Preparation and characterization of poloxamer407-gellan gum based ocular in situ hydrogels for co-delivery of antibiotics and corticosteroids

Abstract

Ocular in situ hydrogels are polymeric solutions that undergo immediate gelation when in contact with the eye. PM407 undergo gelation with increasing the temperature. GE forms a stable gel in the presence of cations of STF. CSNPs, rapidly eliminated from the eye surface by defense mechanisms of the ocular globe. To overcome this issue, nanoparticles can be incorporated into in situ hydrogels to increase the retention time on the ocular surface. Aims This study aimed to synthesize and evaluate DEX-CSNPs, NMS, and PMB-loaded PM407-GE ocular in situ hydrogel. Materials and methods DEX-CSNPs were prepared with ionotropic gelation method. The physicochemical properties of CSNPs were determined by DLS and UV-spectrophotometry. The PM407-GE solutions were prepared by the cold method. The hydrogel's physicochemical properties were characterized by tube inverting test, rheology studies, FT-IR, swelling studies, SEM, in vitro drug release studies, antimicrobial test, and MTT test.

Results DEX-CSNPs showed good properties (size:286 nm, pdi:0.29, zeta potential:20.3, entrapment efficiency (%):29.4 and loading capacity (%):6.5) suitable for ocular administration. The addition of 0.1% GE showed a significant increase in viscosity of PM407. FTIR analysis showed an interaction between functional groups of polymers and drugs. Hydrogels had a porous structure, according to SEM results. In vitro drug release studies and antimicrobial test showed prolonged release of drugs from PM407-GE in situ hydrogel.

Discussion This study provided preliminary evidence that the addition of gellan gum promotes gelation properties of poloxamer 407. hydrogen bondings between functional groups of two polymers and extra gelation capacity of gellan gum at the presence of ions of STF are mainly responsible for this. Drug release studies and antibacterial test revealed that the release of the drugs was prolonged. Therefore, the developed formulation has the potential to be applied as a novel ophthalmic drug carrier.