Intranasal lipid nanocarriers: Uptake studies with fluorescently labeled formulations

Drug delivery by the intranasal route allows both systemic absorption and non-invasive brain targeting, due to the unique connection provided by the olfactory and trigeminal nerves between the brain and the external environment. Lipid nanocarriers can improve intranasal drug delivery by enhancing bioadhesion to nasal mucosa, and by protecting the encapsulated drug from biological degradation and transport efflux proteins.

Highlights

Role of lipid nanocarriers for intranasal drug delivery is controversial.

Lipophilic fluorophores used as model drugs loaded in lipid nanocarriers.

Water solubility of loaded compounds affects systemic or nose-to-brain absorption.

In this study two different biocompatible lipid nanocarriers were compared: nanoemulsions and solid lipid nanoparticles. The nasal uptake was investigated by labeling the nanocarriers lipid matrix with two fluorescent probes, 6-coumarin and rhodamine B, both lipophilic, yet characterized by different water solubility, in order to mimic the behavior of hypothetic drug compounds.

Ex vivo permeation, in vivo pharmacokinetics and biodistribution studies were performed. 6-coumarin, water insoluble and therefore integral with the lipid matrix, was taken up to a limited extent, within a long timeframe, but with a proportionally more pronounced brain accumulation. In nanoemulsions soluble rhodamine B showed a relevant systemic uptake, with good bioavailability, likely due to the prompt release of the probe at the nasal mucosa.

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Article information: Elisabetta Muntoni, Elisabetta Marini, Chiara Ferraris, Sara Garelli, Maria Teresa Capucchio, Elena Colombino, Pier Paolo Panciani, Luigi Battaglia, Intranasal lipid nanocarriers: Uptake studies with fluorescently labeled formulations, Colloids and Surfaces B: Biointerfaces, Volume 214, 2022, 112470, ISSN 0927-7765, https://doi.org/10.1016/j.colsurfb.2022.112470.