Simultaneous Nonchiral Determination of Artemisinin and Arteannuin B in Artemisia annua Using Circular Dichroism Detection

Artemisinin: a novel chiral electrochemiluminescence luminophore-assisted enantiospecific recognition and mechanism identification

Exploring novel electrochemiluminescence (ECL) molecules with high efficiency and good stability in aqueous solutions is crucial for achieving highly sensitive detection of analytes. However, developing chiral luminophores with efficient ECL performance is still a challenge. Herein, we first uncover that artemisinin (ART), a well-known chiral antimalarial drug, features a strong ECL emission at 726 nm with the assistance of a co-reactant potassium persulfate (K2S2O8), and an ECL efficiency of 195.3%, compared to that of standard Ru(bpy)3Cl2/K2S2O8. Mechanistic studies indicate that the strong ECL signal of ART is generated when the excited state formed by the reduction of ART peroxide bonds and combination with persulfate returns to the ground state. Significantly, we found that the ECL sensor based on chiral ART could efficiently identify and detect chiral cysteine (Cys) through ECL signals, with a lower limit of detection of 3.7 nM for l-Cys. Density functional theory calculations and scanning electrochemical microscopy technology further confirm that the disparity in the ECL signals is attributed to the different affinity between chiral ART and d/l-Cys, resulting in distinct electron transfer rates. The study demonstrates a new role of ART in ECL investigation and for the first time, achieves the development of ART for the enantioselective recognition and sensitive detection of chiral substances. This will be of vital significance for ECL and chirality research.

Recent Perspectives in Hot Melt Extrusion-Based Polymeric Formulations for Drug Delivery: Applications and Innovations

Hot melt extrusion (HME), a technology which mixing the advantages of solid dispersion technology and mechanical preparation, is accepted in varied applications in pharmaceutical formulations. When combined with other techniques, such as nanotechnique, three-dimensional printing, and co-extrusion, HME becomes much more multifunctional in the application of drug delivery. While in most cases, polymers employed in HME are responsible for the final property of products. The process of HME together with the selection of materials employed in HME were described briefly. In addition, the applications of HME in drug delivery and its currently status in the pharmaceutical field were also included. Some commercial products produced by HME have met the approval of FDA, indicating the commercial viability of this technique. Although showing great potential in pharmaceutical manufacturing, HME is still challenged by high temperature, shear force, and high input energy. Development of equipment, modifying the parameters, and optimization of polymeric formulations are needed for a safe, effective, and multifunctional hot melt extrusion drug delivery system. Also, wider range of combinations between HME and other techniques may provide guideline for developing multiple applications in drug delivery.

Application of hot melt extrusion for improving bioavailability of artemisinin a thermolabile drug

Hot melt extrusion has been used to produce a solid dispersion of the thermolabile drug artemisinin. Formulation and process conditions were optimized prior to evaluation of dissolution and biopharmaceutical performance. Soluplus^®, a low T_g amphiphilic polymer especially designed for solid dispersions enabled melt extrusion at 110 °C although some drug-polymer incompatibility was observed. Addition of 5% citric acid as a pH modifier was found to suppress the degradation. The area under plasma concentration time curve (AUC_0-24h) and peak plasma concentration (C_max) were four times higher for the modified solid dispersion compared to that of pure artemisinin.