ison showed that there is no significant difference between the proposed methods and the reported method with respect to both accuracy and precision

Characterization of in vivo metabolites in rat urine following an oral dose of masitinib by liquid chromatography tandem mass spectrometry

Abstract Masitinib (MST) is an orally administered drug that targets mast cells and macrophages, important cells for immunity, by inhibiting a limited number of tyrosine kinases. It is currently registered in Europe and USA for the treatment of mast cell tumors in dogs. AB Science announced that the European Medicines Agency has accepted a conditional marketing authorization application for MST to treat amyotrophic lateral sclerosis. In our work, we focused on studying in vivo metabolism of MST in Sprague–Dawley rats. Single oral dose of MST (33 mg kg−1) was given to Sprague–Dawley rats (kept in metabolic cages) using oral gavage. Urine was collected and filtered at 0, 6, 12, 18, 24, 48, 72 and 96 h from MST dosing. An equal amount of ACN was added to urine samples. Both organic and aqueous layers were injected into liquid chromatography-tandem mass spectrometry (LC–MS/MS) to detect in vivo phase I and phase II MST metabolites. The current work reports the identification and characterization of twenty in vivo phase I and four in vivo phase II metabolites of MST by LC–MS/MS. Phase I metabolic pathways were reduction, demethylation, hydroxylation, oxidative deamination, oxidation and N-oxide formation. Phase II metabolic pathways were the direct conjugation of MST, N-demethyl metabolites and oxidative metabolites with glucuronic acid. Part of MST dose was excreted unchanged in urine. The literature review showed no previous articles have been made on in vivo metabolism of MST or detailed structural identification of the formed in vivo phase I and phase II metabolites

Liquid chromatography tandem mass spectrometry method for the quantification of vandetanib in human plasma and rat liver microsomes matrices: metabolic stability investigation

Abstract Vandetanib (VNT) is a new oral tyrosine kinase inhibitor that acts mainly by inhibiting vascular endothelial growth factor receptor (VEGFR). Fast, specific, sensitive and validated LC–MS/MS was established for the determination of VNT in two various matrices including rat liver microsomes (RLMs) and human plasma. This method was applied in metabolic stability investigation of VNT. Resolution of two analytes was performed using C18 column and isocratic mobile phase composed of binary system of 10 mM ammonium formate (pH 4.1) and acetonitrile in a ratio of 1:1. The flow rate was set at 0.25 mL/min and total run time was 4 min with injection volume of 5 µL. Ions were generated by ESI source and analyzed by multiple reaction monitoring mode (basis for quantification) in the Agilent 6410 QqQ analyzer. The linearity of the established method ranged from 5 to 500 ng/mL (r2 ≥ 0.9996) in human plasma and RLMs. LOQ and LOD were 2.48 and 7.52 ng/mL, and 2.14 and 6.49 in human plasma and RLMs matrices. The intra-day and inter-day precision and accuracy were 0.66–2.66% and 95.05–99.17% in human plasma matrix while in RLMs matrix, ranged from 0.97 to 3.08% and 95.8 to 100.09%, respectively. In vitro half-life was 39.85 min and intrinsic clearance was 3.92 ± 0.28 mL/min/kg

LC–MS/MS method for the quantification of masitinib in RLMs matrix and rat urine: application to metabolic stability and excretion rate

Abstract Masitinib (MST) is a selective tyrosine kinase inhibitor. Validated liquid chromatography tandem mass spectrometric method (LC–MS/MS) was developed for the quantification of MST in rat liver microsomes (RLMs) matrix. The developed method was applied to metabolic stability and excretion rate studies. Reversed phase liquid chromatography was used for resolution of MST and bosutinib (IS) using C18 (50 mm × 2.1 mm, 1.8 μm). Binary solvent system consisted of 35% solvent A (0.1% formic acid in H2O, pH: 3.2) and 65% solvent B (acetonitrile) used as mobile phase at flow rate of 0.25 mL with a total run time of 5 min. Injection volume was 5 µL. Generation of ions was done in positive ESI source and quantification of MST and IS were done using MRM mode. The developed method showed a linearity in the range of 5–200 ng/mL (r2 ≥ 0.9992) with LOQ and LOD of 0.25 and 0.76 ng/mL in RLMs. The intra- and inter-day precision and accuracy ranged from 0.95 to 1.49 and − 5.22 to 1.13%, respectively in RLMs. Rate of disappearance of MST during incubation with RLMs was almost linear allover incubation time. In vitro t1/2 was 50.38 min and CLin was 3.11 ± 0.2. The developed method was applied also to measure the rate of masitinib excretion in rat urine. The method can used for further pharmacokinetic studies of MST