01 to 200μM [42]. Significant cytotoxicity was found only by using folate-conjugated lipoZOL, especially in cell overexpressing the folate receptor. The discrepancy among the two studies could be ascribed to the different

formulations used as well as to the different cell lines. The in vivo antitumor activity of lipoZOL was demonstrated in two different model of tumors, namely, prostate cancer and multiple myeloma [40, 41]. In these experiments, mice treated with lipoZOL, compared to animal with free ZOL, showed a higher tumor weight BMS-345541 purchase inhibition and tumor growth delay, together with increased mice survival. As in the Inhibitors,research,lifescience,medical case of non-stealth nanocarriers, also stealth liposomes allowed to obtain reduced number of TAM as well as inhibition of the neoangiogenesis [40, 41]. Moreover, no significant changes were found in serum creatinine, urea, and calcium in animals treated with lipoZOL, suggesting the absence Inhibitors,research,lifescience,medical of potential adverse effects [40]. In order to overcome technological limits of the lipoZOL, such as low encapsulation efficiency and stability issue of the liposomal Inhibitors,research,lifescience,medical formulation, our group recently developed a new nanovector

to deliver ZOL in extraskeletal tumor. The new system consists of self-assembling NPs encapsulating ZOL and designed to be prepared before use, thus avoiding storage issues [43, 102]. In particular, the formulation can be prepared by mixing two components, namely, an aqueous solution of ZOL, Ca2+/PO43− NPs, and cationic PEGylated liposomes. Ca2+/PO43− have already been used to deliver other negatively charged molecules, such as nucleic acids [103]. In the case of BPs, an encapsulation process driven by ionic interactions allowed to overcome the loading Inhibitors,research,lifescience,medical issues observed with Inhibitors,research,lifescience,medical liposomes. Indeed, in the case of self-assembling NPs, a ZOL encapsulation efficiency 12-fold greater, compared with that obtained with ZOL-containing liposomes,

was achieved. The self-assembling NPs increased the growth inhibition of ZOL on different cancer cell lines, compared to free ZOL. The highest cell growth inhibition was observed on breast cancer cells. The anticancer activity of this formulation was also demonstrated in vivo in an animal model of prostate cancer. ZOL encapsulated into self-assembling NPs elicited a marked antitumor activity, while free ZOL did not show a significant reduction because of tumor growth [43]. The in vivo anticancer activities of two different ZOL-containing nanocarriers, namely, lipoZOL and self-assembling NPs, were compared [41]. In this study, self-assembling NPs encapsulating ZOL induced the complete remission of tumour xenografts and an increase of survival time higher than that observed with lipoZOL. This effect was paralleled by a significant increase of both necrotic and apoptotic indexes.