The in vitro transport of dihydroergotamine across porcine nasal respiratory and olfactory mucosa and the effect of a novel powder formulation

The objective was to investigate the transport of dihydroergotamine (DHE) across porcine nasal respiratory and olfactory mucosa and to evaluate the absorption enhancing effect of a novel dry powder formulation compared with a reference solution with the horizontal Ussing chamber method. The powder formulation was obtained by mixing micronized DHE particles and mucoadhesive carrier particles (sodium starch glycolate) to create an interactive mixture. The horizontal Ussing chamber method was chosen as the in vitro model since it provides the opportunity to apply a dry powder formulation and compare the transport across the two types of nasal mucosa. A histological evaluation confirmed that the mucosa had been correctly isolated. The results showed no significant difference in the absorption from the powder formulation compared with the reference solution, but the transport of DHE was significantly higher across olfactory mucosa than across respiratory mucosa. This may be explained by facilitated transport through paracellular transfer along the olfactory nerve cells.