Electrochemical DNA Biosensor for Mycobacterium leprae Identification

Abstract Nowadays, a prompt and reliable diagnosis is one of the most critical measures for leprosy control. The current diagnostic is based on clinical exams by a health care professional, and it may not recognize early signs of the disease. Therefore, other leprosy diagnosis methods are needed that are sensitive, disease-specific, and easy to deliver to the end-user. This study describes the construction of an electrochemical DNA biosensor to detect PCR products of Mycobacterium leprae using methylene blue as an indicator of the hybridization. The capture probe was immobilized on the graphite electrode modified with poly(4-aminophenol). The electrode surface was morphologically characterized by atomic force microscopy. Linear voltammetry was used to monitor the concentration of methylene blue on the DNA biosensor, which indicated a limit detection of 1 x 10-10 mol/L. The biosensor showed selective when placed to hybridize with a non-complementary sequence. This study suggests that the electrochemical DNA biosensor developed is promising for detecting DNA of Mycobacterium leprae.

Recycling of expired paracetamol-containing drugs as source of useful reagents for an organic synthesis

All types of pharmaceutical waste negatively impact on the environment and human health and require specialmethods of utilization. In the current study, it is described that the elaboration of utilization methods of one of the mostcommonly used medicines as paracetamol of various brands and forms on the example of expired and substandarddrugs based on acid hydrolysis providing 4-aminophenol with 16%–87% yields. The actuality of obtaining the4-aminophenol derivatives revealed by their findings in the structure of many biologically active compounds withanticancer, antimicrobial, antioxidant, and cardiovascular activities. In addition, it has been demonstrated that thechemical transformation of paracetamol in capsule and tablet dosage forms providing N-[4-(benzyloxy)phenyl]acetamide as a useful reagent in an organic synthesis in the reaction with benzyl chloride in an alkaline medium. Thestructures of obtained products and purity were established on the basis of mass spectrometry (LCMS+) techniques.As a result, the simple procedure from moderate to good yield is an important feature of paracetamol-containing drugutilization as a source of different useful reagents for an organic synthesis and industrial production.

Determination of Aniline,2-Aminophenol and 4-Aminophenol in Mesalazine Sustained Release Granules by Gas Chromatography / 医药导报

Objective To establish a gas chromatography ( GC) method for determination of aniline,2-aminophenol and 4-aminophenol in mesalamine sustained release granules. Methods An HP-5 (10 m×0.53 mm,2.65 μm) capillary GC column was adopted. The carrier gas was high purity nitrogen at a flow rate of 15 mL.min-1 . The inlet temperature was controlled at 280 ℃ and the FID detector temperature was 300℃. The oven temperature was initially held at 70℃ for 2 min and was then programmed to 150 ℃ at 10℃.min-1 and held for 6 min. Results A good resolution was obtained between the peaks of the 3 impurities at chromatographic conditions above. The recoveries of aniline, 2-aminophenol and 4-aminophenol were among 98.04% to 103.00%. The precision and linearity equations were good. Conclusion The method can be adopted for the quality control of mesalazine sustained release granules.

A Biosensor Using Poly(4-Aminophenol)/acetylcholinesterase modified graphite electrode for the detection of dichlorvos

The properties of poly(4-aminophenol) modified graphite electrode as material for the immobilization of acetylcholinesterase were investigated by the Cyclic Voltammetry, Electrochemical Impedance Spectroscopy and Atomic Force Microscopy. The polymer was deposited on graphite electrode surface by the oxidation of 4-aminophenol and then acetylcholinesterase was immobilized on the surface of the electrode. The biosensor coupled in the continuous flow system was employed for the detection of dichlorvos. The detection and quantification limits were 0.8 and 2.4 μmol L-1 dichlorvos, respectively. Graphite electrodes modified with the poly(4-aminophenol) showed to be an efficient and promising material for immobilization of acetylcholinesterase enzyme. The proposed method requires simple parts which are easy to build, involves only one biosensor and the potentiometric detection is simple.