A Comparison Study of the Interaction of Progesterone and Testosterone Drugs with Human Serum Albumin: A Fluorescence Quenching Study

The interaction of steroid hormones (testosterone and progesterone) with human serum albumin in phosphate buffer at pH 7.5 and at 25 C have been studied using a fluorescence spectrophotometer. The results showed that fluorescence emission spectra were quenched with the increase of steroid molar ratios in fixed amount of HSA. The result indicated that progesterone and testosterone hormones have an ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. Two mathematical models Stern–Volmer and Scatchard for analysis of fluorescence spectra were used. Progesterone binding to HSA was increased by a factor of 2.6 greater than that detected for the interaction of testosterone with HSA. The values of Stern-Volmer constants were determined to be (2.0× 104 L mol-1) for progesterone–HSA complex and (7.7× 103 L mol-1) for testosterone–HSA complex, Respectively. Whereas, the Scatchard constants were (2.1× 104 L mol-1) and (7.9× 103 L mol-1) for progesterone–HSA and testosterone–HSA complexes, respectively

Thermodynamic Properties of Hydrogen Peroxide Binding to Bovine Liver Catalase

Catalase [CAT: EC 1.11.16] was purified from bovine liver using cellulose affinity chromatography and some enzyme characteristics were investigated. The interaction of H2O2 with catalase was investigated by fluorescence spectroscopy, and the change in intrinsic fluorescence intensity at 435 nm was used to estimate the association constant of the interaction. The binding process resulted in a change in the intrinsic fluorescence. The emission spectra were analyzed according to a model described by Chipman et al., to obtain the association constant (ka ) values in the temperature range of 25-50 ?C. The results showed that the association constants were temperature dependent. The value of Ka at 25°C was 2.4 × 105 M –1. Moreover, the thermodynamic parameters for the interaction H2O2/BLC were obtained from Van't Hoff plot. The results indicated that the interaction was enthalpically driven accompanied by negative entropic contribution in the studied temperature range. The association constant values were determined from Van't Hoff plots. Key words: Bovine liver catalase, fluorescence emission, association constants, thermodynamic parameters, Chipman model

Complexation and thermodynamic studies of polysiloxane iminobis (N-diethylenediamineacetamide) ligand system with some transition metal ions

Many research concerning the synthesis of insoluble polysiloxane immobilized ligand systems, have been reported [1-21]. These functionalized polysiloxanes have been prepared by two methods. The first method; using the sol-gel process by hydrolytic polycondensation of tetraethylorthosilicate (TEOS) and the appropriate silane coupling agent (RO) 3 SiX, where X= ligand group)[1, 2]. The second method is by modification of a pre-prepared polysiloxane with a silane coupling agent containing the appropriate functional group [13-21]. These hybrid materials show high thermal, hydrolytic and mechanical stability over the organic polymers [5, 6]. These polysiloxane immobilized ligand systems have several applications such as extraction, recovery and separation of metal ions [13-21]. They also used as supports for heterogeneous catalysis and chromatography [2, 11, 22]. These materials have been characterized recently by many techniques including high-resolution solid state NMR [23-26], XPS analysis and thermal analysis [27-35]. In this work iminobis (N-diethylenediamineacetamide) polysiloxane-immobilized ligand system was prepared as previously reported [36] and complexed with Co2+, Ni2+ and Cu2+ metal ions from aqueous solutions. This study may be useful because the selection and separation of the chelating functionalized ligand system closely related to the stability of the complexes formed

New room temperature ionic liquids with interesting ecotoxicological and antimicrobial properties

A new set of room temperature ionic liquids (RTIL), tetrabutylammonium (TBA) salts: formate, acetate, propionate, butyrate, benzoate, nitrobenzoate, cinnamate, salicylate, sulfanilate, linoleate, and oleate, were prepared by neutralization of tetrabutylammonium hydroxide (TBA OH) and the corresponding acid. The compounds showed interesting chemical and biological properties. They are soluble in water and organic solvents producing conducting solutions and are effective against certain Gram-negative as well as Gram-positive bacteria. Notably, they affected some proteins such as bovine serum albumin (BSA) and catalase (CAT) as inferred by following the fluorescence emission spectra

Ionic liquids: Industrial applications to green chemistry.

Active Pharmaceutical Ingredients-Ionic Liquids (APIs-ILs), when compared to Active Pharmaceutical Ingredients Hydrochloride (APIs-HCl), exhibits modified solubility, increased thermal stability and significant enhancement in the efficiency of APIs. To produce and demonstrate application of green ionic liquid form of the APIs, we prepared ammonium, phosphonium and choline couple with flufenamic acid. Their physical properties such as thermal stability, melting points and solubility were studied. Flufenamic ionic liquids undoubtedly represent a promising group of ionic liquids. As these new ionic liquids are halogen–free, it is expected that such new compounds will prove useful in further studies centered on active pharmaceutical ingredients ionic liquids