ABSTRACT
Cross-linked polymers exhibit three-dimensional networks. They are prepared from synthetic polymers, carbon-based materials such as fullerenes, graphene oxide, carbon nanotubes, and natural polymers. An in situ gel is a good example of a cross-linked polymer. The delivery of therapeutics to the eye with topical eye drops is characterized by low bioavailability. Several constraints, which could be classified as anatomical and physiological, such as tear turnover, nasolacrimal drainage, reflex blinking, and ocular static and dynamic barriers hinder deeper ocular drug permeation. Delivery of therapeutics to the vaginal area is challenging due to vast physiological variations, such as differences in pH, microflora, changes during menstruation, and cervical mucus. The formulation was pH and temperature sensitive with the capability to undergo a sol-gel transition at physiological temperature and pH. The nasal turbinates are responsible for the turbulent airflow through the nasal passages, thereby resulting in a good contact between the inhaled air and the mucosal surface found in the respiratory region.
