Chitosan/β-glycerophosphate in situ forming thermo-sensitive hydrogel for improved ocular delivery of moxifloxacin hydrochloride

• Published in: European journal of pharmaceutical sciences Vol. 167; p. 106041
• Main Authors: Asfour, Marwa Hasanein, Abd El-Alim, Sameh Hosam, Awad, Ghada Elsayed Ahmed, Kassem, Ahmed Alaa
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2021
• Subjects: Chitosan; Moxifloxacin HCL; Ocular delivery; Staphylococcus aureus; Thermo-sensitive hydrogel; β-glycerophosphate; Moxifloxacin HCL; β-glycerophosphate; Chitosan; Ocular delivery; Staphylococcus aureus; Thermo-sensitive hydrogel
• ISSN: 0928-0987; 1879-0720
• DOI: 10.1016/j.ejps.2021.106041

The aim of the current work is to develop a thermo-sensitive hydrogel system of moxifloxacin hydrochloride (MOX) for improved ocular delivery. Fifteen formulations were prepared at different concentrations of β-glycerophosphate disodium salt (β-GP) 12–20% (w/v) and chitosan (CS) 1.7–1.9% (w/v). The optimized MOX loaded thermo-sensitive hydrogel system (F8), consisting of CS (1.8%, w/v) and β-GP (16%, w/v), showed optimum gelation temperature (35 °C) and gelation time (2 min), thus was selected for further investigations. It showed a significant decrease (p < 0.05) in the zeta potential value compared to CS solution with a favorable pH value (7.1) and confirmed thermoreversible behavior. MOX loaded F8 displayed a porous structure under scanning electron microscopy. Rheological investigation of MOX loaded F8 revealed the presence of a strong hydrogel network with high elasticity along with a small loss factor of 0.08 indicating a great ease of gel formation. The release of MOX from F8 was found to be governed by a combined mechanism of diffusion and relaxation. Biological assessment of two concentrations of MOX loaded F8 (0.25 and 0.5%) was conducted using healthy and infected male albino New Zealand rabbits, where an improved and prolonged antibacterial activity against Staphylococcus aureus compared to plain MOX (0.5%), marketed MOX eye drops (0.5%), was shown. Moreover, histopathological examination of ocular tissues confirmed the antibacterial efficacy of the optimized formulation eight days post topical therapy. Consequently, the developed CS/β-GP thermo-sensitive hydrogel system (F8) reveals a promising potential for enhancing the ocular delivery of MOX for treatment of bacterial infections.
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