Clinical pharmacokinetics of atropine oral gel formulation in healthy volunteers.

Sialorrhea or drooling is a common problem in children and adults with neurodevelopmental disorders. It can negatively impact the quality of life due to its physical and psychological manifestations. Providers commonly prescribe atropine eye drops for topical administration to the oral mucosa, as an off-label treatment to manage sialorrhea. However, the off-label use of atropine eye drops can be associated with medication and dosing errors and systemic side effects. To address these limitations of treatment, we developed a mucoadhesive topical oral gel formulation of atropine as an alternative route to off-label administration of atropine eye drops. In this clinical pharmacokinetic (PK) study, we evaluated the safety and PK of atropine gel (0.01% w/w) formulation after single-dose administration to the oral mucosa in 10 healthy volunteers. The PK data showed that after topical administration to the oral mucosa, atropine followed a two-compartment PK profile. The maximum plasma concentration and area under the curve extrapolated to infinite time were 0.14 ng/mL and 0.74 h·ng·mL -1 , respectively. The absorption rate constant calculated by the compartmental analysis was 0.4 h -1 . Safety parameters, such as heart rate, blood pressure, and oxygen saturation, did not significantly change before and after administration of the gel formulation, and no adverse events were observed in all participants who received atropine gel. These data indicate that atropine gel formulation has a satisfactory PK profile, is well-tolerated at the dose studied, and can be further considered for clinical development as a drug product to treat sialorrhea.