Release and extraction of letrozole in blood plasma using resorcinol functionalized multi-walled carbon nanotube coupled with high-performance liquid chromatography

The study of Letrozole adsorption upon CCT nanotube: A DFT/TD-DFT and spectroscopic (excited states and UV/Vis)

In this research, the geometric structure of LTZ and CCT (5,0) was optimized with B3LYP/6-31G * method using the Gaussian 09W program package to investigate the weak interaction of Letrozole (LTZ) and carbon carbon nanotube (CCT). According to the calculation of the release energy, it was found that the drug delivery process is desirable. Also, the structural properties of the title compounds were assessed by thermodynamic and frontier molecular orbital (FMO) parameters. In this study, a series of measures have been performed to detect changes in drug loading properties and non-bonding interactions between the LTZ and CCT (5,0) nanotube. The non-bonding interaction effects of LTZ and CCT over the electronic properties were also evaluated and argued. The research is based on the fact that studies can help to understand the interaction between the LTZ drug and CCT (5,0) nanotube and the development of CCT-based drug release systems. This research aimed to determine variations in electronic properties of anticancer LTZ drug in presences CCT. Then, the reactivity and stability behavior of LTZ drug and on CCT to be examined by density functional theory (DFT). Then, frontier molecular orbital (FMO) and noncovalent interaction (NCI) analyses were performed, which decrease in reactivity described increase in the stability of LTZ drug.

Electrodeposition of poly-ethylenedioxythiophene-graphene oxide nanocomposite in a stainless steel tube for solid-phase microextraction of letrozole in plasma samples

Coated stainless steel was used as an in-tube solid-phase microextraction for the extraction of letrozole from plasma samples. The coating process on the inner surface of the stainless steel was conducted by a simple electrodeposition process. The coated composite was prepared from 3,4-ethylenedioxythiophene and graphene oxide. In this composite, graphene oxide acts as an anion dopant and sorbent. The coated nanostructured polymer was characterized using different techniques. The operational factors affecting the extraction process, including pH, adsorption, and desorption time, the recycling flow rate of the sample solution, sample volume, desorption solvent type and its volume, and ionic strength were optimized to achieve the best extraction efficiency of the analyte. The total extraction time including adsorption and desorption steps was about 15.0 min. The developed method demonstrated a linear range of 5.0-1500.0 μg/L with a limit of detection of 1.0 μg/L. The repeatability of the developed extraction approach in terms of intraday, interday, and fiber to fiber was attained in the range of 4.9-8.3%. After finding the optimal conditions, the potential of the described approach for letrozole quantitation was investigated in plasma samples, and satisfactory results were obtained.

Synthesis and characterization of new surface modified magnetic nanoparticles and application for the extraction of letrozole from human plasma and analysis with HPLC-fluorescence

Acetic acid-functionalized magnetic nanoparticles modified by (3-amino-propyl)-tri-ethoxy silane was synthesized and used as a new solid-phases adsorbent. Infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDX), vibrating sample magnetometer (VSM) and Electrophoretic Light Scattering (ELS) were used to characterize the modified nanoparticles. The molecular interaction between letrozole and nanoparticles (NPs) was studied using density functional theory (DFT) calculations. The developed nanoparticles were applied for dispersive solid-phase extraction of letrozole (an anticancer drug) from human plasma. Extracted letrozole was quantified using an isocratic HPLC/FL method. The extraction efficiency was optimized using one experiment at a time optimization method based on the adsorbent quantity, sample pH, adsorption time, desorption time, and elution solvent type/volume. The analysis method was fully validated according to the FDA guideline for bioanalytical method validation. The linear quantification range was 0.01-1 μg/mL and the lower limit of quantification (LLOQ) was 0.01 μg/mL. Plasma samples of 6 patients were analyzed and the measured letrozole concentrations range was 0.04-0.31 μg/mL. The newly synthesized magnetic nanoparticles were used successfully for the extraction of letrozole from spiked and clinical plasma samples. The developed method is a precise and simple method that is suitable for pharmacokinetic studies and clinical applications.