Cocrystal of Apixaban-Quercetin: Improving Solubility and Bioavailability of Drug Combination of Two Poorly Soluble Drugs.

Drug combinations have been the hotspot of the pharmaceutical industry, but the promising applications are limited by the unmet solubility and low bioavailability. In this work, novel cocrystals, consisting of two antithrombotic drugs with poor solubility and low bioavailability in vivo, namely, apixaban (Apx) and quercetin (Que), were developed to discover a potential method to improve the poor solubility and internal absorption of the drug combination. Compared with Apx, the dissolution behavior of Apx-Que (1:1) and Apx-Que-2ACN (1:1:2) was enhanced significantly, while the physical mixture of the chemicals failed to exhibit the advantages. The dissolution improvements of Apx-Que-2ACN could be explained by the fact that the solid dispersion-like structure and column-shaped cage of Que accelerated the access of the solvent to the inner layer of Apx. The fracture of the hydrogen bonds of Apx, which was the joint of the adjacent Que chains, facilitated the break-up of the structures. Besides, the bioavailability of Apx-Que was increased compared with the physical mixture and Apx, and Apx-Que remained stable in high temperature and illumination conditions. Therefore, a drug-drug cocrystal of two antithrombotic agents with poor solubility was developed, which exhibited greatly improved solubility, bioavailability and superior stability, indicating a novel method to overcome the shortages of drug combination.

A Novel Co-Crystal of Bexarotene and Ligustrazine Improves Pharmacokinetics and Tissue Distribution of Bexarotene in SD Rats.

Bexarotene (BEX), a specific retinoic acid X receptor (RXR) agonist granted by Food and Drug Administration (FDA) approval for the clinical treatment of T cell lymphoma, has now been found to exert pharmacological effects in the nervous system, with low bioavailability and poor cerebral distribution limiting its application in treatment on neurological disorders. Pharmaceutical co-crystal was a helpful method to improve the bioavailability and tissue distribution of active pharmaceutical ingredients (APIs). Here, 2bexarotene-ligustrazine (2BEX-LIG), a novel co-crystal system of BEX and ligustrazine (LIG) of which with BEX is an API, was constructed with satisfactory stability and enhanced solubility. The pharmacokinetics characteristics of BEX were detected, and the results showed that the absolute bioavailability and the cerebral concentration of BEX in rats administrated with 2BEX-LIG were enhanced from 22.89% to 42.86% and increased by 3.4-fold, respectively, compared with those in rats administrated an equivalent of BEX. Hence, our present study indicated that the novel co-crystal of 2BEX-LIG contributed to improving BEX oral bioavailability and cerebral distribution, thereby providing significant advantages for clinical application of brain tumors and other neurological diseases.

Solubility and Stability Advantages of a New Cocrystal of Berberine Chloride with Fumaric Acid.

BBC is a drug with a variety of activities but poor solubility. Cocrystal technology is an effective method to improve the solubility and stability of this type of compound. In this work, the cocrystal of BBC with fumaric acid was obtained at a stoichiometric ratio of 2:1. Studies on stabilities and solubilities were carried out using BBC dihydrate and tetrahydrate as reference materials. Results showed that this new cocrystal did not only significantly improve the dissolution rate of BBC but also highly improved the stability in high humidity and temperature. Given that the cocrystals formed by BBC as the host molecule were few, different techniques were applied for characterization and structural analyses. Moreover, theoretical calculations were performed on weak interactions, such as hydrogen bonding and π-π stacking interactions, which provided the research data for the study of this kind of cocrystal.

Development of a new chlorogenic acid certified reference material for food and drug analysis.

This paper reports the preparation and characterization of a new chlorogenic acid (CHA) certified reference material (CRM), which is unavailable commercially. CHA is an active ingredient found in many geo-authentic Chinese medicinal materials and developed as an anti-cancer drug. In this work, trace impurities were isolated and identified through various techniques. CHA CRM was quantified with two analytical methods, and their results were in good agreement with each other. The certified value and corresponding expanded uncertainty of CHA CRM reached 99.4%±0.2%, which was calculated by multiplying the combined standard uncertainty by the coverage factor (k=2), at a confidence level of 95%. This CRM can be used to calibrate measurement system, evaluate or validate measurement procedures, assign traceable property values to non-CRMs, and conduct quality control assays.