Epinephrine in Anaphylaxis: Preclinical Study of Pharmacokinetics after Sublingual Administration of Taste-Masked Tablets for Potential Pediatric Use

Abstract

Epinephrine is a life-saving treatment in anaphylaxis. In community settings, a first-aid dose of epinephrine is injected from an auto-injector (EAI). Needle phobia highly contributes to EAI underuse, leading to fatalities—especially in children. A novel rapidly-disintegrating sublingual tablet (RDST) of epinephrine was developed in our laboratory as a potential alternative dosage form. The aim of this study was to evaluate the sublingual bioavailability of epinephrine 30 mg as a potential pediatric dose incorporated in our novel taste-masked RDST in comparison with intramuscular (IM) epinephrine 0.15 mg from EAI, the recommended and only available dosage form for children in community settings. We studied the rate and extent of epinephrine absorption in our validated rabbit model ( n = 5) using a cross-over design. The positive control was IM epinephrine 0.15 mg from an EpiPen Jr ^®. The negative control was a placebo RDST. Tablets were placed under the tongue for 2 min. Blood samples were collected at frequent intervals and epinephrine concentrations were measured using HPLC with electrochemical detection. The mean ± SEM maximum plasma concentration ( C _max) of 16.7 ± 1.9 ng/mL at peak time ( T _max) of 21 min after sublingual epinephrine 30 mg did not differ significantly ( p > 0.05) from the C _max of 18.8 ± 1.9 ng/mL at a T _max of 36 min after IM epinephrine 0.15 mg. The C _max of both doses was significantly higher than the C _max of 7.5 ± 1.7 ng/mL of endogenous epinephrine after placebo. These taste-masked RDSTs containing a 30 mg dose of epinephrine have the potential to be used as an easy-to-carry, palatable, non-invasive treatment for anaphylactic episodes for children in community settings.