BackgroundCationic bilayers based on the inexpensive synthetic lipid dioctadecyldimethylammonium bromide (DODAB) have been useful as carriers for drug delivery, immunoadjuvants for vaccines and active antimicrobial agents.MethodsRifampicin (RIF) or isoniazid (ISO) interacted with DODAB bilayer fragments (BF) or large vesicles (LV). Dispersions were evaluated by dynamic light-scattering for zeta-average diameter (Dz) and zeta-potential (ζ) analysis; dialysis for determination of drug entrapment efficiency; plating and CFU counting for determination of cell viability of Mycobacterium smegmatis or tuberculosis, minimal bactericidal concentration (MBC) and synergism index for DODAB/drug combinations.ResultsDODAB alone killed micobacteria over a range of micromolar concentrations. RIF aggregates in water solution were solubilised by DODAB BF. RIF was incorporated in DODAB bilayers at high percentiles in contrast to the leaky behavior of ISO. Combination DODAB/RIF yielded MBCs of 2/2 and 4/0.007 μg/mL against Mycobacterium smegmatis or Mycobacterium tuberculosis, respectively. Synergism indexes equal to 0.5 or 1.0, indicated synergism against the former and independent action, against the latter species.ConclusionsIn vitro, DODAB acted effectively both as micobactericidal agent and carrier for rifampicin. The novel assemblies at reduced doses may become valuable against tuberculosis.
Cada um que passa em nossa vida passa sozinho... porque cada pessoa é única para nós, e nenhuma substitui a outra. Cada um que passa em nossa vida passa sozinho, mas não vai só... Levam um pouco de nós mesmos e nos deixam um pouco de si mesmos. Há os que levam muito, mas não há os que não levam nada. Há os que deixam muito, mas não há os que não deixam nada. Esta é a mais bela realidade da vida...a prova tremenda de que cada um é importante e que ninguém se aproxima do outro por acaso." Saint-Exupéry RESUMO BARBASSA, L. Novas formulações de fármacos tuberculostáticos em dispersões de brometo de dioctadecildimetilamônio: preparação, caracterização e avaliação da atividade in vitro contra micobactérias. 2010. Dissertação
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