Development and Comparative In Vitro and In Vivo Study of BNN27 Mucoadhesive Liposomes and Nanoemulsions for Nose-to-Brain Delivery

In-depth Mechanism, Challenges, and Opportunities of Delivering Therapeutics in Brain Using Intranasal Route

Central nervous system-related disorders have become a continuing threat to human life and the current statistic indicates an increasing trend of such disorders worldwide. The primary therapeutic challenge, despite the availability of therapies for these disorders, is to sustain the drug's effective concentration in the brain while limiting its accumulation in non-targeted areas. This is attributed to the presence of the blood-brain barrier and first-pass metabolism which limits the transportation of drugs to the brain irrespective of popular and conventional routes of drug administration. Therefore, there is a demand to practice alternative routes for predictable drug delivery using advanced drug delivery carriers to overcome the said obstacles. Recent research attracted attention to intranasal-to-brain drug delivery for promising targeting therapeutics in the brain. This review emphasizes the mechanisms to deliver therapeutics via different pathways for nose-to-brain drug delivery with recent advancements in delivery and formulation aspects. Concurrently, for the benefit of future studies, the difficulties in administering medications by intranasal pathway have also been highlighted.

Research progress in brain-targeted nasal drug delivery

The unique anatomical and physiological connections between the nasal cavity and brain provide a pathway for bypassing the blood-brain barrier to allow for direct brain-targeted drug delivery through nasal administration. There are several advantages of nasal administration compared with other routes; for example, the first-pass effect that leads to the metabolism of orally administered drugs can be bypassed, and the poor compliance associated with injections can be minimized. Nasal administration can also help maximize brain-targeted drug delivery, allowing for high pharmacological activity at lower drug dosages, thereby minimizing the likelihood of adverse effects and providing a highly promising drug delivery pathway for the treatment of central nervous system diseases. The aim of this review article was to briefly describe the physiological structures of the nasal cavity and brain, the pathways through which drugs can enter the brain through the nose, the factors affecting brain-targeted nasal drug delivery, methods to improve brain-targeted nasal drug delivery systems through the application of related biomaterials, common experimental methods used in intranasal drug delivery research, and the current limitations of such approaches, providing a solid foundation for further in-depth research on intranasal brain-targeted drug delivery systems (see Graphical Abstract).

Preparation of mucoadhesive methacrylated chitosan nanoparticles for delivery of ciprofloxacin

Mucoadhesive polymers and their nanoparticles have attracted a lot of attention in pharmaceutical applications, especially transmucosal drug delivery (TDD). Mucoadhesive polysaccharide-based nanoparticles, particularly chitosan, and its derivatives, are widely used for TDD owing to their outstanding features such as biocompatibility, mucoadhesive, and absorption-enhancing properties. Herein, this study aimed to design potential mucoadhesive nanoparticles for the delivery of ciprofloxacin based on methacrylated chitosan (MeCHI) using the ionic gelation method in the presence of sodium tripolyphosphate (TPP) and compared them with the unmodified chitosan nanoparticles. In this study, different experimental conditions including the polymer to TPP mass ratios, NaCl, and TPP concentration were changed to achieve unmodified and MeCHI nanoparticles with the smallest particle size and lowest polydispersity index. At 4:1 polymer /TPP mass ratio, both chitosan and MeCHI nanoparticles had the smallest size (133 ± 5 nm and 206 ± 9 nm, respectively). MeCHI nanoparticles were generally larger and slightly more polydisperse than the unmodified chitosan nanoparticles. Ciprofloxacin-loaded MeCHI nanoparticles had the highest encapsulation efficiency (69 ± 13 %) at 4:1 MeCHI /TPP mass ratio and 0.5 mg/mL TPP, but similar encapsulation efficiency to that of their chitosan counterpart at 1 mg/mL TPP. They also provided a more sustained and slower drug release compared to their chitosan counterpart. Additionally, the mucoadhesion (retention) study on sheep abomasum mucosa showed that ciprofloxacin-loaded MeCHI nanoparticles with optimized TPP concentration had better retention than the unmodified chitosan counterpart. The percentage of the remained ciprofloxacin-loaded MeCHI and chitosan nanoparticles on the mucosal surface was 96 % and 88 %, respectively. Therefore, MeCHI nanoparticles have an excellent potential for applications in drug delivery.