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Searching for environmentally friendly aqueous two-phase systems is imperative for the sustainable development of separation technologies. In this work, five kinds of environmentally benign choline derivative ionic liquids were synthesized and used for the formation of aqueous two-phase systems with K 3 PO 4 , K 3 C 6 H 5 O 7 or K 2 CO 3 . In order to understand the phase formation processes of these aqueous two-phase systems and their possible application in extraction, phase diagrams and partition coefficients of purine alkaloids were determined at T  = 298.2 K, and the effects of structure of the ionic liquids, nature of the purine alkaloids, composition and temperature of the systems on the partitioning behaviour of purine alkaloids were investigated systematically. It was shown that caffeine, theobromine and 2,6-amino purine could be extracted effectively into the ionic liquid-rich phase of the aqueous two-phase systems, and the partition coefficients were as high as 4.5–42 under the optimized conditions. The partitioning was found to decrease with the increase of the ratio of H 2 O weight fraction (in the ionic liquid-rich phase and in the salt-rich phase) and hydrophobicity of both the purine alkaloids and the ionic liquids, but not sensitive to the change of temperature. [ABSTRACT FROM AUTHOR]

It is urgent to develop new antimalarial drugs with good therapeutic effects to address the emergence of drug resistance. Here, the artelinic acid-choline derivative (AD) was synthesized by dehydration reaction and esterification reaction, aimed to avoid the emergence of drug resistance by synergistic effect of artemisinins and choline derivative, which could compete with choline for rate-limiting enzymes in the phosphatidylcholine (PC) biosynthetic pathway. AD was formulated into liposomes (ADLs) by the thin-film hydration method. Efficacy of ADLs was evaluated by Peters 4-day suppression test. The suppression percentage against Plasmodium yoelii BY265 (PyBY265) in ADLs group was higher than those of positive control groups (dihydroartemisinin liposomes, P < 0.05) and other control groups (P ⩽ 0.05) at the doses of 4.4, 8.8, 17.6 µmol (kg·d)-1, respectively. The negative conversion fraction, recrudescence fraction and survival fraction of ADLs group were superior to other control groups. Pharmacokinetics in rats after intravenous injection suggested that ADLs exhibited higher exposure levels (indexed by area under concentration-time curve) than that of AD solution, artelinic acid liposomes or artelinic acid solution (P < 0.01). Taken together, ADLs exhibited promising antimalarial efficacy and pharmacokinetic characteristics.