Metastatic Melanoma: A Preclinical Model Standardization and Development of a Chitosan-Coated Nanoemulsion Containing Temozolomide to Treat Brain Metastasis.

Melanoma is the most aggressive type of skin cancer. Brain metastasis is the worst scenario in metastatic melanoma and the treatment options for these patients are limited. Temozolomide (TMZ) is a chemotherapy agent used to treat primary central nervous system tumors. Our objective was to develop chitosan-coated nanoemulsion containing temozolomide (CNE-TMZ) for nasal route administration to melanoma brain metastasis treatment. A preclinical model of metastatic brain melanoma was standardized, and the efficiency of the developed formulation was further determined in vitro and in vivo. The nanoemulsion was done by spontaneous emulsification method and the formulation was characterized by size, pH, polydispersity index, and zeta potential. Culture assessments to determine cell viability were done in the A375 human melanoma cell line. To determine the safety of formulation, healthy C57/BL6 mice were treated with a nanoemulsion without TMZ. The model in vivo used B16-F10 cells implanted by stereotaxic surgery in C57/BL6 mice brains. The results demonstrate that the preclinical model used showed to be useful to analyze the efficiency of new candidate drugs to treat melanoma brain metastasis. The chitosan-coated nanoemulsions with TMZ showed the expected physicochemical characteristics and demonstrated safety and efficacy, reducing around 70% the tumor size compared to control mice, and presenting a tendency in mitotic index reduction, becoming an interesting approach to treat melanoma brain metastasis.

Nasal administration of a temozolomide-loaded thermoresponsive nanoemulsion reduces tumor growth in a preclinical glioblastoma model.

Glioblastoma (GB) is the worst and most common primary brain tumor. Temozolomide (TMZ), an alkylating agent, is widely used for treating primary and recurrent high-grade gliomas. However, at least 50% of TMZ treated patients do not respond to TMZ and the development of chemoresistance is a major problem. Here, we designed a lipid nanoemulsion containing a thermoresponsive polymer (poloxamer 407) aiming to improve TMZ release into the brain via nasal delivery. Increasing amounts of poloxamer 407 were added to preformed nanoemulsions (250 nm-range) obtained by spontaneous emulsification. The influence of the polymer concentration (from 2.5% to 12.5%) and temperature on viscosity was clearly evidenced. Such effect was also noticed on the mucoadhesiveness of formulations, as well as TMZ release rate and retention/permeation through nasal porcine mucosa using Franz-type diffusion cells. From these results, a formulation containing 10% of poloxamer (NTMZ-P10) was selected for further experiments by nasal route. A significantly higher TMZ amount was observed in the brain of rats from NTMZ-P10 in comparison with controls. Finally, our results show that formulation reduced significantly tumor growth by three-fold: 103.88 ± 43.67 mm3 (for NTMZ-P10) and 303.28 ± 95.27 mm3 (control). Overall, these results suggest the potential of the thermoresponsive formulation, administered by the non-invasive nasal route, as a future effective glioblastoma treatment.

Chitosan-coated rosmarinic acid nanoemulsion nasal administration protects against LPS-induced memory deficit, neuroinflammation, and oxidative stress in Wistar rats.

Rosmarinic acid (RA) lipid-nanotechnology-based delivery systems associate with mucoadhesive biopolymers for nasal administration has arisen as a new promising neuroprotective therapy for neurodegenerative disorders (ND). We have previously demonstrated the glioprotective effect of chitosan-coated RA nanoemulsions (RA CNE) against lipopolysaccharide (LPS)-induced damage in rat astrocyte primary culture. Here, we further investigate the protective effect of RA CNE nasal administration on LPS-induced memory deficit, neuroinflammation, and oxidative stress in Wistar rats, since these in vivo studies were crucial to understand the impact of developed delivery systems in the RA neuroprotective effects. The animals were treated through nasal route with RA CNE (2 mg·mL-1), free RA (2 mg·mL-1), blank CNE, and saline (control and LPS groups) administrations (n.a., 100 µL per nostril) twice a day (7 a.m./7 p.m.) for six days. On the sixth day, the animals received the last treatments and LPS was intraperitoneally (i.p.) administrated (250 µg·kg-1). Overall results, proved for the first time that the RA CNE nasal administration elicits a neuroprotective effect against LPS-induced damage, which was associated with increased 1.6 times recognition index, decreased 5.0 and 1.9 times in GFAP+ cell count and CD11b expression, respectively, as well as increased 1.7 times SH in cerebellum and decreased 3.9 times TBARS levels in cerebral cortex in comparison with LPS group. RA CNE treatment also facilitates RA bioavailability in the brain, confirmed by RA quantification. Free RA also demonstrates a protective effect in some studied parameters, although no RA was quantified in the brain.