Sweet Theophylline Cocrystal with Two Tautomers of Acesulfame

A novel pharmaceutical cocrystal (THPAH12) of Theophylline (THP) was obtained with an artificial sweetener, Acesulfame (AH), in a molar ratio of 1:2. Solid state NMR spectra of the cocrystal indicate that the two AH molecules exist as keto and enol tautomers, which is further confirmed by the refined crystal structure. THPAH12 is the first keto form AH containing cocrystal. This highlights the fact that not only −OH of enol form of AH, but also the −NH–CO group of the keto form of AH should be considered when designing new pharmaceutical cocrystals via the supramolecular synthon approach. Compared with pure THP, THPAH12 possesses enhanced solubility and hydration stability, which highlight its potential for further pharmaceutical applications

Graphene Oxide Based Theranostic Platform for <i>T</i>₁‑Weighted Magnetic Resonance Imaging and Drug Delivery

Magnetic resonance imaging (MRI) is a powerful and widely used clinical technique in cancer diagnosis. MRI contrast agents (CAs) are often used to improve the quality of MRI-based diagnosis. In this work, we developed a positive <i>T</i>₁ MRI CA based on graphene oxide (GO)–gadolinium (Gd) complexes. In our strategy, diethylenetriaminepentaacetic acid (DTPA) is chemically conjugated to GO, followed by Gd­(III) complexation, to form a <i>T</i>₁ MRI CA (GO–DTPA–Gd). We have demonstrated that the GO–DTPA–Gd system significantly improves MRI <i>T</i>₁ relaxivity and leads to a better cellular MRI contrast effect than Magnevist, a commercially used CA. Next, an anticancer drug, doxorubicin (DOX), was loaded on the surface of GO sheets via physisorption. Thus-prepared GO–DTPA–Gd/DOX shows significant cytotoxicity to the cancer cells (HepG2). This work provides a novel strategy to build a GO-based theranostic nanoplatform with <i>T</i>₁-weighted MRI, fluorescence imaging, and drug delivery functionalities