Solid lipid nanoparticles as a novel formulation approach for tanespimycin (17-AAG) against leishmania infections: Preparation, characterization and macrophage uptake.

17-N-allylamino-17-demethoxygeldanamycin (17-AAG, tanespimycin) is an inhibitor of heat shock protein 90 (Hsp90), which has been studied in the treatment of cancer such as leukemia or solid tumors. Alternatively, 17-AAG may represent a promising therapeutic agent against leishmaniasis. However, the delivery of 17-AAG is difficult due to its poor aqueous solubility. For exploring the therapeutic value of 17-AAG, we developed solid lipid nanoparticles (SLN) by double emulsion method. SLN exhibited ~100 nm, PDI < 0.2 and zeta potential ~20 mV. In addition, SLN were morphologically spherical with negligible aggregation. The entrapment efficiency of 17-AAG into the lipid matrix reached at nearly 80%. In a separate set of experiments, fluorescent SLN (FITC-labeled) showed a remarkable macrophage uptake, peaking within 2 h of incubation by confocal microscopy. Regarding the drug internalization as critical step for elimination of intracellular Leishmania, this finding demonstrates an important feature of the developed SLN. Collectively, these data indicate the feasibility of developing SLN as potential delivery systems for 17-AAG in leishmaniasis chemotherapy.

Desenvolvimento de nanoformulações de uso tópico contendo Anfotericina B e Clorito de sódio para Leishmaniose Tegumentar

American Cutaneous Leishmaniasis (ACL) is a polymorphic disease of the skin and mucosa caused by the parasite of the genus Leishmania. Treatment options have limitations, especially toxicity and drug esistance,compromising the safety and efficacy of the therapy. The search for a topical treatment is recommended by the WHO. Amphotericin B (Anf- B) is a polyene antibiotic, already used in the treatment of ACL in the form of intravenous lipid preparations, including liposomes. Sodium chlorite (NaClO2) has been nvestigated for its oxidative potential and healing action on lesions caused by L. tropica. OBJECTIVE. The present work investigates the potential of the Anf-B / NaClO2 association as a basis for a new treatment of LTA from topical nanoformulations containing these agents. MATERIAL AND METHODS. The NaClO2 and Anf-B cytotoxicity assays were performed against axenic promastigotes of L. braziliensis (MHOM / BR / 01 / BA788) for IC50 determination of these compounds. To evaluate the combined effect, NaClO2 and Anf-B were tested according to the modified fixed ratio method (1: 1, 1: 5, 5: 1). In addition, the cell viability of peritoneal macrophages of BALB / c mice and human keratinocytes (HaCaT) was evaluated in the presence of each individual treatment and CC50 was calculated. These tests were performed using Alamar blue® colorimetric method. NaClO2 activity was evaluated alone and in Combination with Anf-B on L.braziliensis-infected macrophages. The activity of NaClO2 was evaluated on the viability of axenic amastigotes of L.braziliensis, using the colorimetric method of Alamar blue®. SEM and TEM images were obtained from promastigotes and axenic amastigotes treated with 14 ìM NaClO2. Semisolid formulations were developed containing Anf-B in solid lipid nanoparticles (NLS) and free. In vitro release study of the drug in Franz cells was performed for a period of 12 hours (0, 30min, 1h, 2h, 4h, 6h, 8h and 12h). Stability studies of these formulations were performed over a period of 14 days. RESULTS. The results demonstrate that NaClO2 and Anf-B presented a mean IC50 of 9.66 ìM and 0.11 ìM,respectively, on the romastigote forms after 72 h of culture. SEM and TEM images suggest na activity on the increase of oxidative stress of NaClO2 on promastigotes. The combination of the two compounds resulted in an additive effect with na average combination index of 0.98 ± 0.09.Regarding cell viability assays, NaClO2 and Anf-B presented CC50 values of 856.3 ìM and> 50 ìM, respectively. The selectivity index of NaClO2 was estimated at 88.6 and Anf-B> 454.5.NaClO2 showed no activity on the viability of intracellular and extracellular amastigotes, which was reinforced by SEM and TEM images. In vitro release studies on Franz cells demonstrated that Anf-B was released more slowly and gradually when in a nanostructured system and all formulations remained stable over 14 days. CONCLUSIONS. For the first time, this work demonstrated the activity of NaClO2 in New World Leishmania. Additionally, it presented the pharmacotechnical potential of nanoformulations containing Anf-B for the treatment of ACL.