The Pharmacokinetics of Drug Delivery to the Upper Nasal Space: A Review of INP105 Development

Abstract

Nasal drug delivery presents a potential opportunity for achieving rapid, extensive drug absorption via a nonoral route by 1) avoiding degradation within the gastrointestinal tract and first-pass metabolism in the liver and 2) facilitating faster onset via rapid absorption into the bloodstream. However, the site of drug deposition within the nasal cavity may impact drug pharmacokinetics. Precision Olfactory Delivery (POD®) by Impel Pharmaceuticals Inc. is a new technology that provides handheld, manually actuated, propellant-powered drug delivery to the upper nasal space for rapid and efficient absorption. Rapid onset of effect can be a major advantage in many clinical applications where quick and effective administration is needed (eg, alleviating agitation in emergency settings or reducing debilitating migraine symptoms). Here, we review the pharmacokinetic profile of INP105, which is being developed to deliver olanzapine (OLZ) by POD to treat agitation in patients with autism. Because formulation can play a large role in the pharmacokinetic profile of a nasally administered drug, we provide a comprehensive review of both published and previously unpublished preclinical data outlining how the INP105 formulation was developed and optimized for study in humans. Multiple formulation carriers and excipients were tested to find a stable INP105 formulation with a desirable nasal absorption profile. Because the nasal architecture in nonhuman primates (NHPs) is similar to humans, the pharmacokinetics and tolerability of an INP105 combination product (NHP-INP105) using a clinical formulation combined with a device specifically designed for NHPs has been investigated in preclinical NHP studies, providing translational data for human studies and the pathway for testing novel products and formulations. The pharmacokinetics and tolerability of INP105 were then evaluated in an early clinical study in humans, demonstrating favorable pharmacokinetic and pharmacodynamic profiles. In this review, we aim to illustrate how delivery of therapeutics to the upper nasal space using POD, such as with agents like INP105, has the potential to optimize nasal delivery and unlock the potential of delivery-limited drugs to provide patients with rapid onset of effect, ease of use, and convenience.