Spectrofluorimetric determination of the antineoplastic agent lomustine based on the sensitizing effect of β‐cyclodextrin

Abstract

The effects of solvent dipolarity/polarizability and solvent-solute hydrogen bonding on the photophysical properties of the antineoplastic drug lomustine were analysed by means of the linear solvation energy relationship (LSER) concept proposed by Kamlet and Taft. The LSER method enabled the overall solvent effects to be quantitatively estimated and separated into specific and non-specific contributions. The molecular encapsulation of lomustine by β-cyclodextrin (β-CD) has been studied using fluorescence spectroscopy. The results are discussed in terms of the binding parameter and the effect of the solvent used. It was concluded that β-CD forms a 1:1 inclusional complex with lomustine in acetonitrile solution and its association constant was calculated to be 500 M(-1). In addition, and for the first time, a simple, rapid and high sensitive fluorimetric method for the determination of lomustine was developed based upon the enhancement effect produced through complex formation with β-CD. The new approach for the quantification of lomustine in the presence of β-CD was described in aqueous and organic solutions. Better limits of detection (0.31 µg ml(-1)) and quantification (1.05 µg ml(-1)) were obtained in aqueous solution with respect to those obtained in organic solvent.

Mechanism and optimization of supramolecular complexation‐enhanced fluorescence spectroscopy for the determination of SN‐38 in plasma and cells

“…[ 41 ] Conversely, the excited guest molecules were protected from contacting water‐soluble quenchers such as molecular oxygen. [ 42 ] The fluorescence behaviours of SN‐38 and CD were closely related to solvent and pH, and intramolecular hydrogen bonds also play a vital role. In particular, it was affected by intermolecular hydrogen bonds formed by protic solvents such as water.…”

Synthesis and characterization of inclusion complex of -cyclodextrin and triazole picrate

“…Using the reciprocal plot from Figure 4 we have determined the apparent formation constant. The constant stability (k) for the host-guest inclusion complex was calculated and proved to be equal to 1.2.10 4 (mol/L) at 25 o C. The higher value of the formation constant of β -CD/picrate inclusion complex suggests that β-CD forms stable inclusion complex with picrate molecule and reveals the presence of strong interactions between the host and the guest [27].…”