Intranasal delivery of lipid-based nanosystems as a promising approach for brain targeting of the new-generation antiepileptic drug perampanel

Perampanel (PER), a new-generation antiepileptic drug effective against different types of seizures, has already demonstrated a potential in status epilepticus therapy. Considering the growing interest of intranasal (IN) administration for nose-to-brain delivery, PER could be envisioned as a good candidate for this route, especially if formulated in a lipid-based nanosystem. With that purpose, a hydrophobic formulation (FO1.2) and a self-microemulsifying drug delivery system (SMEDDS) (FH5) loaded with PER were developed and characterized. Following PER IN administration (1 mg/kg) to mice, its pharmacokinetics was characterized and compared with intravenous and oral routes. Histopathological toxicity was also examined after a 7-day repeated dose study. FH5 homogeneously formed nanodroplets upon dispersion (20.07 ± 0.03 nm), showing a sustained in vitro PER release profile up to 4 h. By IN route, PER brain delivery was more extensive with FH5 (C_max and AUC of 52.32 ng/g and 190.35 ng.h/g for FO1.2; 93.87 ng/g and 257.75 ng.h/g for FH5). Maximum brain concentration and total brain exposure were higher than those obtained after oral dosage, with maximum PER concentrations reached significantly faster than post-oral administration (15 min vs 2 h). An improvement in PER plasmatic concentration was also obtained, demonstrated by high relative bioavailability values (134.1% for FH5 and 107.8% for FO1.2). PER absolute plasma bioavailability after IN delivery was 55.5% for FH5 and 44.6% for FO1.2, ensuring a somewhat improved targeting of PER to the brain by the IN route compared to the IV route. No signs of toxicity were found by histopathologic evaluation. Results suggest that IN administration of PER might be a feasible and safe approach for acute and chronic epilepsy management, especially using delivery systems as SMEDDS.

Evaluation of the biocompatibility and skin hydration potential of vitamin E-loaded lipid nanosystems formulations: In vitro and human in vivo studies

Lipid-based nanosystems, such as nanostructured lipid carriers (NLC) and nanoemulsions (NE) have been described as promising alternatives to conventional formulations for increase skin hydration. Besides, these systems have been used as efficient vehicles for lipophilic molecules that improve skin properties (e.g. vitamin E). In this study, we performed comparative investigations between hydrogels formulations containing vitamin E-loaded NLC (HG-NLC_VE) and vitamin E-loaded nanoemulsion (HG-NE_VE). The experiments started with particle size measurements, which showed no significant differences between nanoparticles/nanodroplets sizes after incorporation in the hydrogel net (386 nm vs. 397 nm for HG-NLC_VE and 402 nm vs. 514 nm for HG-NE_VE). Afterwards, in vitro biocompatibility studies in human keratinocytes were carried out, being observed that the lipid-based nanosystems were more cytotoxic for the cells before incorporation in the hydrogel. Finally, the formulations hydration potential and sensory attributes for skin application were evaluated by in vitro occlusion tests and in vivo human experiments. The results showed that the HG-NLC_VE exhibited the best occlusive properties, whereas the HG-NE_VE performed a faster skin hydration effect. Furthermore, the latter was selected as the most attractive for skin application, although the HG-NLC_VE was described as more suitable to obtain a long-lasting effect. This study demonstrated the in vitro and in vivo safety and hydration potential of hydrogels containing vitamin E-loaded lipid-based nanosystems. These results establish a basis to assess the cutaneous use of these systems, despite more in vivo experiments, for longer periods and in more volunteers, are required before commercialization.

Nose-to-brain delivery of lipid-based nanosystems for epileptic seizures and anxiety crisis

Epileptic seizures and anxiety crisis are severe conditions that require fast and effective treatment, targeting the brain. Current emergency antiepiletics and anxiolytics have limited brain bioavailability, following oral, intravenous or rectal administration. This relates with the limited extent at which these drugs bypass the blood brain barrier (BBB). Thereby, the development of strategies that significantly improve the brain bioavailability of these drugs, along with a simple and safe administration by patients, attenuating and/or preventing epileptic seizures or anxiety crisis, are still a major need. In this respect, the nasal/intranasal route has been suggested as a promising strategy for drug targeting to the brain, thus avoiding the BBB. Besides, the use of lipid-based nanosystems, such as solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), liposomes, nanoemulsions and microemulsions, have been demonstrating high efficiency for nose-to-brain transport. This review highlights the potential of using lipid-based nanosystems in the management of epilepsy and anxiety, by means of the nasal/intranasal route. So far, the reported studies have shown promising results, being required more in vivo experiments to further advance for clinical trials. Furthermore, toxicological concerns related to the need of evaluate the impairment on the mucociliary clearance mechanism have been pointed.