Apixaban
(apx), with a trade name of Eliquis, is a highly selective
and efficacious inhibitor of blood coagulation factor Xa. Apixaban
has poor solubility in water (0.028 mg/mL at 24 °C) and a relatively
low oral bioavailability (about 50% for a single 10 mg dose). The
purpose of this study is to improve the solubility and consequently
the oral bioavailability of apixaban via a cocrystal. A cocrystal
of apixaban with oxalic acid (apx-oxa-H2O, 4:3:0.5) was
successfully obtained and characterized. The structure of the cocrystal
was determined by single-crystal X-ray diffraction. The solubility
of the cocrystal in 0.1 M HCl (pH 1.0) and phosphate buffer of pH
6.8 was evaluated, and the results show the solubility values of the
cocrystal are approximately 2.2 and 2.1 times as large as those of
apixaban form N-1 (the marketed product), respectively. The pharmacokinetics
in beagle dogs was also investigated, and the mean AUC0–24h of the cocrystal is approximately 2.7 times as large as that of
apixaban form N-1, indicating that both solubility and bioavailability
of apixaban can be improved via a cocrystal.
A Fe‐porphyrin covalent organic framework (Fe‐PorCOF) was prepared through a postmodification strategy and characterized using different techniques. Fe‐PorCOF exhibits an inherent peroxidase/oxidase mimetic catalytic activity and sharply accelerates chemiluminescence (CL) reactions between luminol and hydrogen peroxide (H2O2) or dissolved oxygen (O2) under alkaline conditions. The catalytic role was attributed to a significant increase in production of reactive oxygen species. Using the imminent peroxidase mimetic catalytic activity of Fe‐PorCOF, a new CL method was developed for determination of H2O2 over a linear range from 0.01 to 10.0 μmol·L−1 and with a limit of detection of 5.3 nmol·L−1. The combination of the peroxidase mimetic catalytic activity of Fe‐PorCOF with the catalytic activity of glucose oxidase on glucose oxidation presents a sensitive CL method for glucose assay. The linear range and the detection limit for glucose were 0.05–8.0 μmol·L−1 and 4.0 nmol·L−1, respectively. The practicability of this method was assessed by determination of glucose in human sera. As a peroxidase/oxidase mimetic, Fe‐PorCOF is easy to prepare and exhibits good catalytic efficiency in the luminol reaction. We believe that this strategy will promote the development of a CL field with functional COFs as a catalyst.
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