Comparative investigation of antitumor activity of liposomal dosage forms of nitrosoalkylurea derivatives

Lysomustine is an original antitumor preparation, chloroethylic derivative of nitrosourea on L-homocitrulline basis. BCNU is 1,3-bis (2-chloroethyl)-1 -nitrosourea, Carmustine (BiCNU) generic substance. PEG- liposomes of Lysomustine and BCNU with PEG-5000 (LEF-5000) and PEG-2000 (LEF-2000) in lipid membranes have been obtained. The antitumor efficiency of new pharmaceutical formulations was investigated on experimental tumor model - lymphoblastic leucosis L-1210. Lysomustine in LEF-5000 on lymphoblastic leucosis L-1210 had shown optimal therapeutic effect at doses from 125 to 250 mg/kg resulting in 100 % recovery of treated animals, while LEF-2000 showed 100 % antitumor effect only at a dose of 175 mg/kg. BCNU in LEF5000 had shown maximal therapeutic effect at doses 40 and 45 mg/kg (100 % recover of animals) Dose of 50 mg/kg caused 100 % animals death due to toxicity. No 100 % recovery was revealed using BCNU in LEF-2000.