Dexamethasone (DXM) and methylprednisolone (MEP) are potent glucocorticoids used to control several inflammatory conditions. Evidence of delayed DXM reaching the central nervous system (CNS) as well as tachyphylaxis and systemic, undesirable side effects are the main limitations of peripheral delivery. Intranasal administration offers direct access to the brain as it bypasses the blood–brain barrier. The Mucosal Atomization Device is an optimal tool that can achieve rapid absorption into the CNS and the bloodstream across mucosal membranes. This study was designed to evaluate and compare the bioavailability of DXM and MEP after intranasal versus intravenous administration. Two open-label, balanced, randomized, two-treatment, two-period, two-sequence, single-dose, crossover studies were conducted, which involved healthy male and female adult volunteers. After intranasal administration, DXM and MEP were detected in plasma after the first sampling time. Mean peak concentrations of DXM and MEP were 86.61 ng/mL at 60 min and 843.2 ng/mL at 1.5 h post-administration, respectively. DXM and MEP showed high absolute bioavailability, with values of 80% and 95%, respectively. No adverse effects were observed. DXM and MEP systemic bioavailability by intranasal administration was comparable with the intravenous one, suggesting that the intranasal route can be used as a non-invasive and appropriate alternative for systemic drug delivery.

Inhalants are chemical substances that induce intoxication, and toluene is the main component of them. Increasing evidence indicates that a dependence on inhalants involves a state of chronic stress associated to the activation of immune cells in the central nervous system and release of proinflammatory mediators, especially in some brain areas such as the nucleus accumbens and frontal cortex, where the circuits of pleasure and reward are. In this study, anti-neuroinflammatory treatment based on a single dose of intranasal methylprednisolone was assessed in a murine model of chronic toluene exposure. The levels of proinflammatory mediators, expression levels of Iba-1 and GFAP, and histological changes in the frontal cortex and nucleus accumbens were evaluated after the treatment. The chronic exposure to toluene significantly increased the levels of TNF-α, IL-6, and NO, the expression of GFAP, and induced histological alterations in mouse brains. The treatment with intranasally administered MP significantly reduced the expression of TNF-α and NO and the expression of GFAP (p < 0.05); additionally, it reversed the central histological damage. These results indicate that intranasally administered methylprednisolone could be considered as a treatment to reverse neuroinflammation and histological damages associated with the use of inhalants.

No abstract

The genus Galphimia is widely distributed in Mexico, and is represented by 22 species, including medicinal species. The sedative and anti-inflammatory effects of galphimines produced by the species Galphimia glauca have been documented. Formerly, molecular studies using DNA barcodes demonstrated that nine populations botanically classified as Galphimia glauca belong to four different species of the genus Galphimia, and that only one exhibited the sedative properties; however, all the collected species showed anti-inflammatory activity. Other bioactive compounds like quercetin, galphins, galphimidins and glaucacetalins have been identified from methanolic extracts of plants botanically classified as Galphimia glauca. The aim of this work was to determine the anti-inflammatory activity of methanolic extracts of nine collected Galphimia spp. populations grown in Mexico. The possible modes of action were analyzed by evaluating the inhibition of LPS-induced inflammation processes both in vitro and in vivo. The nine populations were evaluated by an in vitro model using RAW 264.7 murine macrophage cells, and two populations (a galphimine-producing and a non-galphimine-producing population) were selected for the in vivo experiments of systemic inflammation and neuroinflammation in mice. Results suggest that an anti-inflammatory in vitro effect was present in all the studied populations, evidenced by the inhibition of nitrite production. An inhibitory systemic inflammation in mice was exerted by the two analyzed populations. In the neuroinflammation model, the anti-inflammatory effect was demonstrated in methanolic extract of the non-galphimine-producing population. For the populations of Galphimia spp. studied herein, the anti-inflammatory effect could not be correlated to the presence of galphimines.