Voltammetric determination of 6-mercaptopurine using [Co(phen)3]3+/MWNT modified graphite electrode

A New Electrochemical Sensor for Direct Detection of Purine Antimetabolites and DNA Degradation

The development of a reliable electrochemical sensor using a hybrid nanocomposite consisting of ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) functionalized graphene oxide (GrO-IL) and gold nanoparticles (AuNPs) stabilized by chitosan (Chit) was described. The new sensor, labelled as GrO-IL-AuNPs-Chit/CSE, exhibited an improved electrocatalytic response to cancer drugs such as purine antimetabolites (6-thioguanine, 6-mercaptopurine, and azathioprine) in a wide concentration range with a low detection limit (20-40 nmol·L^-1, S/N = 3), and satisfactory recoveries (97.1-103.0%). The sensor has been also successfully used for cyclic voltammetric study of a salmon sperm double-stranded DNA degradation and DNA-6-mercaptopurine interaction in aqueous solutions (pH 7.4).

A new fluorescent nitrogen-doped carbon dot system modified by the fluorophore-labeled ssDNA for the analysis of 6-mercaptopurine and Hg (II)

A simple, environmentally friendly hydrothermal method was used to prepare strongly luminescent, nitrogen-doped carbon dots (NCDs) with the use of Chinese yams as a source of carbon and nitrogen. Such NCDs have an average size of 2.7±1.4 nm; they emit blue light at 420 nm and have a quantum yield of up to 9.3%. Thus, carboxyfluorescein (FAM)-DNA macro-molecules were assembled on the surfaces of the NCDs, and stabilised by strong π-π stacking; the so formed hybrid nano-sensors were found to have an ultra-sensitive response to 6-mercaptopurine (6-MP). A strong emission and enhancement of yellow radiation was observed from FAM. Furthermore, due to the specific interactions between DNA and Hg(2+), which resulted in the formation of the T-Hg(2+)-T (T: thymine base) complex - a large, conjugated system, which formed between NCDs, DNA and 6-MP, was broken up. Thus, the fluorescence from FAM was quenched. The detection limits for 6-MP and Hg(2+) were 0.67 and 1.26 nM, respectively. The proposed method was applied for the determination of 6-MP in human serum and Hg(2+) in water samples with satisfactory results.

Selective recognition of 6-mercaptopurine based on luminescent metal-organic frameworks Fe-MIL-88NH₂

A novel and rapid spectrofluorometry method for the recognition of 6-mercaptopurine (6-MP) has been developed based on luminescent metal-organic frameworks Fe-MIL-88NH2 as fluorescent probe. The strong fluorescence of Fe-MIL-88NH2 at 430 nm could be quenched by 6-MP directly, and the Fe-MIL-88NH2 shows high selectivity for 6-MP compared to other thiol-containing amino acids such as homocysteine (Hcy), cysteine (Cys), glutathione (GSH), etc. Under optimal conditions, the relative fluorescence intensity was linearly proportional to the concentration of 6-MP in the range of 5-600 μM with the detection limit at 1.17 μM (S/N=3). Furthermore, the present approach has been successfully applied to the determination of 6-MP in human serum samples. The possible fluorescence quenching mechanism has also been investigated, where it is revealed that the quenching was attributed to competition of absorption of the light source energy as well as electron transfer between Fe-MIL-88NH2 and 6-MP.

Spectrophotometric Determination of 6-Mercaptopurine in Pharmaceutical Sample Using Fe(III)-Potassium Ferricyanide System

In the present work,we developed a simple,fast,sensitive and inexpensive method to determine 6-mercaptopurine (6-MP) in pharmaceutical sample using Fe (III)-potassium ferricyanide system by spectrophotometry.The results show that in acid medium, Fe (Ш) can be reduced to Fe (II) by hydrosulfuryl (-SH) in 6-Mercaptopurin molecule, and then Fe (II) reacts with potassium ferricyanide to form a soluble Prussian blue (KFeIII[FeII(CN)6]),the content of 6-MP was determinated indirectly through determinating the absorbance of the soluble Prussian blue.The various effect factors on the determination of 6-MP by spectrophotometry using potassium Fe (III)-ferricyanide system were investigated in detail.The maximum absorption wavelength of chromogenic system was 755 nm, good linear relationship was obtained between the absorbance and the concentration of 6-MP in the range of 0.4120~2.884 μ g·/mL,the equation of the linear regression was A=0.0411+0.1462C (μ g·/mL),with a linear correlation coefficient was 0.9991.This proposed method had been successfully applied to determinate of 6-MP in real pharmaceutical,and the results agreed well with those obtained by pharmacopoeial method.

Decrease in cytotoxicity of copper-based intrauterine devices (IUD) pretreated with 6-mercaptopurine and pterin as biocompatible corrosion inhibitors

The copper intrauterine device (IUD) based its contraceptive action on the release of cupric ions from a copper wire. Immediately after the insertion, a burst release of copper ions occurs, which may be associated to a variety of side effects. 6-Mercaptopurine (6-MP) and pterin (PT) have been proposed as corrosion inhibitors to reduce this harmful release. Pretreatments with 1 × 10(-4) M 6-MP and 1 × 10(-4) M PT solutions with 1h and 3h immersion times were tested. Conventional electrochemical techniques, EDX and XPS analysis, and cytotoxicity assays with HeLa cell line were employed to investigate the corrosion behavior and biocompatibility of copper with and without treatments. Results showed that copper samples treated with PT and 6-MP solutions for 3 and 1 h, respectively, are more biocompatible than those without treatment. Besides, the treatment reduces the burst release effect of copper in simulated uterine solutions during the first week after the insertion. It was concluded that PT and 6-MP treatments are promising strategies able to reduce the side effects related to the "burst release" of copper-based IUD without altering the contraceptive action.

Determination of 6-mercaptopurine in the presence of uric acid using modified multiwall carbon nanotubes-TiO2 as a voltammetric sensor

In this work, a multiwall carbon nanotubes modified electrode (prepared by incorporating TiO(2) nanoparticles with p-aminophenol as a mediator) was used as voltammetric sensor for the determination of 6-mercaptopurine (6-MP) in the presence of uric acid (UA). The voltammograms of 6-MP and UA in a mixture can be separated from each other by differential pulse voltammetry with a potential difference of 380 mV at a scan rate of 10 mV s(-1). These conditions are sufficient to allow for the determination of 6-MP and UA both individually and simultaneously. The electrocatalytic currents increase linearly with 6-MP concentration in the ranges of 0.09-350 µmol L(-1) (two linear segments with different slopes). The detection limit for 6-MP was 0.065 µmol L(-1) . The RSD% for 1.0 and 15.0 µmol L(-1) 6-MP were 0.7%, and 1.2%, respectively. The kinetic parameters of the system were determined using electrochemical approaches. The method was successfully applied for the determination of 6-MP in drug sample, and 6-MP plus UA in urine samples.