Vesicular carriers for direct nose-to-brain drug delivery

Abstract The nasal route of administration is gaining a lot of interest these days in order to achieve the efficient brain targeting. The superior therapeutic outcomes of nasal delivery are due to surpassing the demerits of the conventional drug delivery viz. first-pass metabolism, enzymatic degradation in gastric environment, poor absorption rate, and reduced bioavailability. This route suffers several drawbacks viz. mucociliary clearance, reduced residence time, and poor permeability through nasal mucosa, which made it difficult task for the formulators to fabricate the efficient nasal delivery system. The intranasal delivery extends various merits over systemic drug delivery because it directly allows the entry of drug in the brain via olfactory route and trigeminal nerve pathways. In addition, the amount of drug in the olfactory bulb enhances the drug bioavailability and cuts down the drug degradation and loss through systemic clearance. Currently, many vesicular carriers (liposomes, niosomes, ethosomes, transferosomes, virosomes, and novasomes) have shown promising outcomes to encounter the drawbacks of nasal route of drug administration. This chapter includes brief discussion on the above-mentioned vesicular carriers along with their difference in structure, composition, physicochemical properties, penetrability, and drug entrapment efficiency. The efforts taken by the researchers to develop vesicular carriers with an aim to obtain nose-to-brain delivery need a lot more thrust. This chapter also includes the clinical translational updates of various formulations and challenges encountered.