Spectroscopic and molecular modeling studies of binding interaction between bovine serum albumin and roflumilast.

BACKGROUND: The binding interaction between bovine serum albumin (BSA) and roflumilast (ROF) was explored in this study. The binding of drugs to albumin plays a vital role in their pharmacokinetics and pharmacodynamics in vivo. The mechanisms involved in the interaction between BSA and ROF was studied using multi-spectroscopic experimental and computational approaches. MATERIALS AND METHODS: Spectrofluorometric experiments were used to determine the method of quenching involved and the conformational changes in the BSA. UV-visible spectroscopy synchronous and three-dimensional fluorescence spectroscopy were used to further explore the binding interaction mechanism. RESULTS: The results suggested that the intrinsic fluorescence of BSA was quenched due to the formation of a static complex between ROF and BSA. Conformational changes in BSA were determined based on its interaction with ROF. The thermodynamic results suggested that the interaction between ROF and BSA was spontaneous and a hydrophobic interaction occurred between them. Site I of BSA was suggested as the site of interaction between ROF and BSA based on the site marker experiments. CONCLUSION: The molecular simulation results and the experimental outcomes were complimentary to each other and helped to identify the binding site and nature of bonds involved in the interaction between ROF and BSA.

Potentiating and synergistic effect of grapefruit juice on the antioxidant and anti-inflammatory activity of aripiprazole against hydrogen peroxide induced oxidative stress in mice.

BACKGROUND: Dependence on antipsycotic drugs like aripriprazole (ARI) is increasing at alarming rate, hence, this study was undertaken to support the hypothesis that supplementation of Citrus paradisi (Grapefruit) juice having high concentration of polyphenols might potentiate and synergize the therapeutic effect of ARI, by increasing its bioavailability and inherent antioxidant potential. These benefits together might decrease the daily dosage of the ARI and thus alleviate the possible side effects of drug. METHODS: In this study the antioxidant and anti-inflammatory potential of ARI alone and in combination with GFJ was evaluated for hydrogen peroxide (H2O2) induced oxidative stress in mice. Seventy mice (4 weeks old), were randomly divided into seven groups. Group I: Control; Group II: H2O2 treated; Group III; ARI treated; Group IV GFJ treated; Group V: GFJ and H2O2 treated; Group VI; ARI and H2O2 treated; Group VII; ARI, GFJ and H2O2 treated. Serum levels of alanine aminotransferase (ALT), blood urea nitrogen (BUN), creatinine kinase (CK), creatinine and total protein were measured. Furthermore, pro-inflammatory cytokines Interleukin (IL)-1α, IL-2, IL-10 and tumor necrosis factor-α (TNF-α) concentrations were also measured. RESULTS: The mice group that was treated with ARI, GFJ or combination of the two showed significant improvement in the H2O2 altered parameters with the combination group showing more significant improvement than the ARI and GFJ alone groups indicating a synergistic and potentiating effect of the antioxidant and anti-inflammatory potential of GFJ on ARI. CONCLUSION: Supplementing GFJ to ARI might increase an anti-oxidative potential of ARI due to inherent antioxidant and anti-inflammatory activity of GFJ and thus could alleviate the possible dosage dependent side effects of ARI.

Study of the Interactions of Bovine Serum Albumin with the New Anti-Inflammatory Agent 4-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)-N'-[(4-ethoxy-phenyl)methylidene]benzohydrazide Using a Multi-Spectroscopic Approach and Molecular Docking.

The lipophilic derivative of thalidomide (4-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)-N'-[(4-ethoxyphenyl)methylidene]benzohydrazide, 6P) was synthesized to enhance its characteristics and efficacy. Earlier studies have proved the immunomodulatory and anti-inflammatory effects of 6P. In this study the interaction between bovine serum albumin (BSA) and 6P was studied using a multi-spectroscopic approach which included UV spectrophotometry, spectrofluorimetry and three dimensional spectrofluorometric and molecular docking studies. Static quenching was involved in quenching the fluorescence of BSA by 6P, because a complex formation occurred between the 6P and BSA. The binding constant decreased with higher temperature and was in the range of 2.5 × 105-4.8 × 10³ L mol-1 suggesting an unstable complex at higher temperatures. A single binding site was observed and the the site probe experiments showed site II (sub-domain IIIA) of BSA as the binding site for 6P. The negative values of ∆G°, ∆H° and ∆S° at (298/303/308 K) indicated spontaneous binding between 6P and BSA as well as the interaction was enthalpy driven and van der Waals forces and hydrogen bonding were involved in the interaction. The docking results and the results from the experimental studies are complimentary to each other and confirm that 6P binds at site II (sub-domain IIIA) of BSA.

Losartan: Comprehensive Profile.

Losartan (Cozaar™) is an angiotensin II receptor antagonist with antihypertensive activity. It is used in the management of hypertension and heart failure. Nomenclature, formulae, elemental analysis, and appearance of the drug are included in this review. The uses, applications, and the variety of synthetic pathways of this drug are outlined. Physical characteristics including: ionization constant, solubility, X-ray powder diffraction pattern, thermal methods of analysis, UV spectrum, IR spectrum, mass spectrum with fragmentation patterns, and NMR (1H and 13C) spectra of losartan together with the corresponding figures and/or tables are all produced. This profile also includes the monograph of British Pharmacopoeia, together with several reported analytical methods including: spectrophotometric, electrochemical, chromatographic, and capillary electrophoretic methods. The stability, the pharmacokinetic behavior and the pharmacology of the drug are also provided.

A novel analytical approach for reducing the consumption of organic solvents in the charge transfer-based spectrophotometric analysis: application in the analysis of certain antihypertensive drugs.

The present study describes the development of a novel analytical approach that can reduce by 50-fold the consumption of organic solvents in the charge transfer (CT)-based spectrophotometric analysis. The proposed approach employed 96-microwell assay plates for carrying out the reaction. The CT reaction between the electron-donating analyte and electron-accepting reagent was performed in microwells (200-µL of organic solvent) and the color signals were measured with a microwell-plate reader. Optimum conditions for the proposed approach were established for two antihypertensive drugs, namely ramipril (RML) and lisinopril (LSL) as model compounds for the electron-donating analytes, and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as a π-electron acceptor. Under the optimum conditions, Beer's law was obeyed in the concentration range of 6-100 and 6-60 µg mL-1 for RML and LSL, respectively. The limits of detection were 0.97 and 1.10 µg mL-1 for RML and LSL, respectively. The precision of the methods was satisfactory; the values of relative standard deviations did not exceed 1.1 %. The proposed approach was successfully applied to the analysis of pharmaceutical dosage forms with good accuracy and precision. The results were comparable with those of the reported methods. The approach described herein is of great practical value in pharmaceutical analysis because it reduces the exposure of analysts to the toxic effects of organic solvents, lowers the analysis cost by 50-fold, and it has a high throughput property. Although the approach was validated for RML and LSL, the same methodology could be used for any electron-donating analyte for which a CT-reaction can be performed.

A highly sensitive enzyme immunoassay for evaluation of 2'-deoxycytidine plasma level as a prognostic marker for breast cancer chemotherapy.

A highly sensitive competitive enzyme immunoassay (EIA) has been developed and validated for the determination of the plasma level of 2'-deoxycytidine (dCyd), the potential prognostic marker for breast cancer chemotherapy. This assay employed a monoclonal antibody that recognizes dCyd with a high specificity, and 5'-succinyl-dCyd (5'sdCyd) conjugate of bovine serum albumin (5'sdCyd-BSA) immobilized onto microplate wells as a solid phase. The assay involved a competitive binding reaction between dCyd, in plasma sample, and the immobilized 5'sdCyd-BSA for the binding sites of the anti-dCyd antibody. The bound antibody was quantified with horseradish peroxidase-labeled anti-immunoglobulin second antibody and 3,3',5,5'-tetramethylbenzidine as a peroxidase substrate. The concentration of dCyd in the sample was quantified by its ability to inhibit the binding of the antibody to the immobilized 5'sdCyd-BSA and subsequently the color formation in the assay. The assay limit of detection was 8 nM and the effective working range at relative standard deviations (R.S.D.s) of