Advances in nasal drug delivery systems

Abstract

Nasal drug delivery has been around for centuries and employed both leisure and recreations and also for the treatment of various conditions such as migraine, decongestion, sinusitis, rhinitis, and in emergency. The route is convenient and popular. It has numerous advantages such as direct delivery to the (central nervous system) CNS, high bioavailability, large surface area, needles are not used, and no special skills are required to deliver the drug. The method is non-invasive and provides direct drug transfer from nose to brain via olfactory nerve, hence it bypasses the blood-brain barrier for CNS effect and first pass effect while drug absorbed via nasal mucosa for systemic effect. It is also suitable for drugs that are unstable in an acid environment. The two main mechanisms in nasal drug delivery are discussed along with various factors involved such as physicochemical properties of the drug, formulations factors, and the physiological and anatomical characteristics. Various barriers effecting nasal drug delivery are also discussed. The delivery of microspheres and liposome formations using various nasal devices is also discussed.