Atovaquone and rifabutine-loaded nanocapsules: Formulation studies

Atovaquone and rifabutine have potential therapeutic activity against toxoplasmosis but the low water solubility of these drugs reduces their bioavailability. Their formulation as a colloidal suspension of poly (D,L) lactic acid nanocapsules can increase that effectiveness. The atovaquone formulation was more stable than the rifabutine one and was injected at 15 mg/kg per day by the intragastric route to mice infected with Toxoplasma gondii. A better survival rate was observed in mice treated with nanocapsules than in mice treated with a suspension of the drug. Parasites were undetectable in brains of mice treated with atovaquone nanocapsules one month previously whereas control mice treated with drug suspension showed signs of central nervous system infection. (C) 1997 Elsevier Science B.V.