Despite its proven efficacy, most older children and adults object to this route of administration. As a result, many patients do not realize the benefit of a therapy that can improve outcomes and decrease healthcare costs. Intranasal administration of benzodiazepines offers a potential alternative. The primary objective of this study was to compare the bioavailability and pharmacokinetics of two novel intranasal (IN) diazepam (DZP) formulations versus intravenous (IV) administration in healthy volunteers. Twenty-four healthy volunteers were randomized into an open-label, three-way crossover study. 10mg doses of two investigational intranasal DZP formulations (solution, suspension) and a 5mg IV dose of commercially available DZP injectable, USP were given. A two-week washout period separated treatments. Plasma samples for DZP analysis were collected pre-dose and at regular intervals up to 240h post-dose. DZP concentration-time data were analyzed using a non-compartmental pharmacokinetics approach. Exposure following administration of DZP IN solution (absolute bioavailability - 97%) was greater than the IN suspension (absolute bioavailability - 67%). Mean Cmaxvalues for the suspension and solution formulations were 221ng/mL and 272ng/mL, respectively. Median time to maximum concentration (Tmax) was 1h and 1.5h for suspension and solution formulation, respectively. Both investigational intranasal formulations were well tolerated. The results of this pilot study indicate that development of an intranasal diazepam formulation with high bioavailability, reasonable variability, and good tolerability is feasible.
Bibliographical noteFunding Information:
We would like to acknowledge Neurelis Inc., for providing the study drug and also for their financial support towards this study. We would like to acknowledge William Kramer, Kramer Consulting LLC for assistance with analysis of the data. Plasma diazepam concentrations were determined by LC/MS/MS at ICON Development Solutions LLC.
- Acute repetitive seizures
- Intranasal therapy
- Seizure emergencies