No abstract

carrier system is delivering the active ingredient(s) to the target site of action in a safe, effective and efficient way to elicit its pharmacological effect. [1,2] Precisely, the drug should arrive at the disease site at the right time in a controlled manner. Topical eye formulations are the most convenient and accepted ocular delivery systems for treating eye diseases accounting for up to 90% of ophthalmic medicines. [3] However, only 5% of the instilled dose penetrates into the deeper ocular tissues while the larger percentage gets lost through rapid eye blinking, tear turnover, and nasolacrimal drainage. Hence, making it extremely difficult to achieve therapeutic drug concentration following topical eye instillation. [4] To overcome these challenges, numerous works have been reported in the literature and various strategies implemented to improve ocular bioavailability and retention time. [5-7] Several formulations and novel carrier systems have been designed, for example, in situ forming gel system, [8,9] microemulsions, [10,11] and liposomes, [12,13] which are specifically designed to achieve favorable residence time and sustained drug release. Though the use of these technologies has opened the door for more specific and targeted delivery systems, the number of the novel ocular products entering into the market is very slow In this work, a 2D nanosheet (NS) of γ-cyclodextrin (CD)-based metalorganic frameworks (MOFs) is synthesized through a facile green chemistry approach. NS-MOF carrier is constructed using a water system in a simple one-pot reaction involving CD and potassium carbonate. Particle size optimization is achieved by adjusting the reaction temperature and the introduction of crystal growth suppressor (appropriate proportion of acetone). The NS-MOF stability in aqueous medium is improved by polymerization reaction of crosslinked CD-MOF (CL-CD-MOF) without blocking its cavity for drug loading. The effects of particle geometry and size of nanoporous materials on their pharmacokinetics during drug delivery are compared between the sheetlike DXM@CL-NS-MOF and 3D-cubic-shaped DXM@CL-CD-MOF loaded with the same quantity of dexamethasone (DXM). The bioefficiency of these carriers in tear fluids and aqueous humors to deliver DXM is investigated in vivo. The results demonstrate that the 2D-nanosheet particles significantly improve precorneal residence time and intraocular bioavailability over the commercial Maxidex (0.1% dexamethasone) and its 3D-cubes counterpart of similar chemical composition. It suggests that the geometry of a carrier play a significant role in the biodistribution, and the carrier of CL-NS-MOF is a good candidate for ocular drug delivery.