“…As shown in Fig.3a and 3b drug quenched the serum albumins fluorescence intensity then increased almost proportionally with the increase of CDs concentration added in the SA-Drug system. Studies of binding site with warfarin and ibuprofen by fluorescence spectroscopy reported in our previous article [41].Fig. 3Fluorescence spectra represent the (a) CDs-CPZ and (b) CDs- AMT system in the presence of different serum albumins; (c) Stern-Volmer plots of fluorescence quenching of HSA by drugs (λ max = 280 nm) (d) Plots of log(F0−F)/F vs. log [Q] for binding constant of HSA λ max = 280 nm at room temperature (pH 7.6).…”
Section: Resultsmentioning
confidence: 99%
“…The CDs was synthesized by one-pot method [41]. In a beaker 1.0 g glucose and 15 ml PEG-200 was added, and dissolve it in 30 ml Millipore water followed by stirring for 10 minutes, till a clear solution was obtained.…”
Section: Methodsmentioning
confidence: 99%
“…Generally, the binding nature of drug-albumins is dynamic and reversible [37, 38, 39, 40]. We have already reported in previous paper [41, 42, 43] the interaction of serum albumins with fluorescent carbon quantum dots, surfactants and antidepressant drugs by surface tensiometer, conductivity meter and spectroscopic techniques. Herein, the present investigation focused on the interaction of serum albumins (Scheme 1) with antidepressant drugs (Scheme 2) in absence and presence of carbon quantum dots (CDs).…”
A highly sensitive fluorescent carbon quantum dots (CDs) was designed to measure the interaction of antidepressant drugs and serum albumins (SA). In present investigation the interaction of bovine serum albumin (BSA) and human serum albumin (HSA) with antidepressant drugs viz. amitryptiline hydrochloride (AMT), chlorpromazine hydrochloride (CPZ) and desipramine hydrochloride (DSP) bioconjugated on CDs have been studied by different spectroscopic techniques i.e., Fluorescence, UV-Visible, Dynamic light scattering (DLS) and FT-IR. The CDs were prepared by one-pot method using glucose and PEG-200. The developed CDs showed blue luminescence under irradiation with ultra-violet. The Stern-Volmer quenching constant (K
sv
) indicates the presence of static quenching mechanism. The apparent binding constant
K
a
between antidepressant drugs with complex of SA-CDs have been determined. These results illustrated that CPZ shows strong binding with HSA. As further analyzed by FT-IR spectroscopy and DLS technique, the results suggested induced conformational changes on SA, thus confirming the experimental and theoretical results. Thus, a thorough knowledge of the energetics of drug-protein affinities in presence of CDs as attempted in this work is vital in giving way for appropriate drug delivery.
“…As shown in Fig.3a and 3b drug quenched the serum albumins fluorescence intensity then increased almost proportionally with the increase of CDs concentration added in the SA-Drug system. Studies of binding site with warfarin and ibuprofen by fluorescence spectroscopy reported in our previous article [41].Fig. 3Fluorescence spectra represent the (a) CDs-CPZ and (b) CDs- AMT system in the presence of different serum albumins; (c) Stern-Volmer plots of fluorescence quenching of HSA by drugs (λ max = 280 nm) (d) Plots of log(F0−F)/F vs. log [Q] for binding constant of HSA λ max = 280 nm at room temperature (pH 7.6).…”
Section: Resultsmentioning
confidence: 99%
“…The CDs was synthesized by one-pot method [41]. In a beaker 1.0 g glucose and 15 ml PEG-200 was added, and dissolve it in 30 ml Millipore water followed by stirring for 10 minutes, till a clear solution was obtained.…”
Section: Methodsmentioning
confidence: 99%
“…Generally, the binding nature of drug-albumins is dynamic and reversible [37, 38, 39, 40]. We have already reported in previous paper [41, 42, 43] the interaction of serum albumins with fluorescent carbon quantum dots, surfactants and antidepressant drugs by surface tensiometer, conductivity meter and spectroscopic techniques. Herein, the present investigation focused on the interaction of serum albumins (Scheme 1) with antidepressant drugs (Scheme 2) in absence and presence of carbon quantum dots (CDs).…”
A highly sensitive fluorescent carbon quantum dots (CDs) was designed to measure the interaction of antidepressant drugs and serum albumins (SA). In present investigation the interaction of bovine serum albumin (BSA) and human serum albumin (HSA) with antidepressant drugs viz. amitryptiline hydrochloride (AMT), chlorpromazine hydrochloride (CPZ) and desipramine hydrochloride (DSP) bioconjugated on CDs have been studied by different spectroscopic techniques i.e., Fluorescence, UV-Visible, Dynamic light scattering (DLS) and FT-IR. The CDs were prepared by one-pot method using glucose and PEG-200. The developed CDs showed blue luminescence under irradiation with ultra-violet. The Stern-Volmer quenching constant (K
sv
) indicates the presence of static quenching mechanism. The apparent binding constant
K
a
between antidepressant drugs with complex of SA-CDs have been determined. These results illustrated that CPZ shows strong binding with HSA. As further analyzed by FT-IR spectroscopy and DLS technique, the results suggested induced conformational changes on SA, thus confirming the experimental and theoretical results. Thus, a thorough knowledge of the energetics of drug-protein affinities in presence of CDs as attempted in this work is vital in giving way for appropriate drug delivery.
“…However, quenching constant K SV from pepsin−NFX or pepsin−OFX systems decreased with increased temperature (Table ), this indicated that fluorescence quenching of pepsin by FQS appeared to be due to static quenching. K q could be calculated using the above Equation ( τ 0 is 10 −8 s; Table ). According to published literature, the maximum collision quenching constant K q value from different quenchers with the biopolymer was about 2.0 × 10 10 L·mol −1 ·s −1 for dynamic quenching, but here actual values were much high than 2.0 × 10 10 L·mol −1 ·s −1 (Table ).…”
In this paper, the interactions of pepsin with fluoroquinolones, including norfloxacin (NFX) or ofloxacin (OFX), were investigated using fluorescence spectroscopy. The effects of NFX or OFX on pepsin showed that the molecular conformation of pepsin and the microenvironment of tryptophan residues were changed under mimicked physiological conditions. Static quenching was suggested as a factor. Quenching constants and binding constants were determined and thermodynamic parameters were calculated at three temperatures (25°C, 31°C and 37°C). Molecular interaction distances (binding distance r) were obtained. Binding was enthalpy driven and the process was spontaneous. Synchronous fluorescence, three-dimensional fluorescence spectroscopy and molecular simulation were used for analysis. Interactions were further tested using molecular modelling. Quenching and binding constants of NFX with pepsin were the highest when testing NFX/OFX/fleroxacin/gatifloxacin with pepsin combinations. NFX was the strongest quencher, and affinity of NFX for pepsin was higher than that of OFX/fleroxacin/gatifloxacin.
“…BSA system. In the assumption that BSA has independent binding sites for LSE BSA quenching process, the binding constant ( ) and binding sites in number ( ) are determined from the following equation [11];…”
A carrier protein called bovine serum albumin (BSA) interaction with proton-pump inhibitor such as lansoprazole (LSE) has been investigated at 295, 303 and 311 K in pH 7.40 by docking and [UV–vis, CD, FT–IR and fluorescence (emission, 3D and synchronous)]
spectroscopic studies. Emission fluorescence has suggested LSE BSA complex formation by static quenching with strong binding. This interaction has proceeded by Vander Waals and hydrogen bonding. An observation from competitive site marker and docking
experiments has resulted in binding of LSE with BSA transpired at site II, whereas from Förster’s theory a binding distance ( ) was retrieved to be 0.19 Å from LSE to Trp of BSA. Change in conformation, secondary structure and microenvironment of BSA were
noticed after LSE interaction. Diminished binding constant in Zn2+, Na+, Fe2+, Ca2+ and Co2+ ions presence on LSE-BSA interaction was also identified.
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