Estandarización de un método por HPLC para cuantificar diclofenaco en muestras de microdiálisis mediante fotoderivatización precolumna / Standardization of a HPLC method for quantitation of diclofenac in microdialysis samples through precolumn photoderivatization

Introducción: la cuantificación del diclofenaco en muestras de pequeño volumen y baja concentración de analito es compleja y requiere de un método analítico sencillo, altamente sensible y reproducible. Objetivo: estandarizar un método por cromatografía líquida de alta resolución (HPLC) con fotoderivatización precolumna, para cuantificar diclofenaco en muestras de pequeño volumen y baja concentración de analito. Métodos: se obtuvieron los fotoproductos del diclofenaco mediante irradiación de muestras a l= 254 nm en celdas de cuarzo, politetrafluoroetileno (PTFE) y polivinilcloruro (PVC), colocadas en diferentes posiciones del área de irradiación durante 6, 24 y 60 min respectivamente. Para la separación de los fotoproductos se utilizó una columna C-18 Agilent Eclipse Plus (5 µm; 150 mm; 4,6 µm id.), usando como fase móvil acetonitrilo (ACN): agua, acidulada con ácido fosfórico hasta pH= 3,0 en diferentes proporciones hasta encontrar la óptima; la temperatura empleada fue de 30 °C, el flujo de 1 mL/min y el volumen de inyección de 20 µL. Se detectaron los fotoproductos por fluorescencia a lambas de excitación y emisión de 286 y 360 nm respectivamente. Resultados: la fotodegradación del diclofenaco en celdas de PTFE ocurrió en 6 min cuando se irradiaron soluciones a 254 nm en el centro del área de irradiación. La separación de los tres fotoproductos principales se logró utilizando una fase móvil ACN: agua, acidulada con ácido fosfórico hasta pH= 3,0; 65:35. El fotoproducto que eluye a 3,4 min se produjo en concentraciones altas y estables las cuales presentaron una tendencia lineal en un gráfico de respuesta del equipo (área) vs. concentración de diclofenaco en un rango entre 1,25-500 ng/mL. Conclusiones: se logró estandarizar un método por HPLC para la cuantificación de diclofenaco presente en muestras de pequeño volumen y baja concentración, el cual podrá someterse a proceso de validación(AU)

Introduction: the diclofenac quantitation in small volume and low analyte concentration samples is complex and requires a simple, highly sensitive and reproducible analytical method. Objective: to standardize a high performance liquid chromatography with precolumn photoderivatization to quantitate diclofenac in small volume and low analyte concentration samples. Methods: diclofenac photoproducts were obtained by irradiating samples at l= 254 nm in quartz polytetrafluoroethylene (PTFE) and polyvinyl chloride (PVC) cells placed in different positions of the irradiation area for 6, 24 and 60 minutes respectively. For the separation of photoproducts, a C-18 Agilent Eclipse Plus column (5 µm, 150 mm; 4.6 µm id.) was used, with a mobile phase containing a mixture of acetonitrile and water pH 3.0 adjusted with ortho-phosphoric acid, in different proportions until the optimal one was found; the flow rate of mobile phase was 1.0 mL/min with column temperature of 30 °C. The sample injection volume was 20 µL. Photoproducts were detected through fluorescence with excitation and emission wavelength at 286 and 360 nm respectively. Results: diclofenac photodegradation in PTFE cells occurs within 6 minutes when solutions are irradiated at 254 nm in the central part of the irradiation area. The separation of the three major photoproducts was accomplished using a mobile phase of acetonitrile: water adjusted with ortho-phosphoric up to pH= 3.0;65:35. The photoproduct at 3.4 minutes was eluted at high stable concentrations, with a linear trend presented in an area graph versus diclofenac concentration in the range of 1.25-500 ng/mL. Conclusions: a new HPLC-method for quantitation of diclofenac in small volume and low concentration samples was standardized; it may undergo validation process(AU)

Molecular docking studies of withanolides against Cox-2 enzyme

Withaniasomnifera [Ashwaganda] belonging to the family solanaceae is the subject of our present study. Withanoloides which are the major chemical constituents have been proved of interest because of their structural variations in the hybrids of different races. Docking is the process which brings the two structures together. In the present study we focus the extensive use of tool and graphical software for the identification of the binding energy of selected Withanolides like Withaferin -A, Withanolide-D from Withaniasomnifera and to screen the phytoconstituents that will dock/bind to the active sites of COX-2 enzyme. The relief from the symptoms of inflammation and pain can be by the Pharmacological inhibition of COX which involves the prediction of potential ligand for the treatment of inflammation. The energy value of docking between the target and the phytoconstituents under investigation and comparison with Diclofenac sodium was taken into consideration for coming into conclusion regarding the best pose and the binding ability

Simultaneous determination of some pharmaceuticals in hospital effluents Using HPLC with UV and fluorescence detectors

The development and validation of an HPLC/UV/Fluorescence [FL] detection method is described, which enables the measurement of the most consumed pharmaceuticals [methotrexate, caffeine, diclofenac, glimepiride and ibuprofen] in Jordanian hospital effluents. Separation was done on a RP-C8 column at a flow rate of 1 ml/min using 1:1 H2O/acetonitrile with 0.1% trifluoroacetic acid. The samples [200 ml each] were extracted and cleaned-up on C18 cartridges. Correlation coefficients of the pharmaceuticals calibration were higher than 0.997 using a UV detector and 0.996 using a fluorescence detector for methotrexate. Recoveries were ranged from 87% to 108.3%

Fabrication of potential macromolecular prodrugs of aspirin and diclofenac with dextran

Aspirin and diclofenac conjugates with dextran were synthesized as potential macromolecular prodrugs under homogeneous reaction conditions by using 4-methyl-benzenesulfonyl chloride as an acylating agent in the presence of triethylamine as a base. Highly pure conjugates with good yields were synthesized by this acylation method. All of the products were found soluble in aqueous medium as well as in dimethylsulfoxide and N, N-dimethylacetamide. The UV/Vis spectrophotometry has indicated the incorporation of drugs in conjugates and extent of substitution of drug onto dextran polymer. Covalent attachment of the drug onto the drug carrier polymer [dextran] was verified by [1]H NMR and Fourier transform infrared [FTIR] spectroscopic analysis. The prodrugs were analysed by powder X-ray diffraction [XRD] measurements. Phase changes were noticed by powder XRD for all macromolecular prodrugs indicating the change of state of matter towards more crystallinity. Therefore, fabricated macromolecular prodrugs are potential candidates to show better pharmacokinetic profile. All of the products were thoroughly characterized by using different spectroscopic techniques

Effect of processing variables on micro particulate system of aceclofenac

Microparticulate systems of aceclofenac were prepared by modified solvent evaporation method using different variables such as polymer [cellulose acetate]: drug ratios [1:9, 1:6, 1:3, and 1:1], agitation speeds [500-1500 rpm] and stirring time [5-15 min]. The effects of processing variables were evaluated by microparticle size and entrapment efficiency. The average microparticle size increases from 80.2 +/- 1.45 to 97.3 +/- 2.06