Slow release rate optimal for pegylated liposomal doxorubicin.

2004 AUG 5 - (NewsRx.com & NewsRx.net) -- Slow release rates produce optimal results with pegylated liposomal doxorubicin.

In a recent study from Canada, the "pharmacokinetics (PK), biodistribution (BD), and therapeutic activity of pegylated liposomal doxorubicin formulations with different drug release rates" were determined "in an orthotopic 4T1 murine mammary carcinoma model."

"The focus of these experiments was to study the effects of different release rates on the accumulation of liposomal lipid and doxorubicin (DXR) into the tumor and cutaneous tissues of mice (skin and paws)," explained G.J.R. Charrois and coauthors at the University of Alberta. "These tissues were chosen because the clinical formulation of pegylated liposomal doxorubicin (Caelyx/Doxil) causes mucocutaneous reactions such as palmar-plantar erythrodysesthesia (PPE)."

"Liposomes with different doxorubicin (DXR) leakage rates were prepared by altering liposome fluidity through changing the fatty acyl chain length and/or degree of saturation of the phosphatidylcholine component of the liposome," the scientists noted. "Liposomes with fast, intermediate, and slow rates of drug release were studied."

"The plasma PK of the liposomal lipid was similar for all formulations, while the plasma PK of the DXR component was dependent on the liposome formulation," test results revealed. "Liposomal lipid accumulated to similar levels in tumor and cutaneous tissues for all three formulations tested, while the liposomes with the ...