Non-stealth and stealth solid lipid nanoparticles (SLN) carrying doxorubicin: pharmacokinetics and tissue distribution after i.v. administration to rats.

Non-stealth and stealth solid lipid nanoparticles (SLN) carrying doxorubicin were prepared as drug delivery systems. The pharmacokinetics and tissue distribution of doxorubicin in these SLN were studied after i.v. administration to conscious rats and were compared to the commercial solution of doxorubicin. The same dose of each formulation (6 mg kg(-1)of body weight) of doxorubicin was injected in the rat jugular vein. Blood samples were collected after 1, 15, 30, 45, 60 min and 2, 3, 6, 12, and 24 h after the injection. Rats were sacrificed after intervals of 30 min, 4 h, and 24 h and samples of liver, spleen, heart, lung, kidney, and brain were collected. In all samples, the concentration of doxorubicin and of the metabolite, doxorubicinol, were determined. Doxorubicin and doxorubicinol were still present in the blood 24 h after injection of stealth and non-stealth SLN, while they were not detectable after the injection of the commercial solution. The results confirmed the prolonged circulation time of the SLN compared to the doxorubicin solution. In all rat tissues, except the brain, the amount of doxorubicin was always lower after the injection of the two types of SLN than after the injection of the commercial solution. In particular, SLN significantly decreased the heart concentration of doxorubicin.