In vitro and in vivo delivery of artemisinin loaded PCL-PEG-PCL micelles and its pharmacokinetic study

Artemisinin (ART) is a natural anti-malarial sesquiterpene lactone with anticancer properties, but its application is limited because of its low water solubility. To increase the bioavailability and water solubility of ART, we synthesized three series of poly (-caprolactone)-poly (ethylene glycol)-poly (-caprolactone) (PCL-PEG-PCL) tri-block copolymers. The structure of the copolymers was characterized by HNMR, FTIR, DSC and GPC techniques. ART was encapsulated inside micelles by a nanoprecipitation method which leading to the formation of ART/PCL-PEG-PCL micelles. The obtained micelles were characterized by DLS and AFM technique. The results showed that the average size of micelles was about 83.22nm. ART was encapsulated into PCL-PEG-PCL micelles with encapsulation efficacy of 89.23 +/- 1.41%. In vivo results demonstrated that this formulation significantly increased drug accumulation in tumours. Pharmacokinetic study in rats revealed that in vivo drug exposure of ART was significantly increased and prolonged by intravenously administering ART-loaded micelles when compared with the same dose of free ART. The MTT assay showed that bare PCL-PEG-PCL micelles is non-toxic to MCF7 and 4T1 cancer cell lines whereas the ART/PCL-PEG-PCL micelles showed a specific toxicity to both cancer cell lines. Therefore, the polymeric micellar formulation of ART based copolymer could provide a desirable process for ART delivery.