Evaluating Ternary Metal Oxide (TMO) core-shell nanocomposites for the rapid determination of the anti-neoplastic drug Chlorambucil (Leukeran™) by electrochemical approaches.

A functional ternary nanocomposite (MnO2@NiFe2O4) with hierarchically grown flower-like core-shell assembly has been prepared through a simple two-step hydrothermal methodology. The crystallographic information of the sample was obtained via X-ray diffraction. The morphological details of spherical NiFe2O4 (core) and flower-like MnO2 (shell) were examined over FE-SEM and TEM; finally, the XPS confirms the successful formation of MnO2@NiFe2O4 ternary nanocomposite. The surface area of finely grown hierarchical MnO2 flowers on NiFe2O4 nanoparticles was measured through BET isothermal studies. The ternary nanocomposite was employed for the specific and sensitive detection of anticancer drug Chlorambucil. Under the well-optimized condition, the graphically plotted calibration curve was attained at MnO2@NiFe2O4/GCE towards the detection of anticancer drug Chlorambucil, which possesses the wider linear range of 0.025-574.5 µM, with the minimal detection limit of 4.68 nM. The feasibility of the sensitive layer has also been inspected on the pharmaceutical sample (oral tablets) and the biological matrix (human urine), whereas the appreciable spike recoveries were obtained.

Glutathione conjugation of chlorambucil: measurement and modulation by plant polyphenols.

Chlorambucil (CMB), an anticancer drug, was cytotoxic at concentrations of 5-20 microM to human colon adenocarcinoma cells. It inhibited [14C]thymidine uptake in a dose-dependent manner. Both effects were potentiated by simultaneous exposure of the cells to 10 microM plant polyphenols. In an attempt to explain the possible mechanism of action of the polyphenols in relation to these observations, an HPLC-radiometric method was developed to measure the conjugation of CMB with glutathione in these cells and to monitor the export of monochloromonoglutathionyl CMB (MG-CMB), its main glutathione conjugate. At micromolar concentrations, five polyphenols, namely quercetin, butein, tannic acid, 2'-hydroxychalcone and morin, inhibited the efflux of CMB significantly; an inhibition of 40% was observed with 10 microM quercetin. The glutathione S-transferase (GST) activity of the cancer cells, measured with 1-chloro-2,4-dinitrobenzene, was also inhibited by the polyphenols. Their combined action on GST and on the efflux of MG-CMB conjugate could provide an enhanced positive modulation of sensitivity of the tumour cells to CMB.

Cellular kinetics of prednimustine versus chlorambucil plus prednisolone in vitro.

Intracellular concentrations of prednimustine (PM), chlorambucil (CLB), phenylacetic acid mustard (PAAM) and prednisolone (P) were measured in different experimental tumor cell lines that had been incubated with either PM or CLB + P. For intracellular analytical determination, we modified a high-pressure liquid chromatographic method for the detection of these substances in plasma. Intact PM could be detected in the intracellular compartment of the incubated tumor cells. PM-incubated cells from PM-injected rats exhibited a higher intracellular concentration-time integral (PAAM) and longer concentration-time profiles for drugs with alkylating capacity than did cells exposed to the CLB + P mixture or to CLB. PAAM was not detectable after incubation of cells with PM, whereas in CLB-incubated cells the AUC of PAAM exceeded that of the parent drug CLB. Our in vitro results therefore favour the concept of a facilitated intracellular uptake and an increased antiproliferative effect for PM versus CLB and CLB + P.

Characterization of glutathione conjugates of chlorambucil by fast atom bombardment and thermospray liquid chromatography/mass spectrometry.

Chlorambucil (p-(di-2-chloroethyl)amino-gamma-phenylbutyric acid) is a bifunctional alkylating agent which exhibits acquired drug resistance upon repeated dosing in humans. This compound reacts with glutathione both non-enzymatically and enzymatically in the presence of immobilized microsomal glutathione-S-transferases to produce several glutathione conjugates. These conjugates result from displacement of one or both chlorines by the nucleophilic cysteine sulfhydryl moiety of glutathione. The mono- and diglutathionyl conjugates of chlorambucil were purified by reversed-phase high-performance liquid chromatography and characterized by positive ion fast atom bombardment mass spectrometry. In addition, the mono- and dihydroxy hydrolysis products of chlorambucil were characterized by positive ion thermospray liquid chromatography/mass spectrometry (LC/MS). The glutathione conjugates of chlorambucil did not produce molecular ion species in thermospray LC/MS mode, but gave characteristic ions at m/z 147 corresponding to fragmentation of the glutathione moiety. The formation of glutathione conjugates of this class of alkylating agents may play a role in the development of acquired drug resistance.

Heptakis(2,6-di-O-methyl)-beta-cyclodextrin complexation with the antitumor agent chlorambucil.

The effects of heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DIMEB) and of beta-cyclodextrin (beta-CD) on the aqueous solubility and stability of chlorambucil (CHL) have been compared. In the presence of 1.3 x 10(-3) M DIMEB, there is a greater than 20-fold increase in the stability of chlorambucil at 37 degrees C, pH 4.13. Aqueous solubility of CHL is increased more than 40-fold in the presence of 1.74 x 10(-2) M DIMEB when the solubility is studied under conditions where degradation is minimized (3.0 degrees C, pH 4.13). In the presence of 1.3 x 10(-3) M beta-CD, there is a fourfold increase in the stability, and with 1.74 x 10(-2) M beta-CD, there is a threefold increase in the aqueous solubility of CHL under similar conditions. Stability constants of the CHL complex with DIMEB were determined kinetically and spectrophotometrically under various experimental conditions assuming 1:1 inclusion complex formation.