Liposomal Formulations for Nose-to-Brain Delivery: Recent Advances and Future Perspectives

Restricted drug entry to the brain that is closely associated with the existence of the blood brain barrier (BBB) has limited the accessibility of most potential active therapeutic compounds to the brain from the systemic circulation. Recently, evidences for the presence of direct nose-to-brain drug transport pathways have been accumulated by several studies and an intranasal drug administration route has gained attention as a promising way for providing direct access to the brain without the needs to cross to the BBB. Studies aiming for developing nanoparticles as an intranasal drug carrier have shown considerable promise in overcoming the challenges of intranasal drug delivery route. This review gives a comprehensive overview of works having investigated liposomes as a potential vehicle to deliver drugs to the brain through nose-to-brain route while considering the excellent biocompatibility and high potential of liposomes for clinical development. Herein, studies are reviewed with special emphasis on the impact of formulation factors, such as liposome composition and surface modification of liposomes with targeting moieties, in addition to intranasal environmental factors that may affect the extent/site of absorption of intranasally administered, liposome-encapsulated drugs.

Strategies for nose-to-brain drug delivery

"Intranasal drug administration is an effective method that has shown promise for delivering drugs directly to the brain. This approach is associated with many challenges, and efficacy in bypassing blood-brain barrier (BBB) is debated. This review describes the pathways of nose-to-brain drug delivery, physicochemical drug properties that influence drug uptake through the nasal epithelium, physiological barriers, methods to enhance nose-to-brain absorption, drug bioavailability and biodistribution, and intranasal devices for nose-to-brain drug delivery. The mechanism of each device is described and supporting evidence from clinical trials is presented. This paper summarizes strategies involved in nose-to-brain drug delivery and provides evidence of potential efficacy of nose-braindelivery from clinical trials."

The Intranasal Route as an Alternative Method of Medication Administration

Intranasal drug administration is a less invasive method of drug delivery that is easily accessible for adult and pediatric patients. Medications administered by the intranasal route have efficacy comparable to intravenous administration and typically have superior efficacy to subcutaneous or intramuscular routes. The intranasal route is beneficial in emergent situations when the intravenous route is not available. The intranasal route is safe and effective in various indications, and therapeutic systemic concentrations of medication can be attained via this route. As the evidence for and comfort with intranasal administration continue to grow, guidance on correct technique, medications, and dosing is vital for appropriate use. This article reviews the process and practices of appropriate intranasal medication administration.