FORMULACOES LIPOSSOMICAS CONTENDO VIDARABINA E/OU DERIVADOS, COM INDICE TERAPEUTICO ELEVADO E PROCESSO PARA A SUA PREPARACAO

The invention refers to liposomal formulations containing vidarabine, vidarabine monophosphate or another vidarabine derivative as pharmacological active substance, for clinical use, comprising drug/lipid ratios of at least 5 mmol/mmol, lipidic compositions made by mixtures of phospholipids of saturated or unsaturated acyl chains, with, optionally, cholesterol and charged molecules (of lipidic nature or not), the size of liposomes ranging from 0.01 mm to 5 mm and encapsulation efficiencies typically up to 100 %. The vidarabine (or derivative) liposomal formulations are highly stable either in lyophilized state or upon reconstitution. The vidarabine (or derivative) liposomal formulations are nontoxic and nonimmunogenic when administered to animals and increase the residence time of drug in bloodstream, increase the drug delivery and accumulation at the liver (either in hepatocytes or in Kupffer cells) and spleen and increase the therapeutic index of the antiviral agent. The invention also refers to a process for the preparation of liposomal formulations comprising forming multilamellar liposomes containing vidarabine (or derivative) and subjecting the liposomes to lyophilization, controlled rehydration and, optionally, extrusion under pressure. After preparation, formulations are again subjected to lyophilization in presence of a cryoprotectant and stored under vacuum at 4 DEG C.