Annonaceous acetogenins nanosuspensions stabilized by PCL-PEG block polymer: significantly improved antitumor efficacy

Annonaceous acetogenins (ACGs) have shown superior antitumor activity against a variety of cancer cell lines, but their clinical application has been limited by their poor solubility. In this study, ACGs-nanosuspensions (NSps) were successfully prepared by a precipitation ultrasonic method using monomethoxypoly (ethylene glycol)2000-poly (ε-caprolactone)2000 (mPEG2000-PCL2000) as a stabilizer. The resultant ACGs-NSps had a mean particle size of 123.2 nm, a zeta potential of -20.17 mV, and a high drug payload of 73.68%. ACGs-NSps were quite stable in various physiological solutions, and they exhibited sustained drug release. Compared to free drug, ACGs-NSps exhibited stronger cytotoxicity against 4T1, MCF-7, and HeLa cells. An in vivo real-time biodistribution investigation after labeling with 1,1'-dioctadecyltetramethyl indotricarbocyanine iodide, a noninvasive near-infrared fluorescence probe, demonstrated that ACGs-NSps could effectively accumulate in tumor. An in vivo antitumor activity study in 4T1 tumor-bearing mice revealed that ACGs-NSps achieved much better therapeutic efficacy than the traditional dosage form (oil solution) even at 1/10 of the dose (74.83% vs 45.53%, P<0.05), demonstrating that NSp was a good dosage form for ACGs to treat cancer.