scholarly journals Sensitization of Eriochromeazurol-B in Presence of Cetyldimethylethylammonium Bromide for the Microdetermination of Some Lanthanides

2012 ◽  
Vol 9 (4) ◽  
pp. 2394-2406 ◽  
Author(s):  
Anil B. Zade ◽  
Pawan P. Kalbende ◽  
Mayuri S. Umekar ◽  
Gajanan W. Belsare

Cetyldimethylethylammonium bromide, a cationic surfactant has been used to decolorize eriochromeazurol B, an anionic triphenylmethane type of dye. Addition of specific lanthanide metal ion to this decolorized solution resulted into intense colored stable ternary complex with large bathochromic shift from 540 nm (binary complex) to 650 nm (ternary complex) with increase in absorbance values at shifted wavelength. CDMEAB thus decreases the color intensity of ECAB and increases the absorbance value of ternary complexes. This two fold advantage resulted into enhancement in molar absorptivities and sensitivities at shifted wavelength of ternary complexes with stoichiometric composition 1:(1:3)2, [Ln : (R:S)] for all lanthanides understudy namely yttrium, neodymium, europium, terbium and ytterbium. The ternary complexes at pH 6.0 exhibited absorption maxima at 650 nm with molar absorptivities 69000 L.mol-1.cm-2for Y(III), 66000 L.mol-1.cm-2for Nd(III), 69000 L.mol-1.cm-2for Eu(III), 64000 L.mol-1.cm-2for Tb(III), 70000 L.mol-1.cm-2for Yb(III). Beer's law were obeyed in concentration range 0.11-0.94, 0.19-1.53, 0.2-1.41, 0.21-1.69 and 0.23-1.11 ppm for Y(III), Nd(III), Eu(III), Tb(III) and Yb(III) respectively. Conditional formation constants and various analytical parameters have been evaluated and compared the results of newly formed ternary complexes with binary complexes. Finally newly suggested modified method have been recommended for the microdetermination of lanthanides understudy.

1993 ◽  
Vol 58 (5) ◽  
pp. 1103-1108 ◽  
Author(s):  
Mohamed M. Shoukry ◽  
Eman M. Shoukry

The formation constants of the binary and ternary complexes of palladium(II) with diethylenetriamine and amino acids as ligands have been determined potentiometrically at 25 °C in 0.1 M NaNO3 solution. The relative stability of each ternary complex was compared with that of the corresponding binary complexes in terms of ∆logK values. The mode of chelation was ascertained by conductivity measurements.


2000 ◽  
Vol 165 (2) ◽  
pp. 253-260 ◽  
Author(s):  
JJ Bond ◽  
S Meka ◽  
RC Baxter

Many tumours secrete IGF-II in incompletely processed precursor forms. The ability of these pro-IGF-II forms to complex with the six IGF binding proteins (IGFBPs) is poorly understood. In this study, pro-IGF-II has been extracted from the serum and tumour tissue of two patients with non-islet cell tumour hypoglycaemia. These samples were used to study binary complex formation with IGFBPs-1 to -6 using competitive IGF-II binding assays and ternary complex formation with IGFBP-3 and IGFBP-5. In each case, IGFBPs-1 to -6 showed little difference in their ability to form binary complexes with recombinant IGF-II or tumour-derived pro-IGF-II forms, when the preparations were standardised according to IGF-II immunoreactivity. As previously described, ternary complex formation by acid-labile subunit (ALS) with IGFBP-3 and pro-IGF-II was greatly decreased compared with complex formation with mature IGF-II. In contrast, ALS bound similarly to IGFBP-5 in the presence of pro-IGF-II and mature IGF-II. These studies suggest that pro-IGF-II preferentially forms binary complexes with IGFBPs, and ternary complexes with IGFBP-5, rather than ternary complexes with IGFBP-3 as seen predominantly in normal serum. This may increase the tissue availability of serum pro-IGF-II, allowing its insulin-like potential to be realised.


2011 ◽  
Vol 8 (3) ◽  
pp. 1132-1141 ◽  
Author(s):  
A. B. Upase ◽  
A. B. Zade ◽  
P. P. Kalbende

Cationic surfactant, cetyldimethylethylammonium bromide (CDMEAB), sensitize the color reactions of Th(IV) and U(VI) with chrome azurol-S(CRAS). Formation of water soluble deeply colored ternary complexes of metal ions show large bathochromic shift. Same stoichiometric composition of ternary complexes with 1:2:4 molar ratio (M-CRAS-CDMEAB) have been observed for both the metal ions and are responsible for enhancement in molar absorptivities and sensitivities at shifted wavelength. The ternary complexes of thorium(IV) and uranium(VI) exhibit absorption maxima at 640 and 620 nm with molar absorptivities 85500 and 69600 L.mol-1.cm-2respectively. Beer’s law were obeyed in concentration range 0.12-0.185 ppm for Th(IV) and 0.13-0.162 ppm for U(VI) in presence of CDMEAB. Conditional formation constants and various analytical parameters have been evaluated and compared the results of binary and ternary complexes. Enhancement in the molar absorptivities in presence of CDMEAB clearly indicated the usefulness of these colored reactions for microdetermination.


Author(s):  
Mohammed Jafar ◽  
Sadath Ali ◽  
Hassan Ghonaim

The aim of the presentstudy wasto improve the aqueous solubility and dissolution rate of a BCS Class-IIdrug,ketoprofen by β-cyclodextrin ternary complexes incorporating hydrophilic polymers polyethylene glycol 6000 (PEG6000) and polyvinyl pyrrolidone (PVP). Initially,ketoprofen (KPF)binary complexes with β-Cyclodextrin (βCD)wereformulated by physical mixing,co-grinding, and solvent evaporation methods which was followed by ternary complex formulation of selected KPF-βCD binary complex incorporatingPEG6000 and PVP.The solvent evaporation method was used in the formulation of ternary complexesof ketoprofen, sincein the beginning of this study, it was proved to be the best methodcomparatively in yielding promising binary complexes of ketoprofen.Ketoprofen formed 1:1 M stoichiometric binary and ternary inclusion complexes as demonstrated by the AL-type of phase solubility graph. An increase in the stability constant value (Kc) of KPF- βCD complex in the presence of PEG6000 and PVP conceded higher complexation competency. FTIR and SEM studies evidenced the perfect ternary inclusion complex formation. Ternary complexes showed improved drug dissolution compared with Ketoprofenalone and KPF-βCD binary complex. The ternary complex containg 1:1:2 molar ratio of KPF:βCD:PEG6000exhibited 94.24% drug dissolution in 2 hours, which was significantly high in relation to ternary complexes containg PVPand it was found to follow first order release mechanism. Complex studied for stabilityshowed no significant change in physical appearance, drug content and drug dissolution characteristic indicating high stability.


Author(s):  
Jafar M. ◽  
Salahuddin M. ◽  
Kayed T. S. ◽  
Ahmad N M. ◽  
Al-Eid H. A. ◽  
...  

The present study was aimed to improve the aqueous solubility and dissolution rate of an NSAID meloxicam by hydroxy propyl β-cyclodextrin ternary complexes employing ethanolamines. Initially, meloxicam (MLX) binary complexes with Hydroxy propyl β-Cyclodextrin (HPβCD) were formulated by kneading and solvent evaporation techniques which was followed by ternary complex preparation of selected MLX-HPβCD binary complex employing different ethanolamines by solvent evaporation method. The solvent evaporationwas used in preparing ternary complexes of MLX, because it was proved to be the best method comparatively in yielding promising binary complexes of meloxicam in the initial stage of this study. MLX formed 1:1 M stoichiometric binary and ternary inclusion complexes as demonstrated by the AL-type of phase solubility curve. An increment in the stability constant value (Kc) of MLX- HPβCD complex in the presence of ethanolamines conceded higher complexation efficiency. Solid state analysis (FTIR, TGA, and SEM studies) of ternary compounds evidenced the perfect inclusion complex formation. Ternary complexes showed significant improvement in drug dissolution compared topure MLX and MLX-HPβCD binary complex. The ternary complex containing 1:1:1 molar ratio of MLX-HPβCD-DEA exhibited 86.91% drug dissolution in 1 hour, which was significantly high in relation to ternary complexes containing mono and tri ethanolamines, and it was found to follow imperatively matrix order release mechanism. On aging studied complexes showed no significant change in physical appearance, drug content and drug dissolution attributes, which clearly shows high in-vitro stability of the complexes.


Author(s):  
SAKSHI KAUSHIK ◽  
RAVINDER VERMA ◽  
DEEPIKA PUROHIT ◽  
PARIJAT PANDEY ◽  
MANISH KUMAR ◽  
...  

Objective: The current research objective is systematic development and characterization of binary and ternary inclusion complexes of cefuroxime axetil with β-cyclodextrin to improve its pharmaceutical characteristics by using the kneading method. Methods: Phase solubility study was carried out using Higuchi and Connors method. Based on its result, binary complexes of cefuroxime axetil with different ratio of β-cyclodextrin were developed and characterized using differential scanning calorimeter (DSC), fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffractometry (XRD). Then, binary complexes were analyzed for in vitro dissolution testing. The ternary complexes were developed using different ratio of PVP K-30 as a ternary component and evaluated for in vitro dissolution testing and in vitro taste masking. Results: Binary complex of cefuroxime axetil with β-cyclodextrin (1:1) showed better drug release than pure drug. During the development of the ternary complex, β-cyclodextrin (1:1) and 1% w/v PVP K-30 as a ternary agent resulted in an optimized ternary complex. The DSC, FT-IR and XRD studies clearly revealed the formation of binary and ternary complexes. The ternary complex showed better drug release of>85% within 30 min. in comparison to binary complex. The in vitro taste-masking study revealed the taste masking efficiency of the ternary complex of cefuroxime with β-cyclodextrin. Conclusion: The developed binary and ternary complex of cefuroxime axetil based on β-cyclodextrin with PVP K-30 showed improved in vitro dissolution rate and taste masking in comparison to pure drug. The drug release was better in ternary complexes. The present research work successfully shows the utility of binary and ternary complexes for improving pharmaceutical characteristics of cefuroxime axetil.


Archaea ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-14
Author(s):  
Ekaterina Yu. Bezsudnova ◽  
Tatiana E. Petrova ◽  
Natalia V. Artemova ◽  
Konstantin M. Boyko ◽  
Ivan G. Shabalin ◽  
...  

We present the functional and structural characterization of the first archaeal thermostable NADP-dependent aldehyde dehydrogenase AlDHPyr1147. In vitro, AlDHPyr1147 catalyzes the irreversible oxidation of short aliphatic aldehydes at 60–85°С, and the affinity of AlDHPyr1147 to the NADP+ at 60°С is comparable to that for mesophilic analogues at 25°С. We determined the structures of the apo form of AlDHPyr1147 (3.04 Å resolution), three binary complexes with the coenzyme (1.90, 2.06, and 2.19 Å), and the ternary complex with the coenzyme and isobutyraldehyde as a substrate (2.66 Å). The nicotinamide moiety of the coenzyme is disordered in two binary complexes, while it is ordered in the ternary complex, as well as in the binary complex obtained after additional soaking with the substrate. AlDHPyr1147 structures demonstrate the strengthening of the dimeric contact (as compared with the analogues) and the concerted conformational flexibility of catalytic Cys287 and Glu253, as well as Leu254 and the nicotinamide moiety of the coenzyme. A comparison of the active sites of AlDHPyr1147 and dehydrogenases characterized earlier suggests that proton relay systems, which were previously proposed for dehydrogenases of this family, are blocked in AlDHPyr1147, and the proton release in the latter can occur through the substrate channel.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Naciye Türkel

Nickel is one of the essential trace elements found in biological systems. It is mostly found in nickel-based enzymes as an essential cofactor. It forms coordination complexes with amino acids within enzymes. Nickel is also present in nucleic acids, though its function in DNA or RNA is still not clearly understood. In this study, complex formation tendencies of Ni(II) with adenine and certain L-amino acids such as aspartic acid, glutamic acid, asparagine, leucine, phenylalanine, and tryptophan were investigated in an aqueous medium. Potentiometric equilibrium measurements showed that both binary and ternary complexes of Ni(II) form with adenine and the above-mentioned L-amino acids. Ternary complexes of Ni(II)-adenine-L-amino acids are formed by stepwise mechanisms. Relative stabilities of the ternary complexes are compared with those of the corresponding binary complexes in terms ofΔlog10⁡K,log10⁡X, and % RS values. It was shown that the most stable ternary complex is Ni(II):Ade:L-Asn while the weakest one is Ni(II):Ade:L-Phe in aqueous solution used in this research. In addition, results of this research clearly show that various binary and ternary type Ni(II) complexes are formed in different concentrations as a function of pH in aqueous solution.


2021 ◽  
Vol 8 ◽  
Author(s):  
Jongseo Park ◽  
Hyung-Seop Youn ◽  
Jun Yop An ◽  
Youngjin Lee ◽  
Soo Hyun Eom ◽  
...  

DNA polymerase plays a critical role in passing the genetic information of any living organism to its offspring. DNA polymerase from enterobacteria phage RB69 (RB69pol) has both polymerization and exonuclease activities and has been extensively studied as a model system for B-family DNA polymerases. Many binary and ternary complex structures of RB69pol are known, and they all contain a single polymerase-primer/template (P/T) DNA complex. Here, we report a crystal structure of the exonuclease-deficient RB69pol with the P/T duplex in a dimeric form at a resolution of 2.2 Å. The structure includes one new closed ternary complex with a single divalent metal ion bound and one new open binary complex in the pre-insertion state with a vacant dNTP-binding pocket. These complexes suggest that initial binding of the correct dNTP in the open state is much weaker than expected and that initial binding of the second divalent metal ion in the closed state is also much weaker than measured. Additional conformational changes are required to convert these complexes to high-affinity states. Thus, the measured affinities for the correct incoming dNTP and divalent metal ions are average values from many conformationally distinctive states. Our structure provides new insights into the order of the complex assembly involving two divalent metal ions. The biological relevance of specific interactions observed between one RB69pol and the P/T duplex bound to the second RB69pol observed within this dimeric complex is discussed.


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