Poly (aspartic acid-co-lactic acid) (PAL) has been investigated as a new biodegradable material for Drug Delivery Systems (DDS). Similar to the
poly (lactic acid-co-
glycolic acid) (PLGA)
nanospheres, the PAL
nanospheres can control-release encapsulated drugs by hydrolysis and adhere to the mucous membranes to improve the
drug absorption. In this study, the
vitamin encapsulated PAL
nanospheres were applied on mice to examine their effect on
tumor metastasis and safety as an
injectable DDS material for anti-
cancer and other drugs. In the experiment, 6 C57BL/6 mice per group were intravenously administered with B16BL6
melanoma cells (1 x 10(5) per mouse) and non-encapsulated PAL
nanospheres or pro-
vitamin encapsulated
nanospheres respectively, while the control group was administered with B16BL6 cells alone. Two weeks later, the lungs of the mice were excised and metastatic foci on the lung surface were counted. The
melanoma cell
metastasis to lungs was prevented by intravenous co-injection of B16BL6
melanoma cells with 1.7 microg of pro-
vitamin E encapsulated PAL
nanospheres. Its metastatic foci count (mean +/- SD) was 127+/-80, which was better than the control (246+/-95, p<0.02). Also, applying the pro-
vitamin C and pro-
vitamin A encapsulated PAL
nanospheres as well as the non-encapsulated PAL
nanospheres slightly decreased the number of
metastasis colonies in the lungs as compared to that of the control. These results suggested that PAL
nanospheres did not promote the lung
metastasis of B16BL6
melanoma cells. Thus, the PAL
nanospheres are safe material for injection applications.