Development and optimization of ocular in situ gels loaded with ciprofloxacin cubic liquid crystalline nanoparticles

Ciprofloxacin (Cf) is antibiotic used oculary for treatment of conjunctivitis and corneal ulcers. The barriers for its use are: high dosage frequency and poor solubility lead to ocular irritation. This study sought to develop ciprofloxacin-cubosomal (Cf-Cub) in situ gel in order to improve eye permeation, prolong the ocular retention time, and enhance its antimicrobial activity. Box-Behnken design was used to prepare cubosomes. Three independent variables were; Phytantriol amount, Lutrol amount, and hydration media pH, while particle size, encapsulation, and steady state flux were evaluated as dependent variables. The optimised cubosomes were evaluated for antimicrobial activity, and in vivo estimation of Cf in the aqueous humour of rabbits' eyes. The results indicated that, the optimised formula consisted of 60 mg of Cf, 100 mg phytantriol, 25 mg Lutrol, and hydration media pH equal 5.8 produced cubosomes with 121 nm size, 75% entrapment, and 2.54 times antimicrobial activity compared with commercially eye drops. The estimation of Cf in aqueous humour indicated that once daily administration of the optimised formula maintain the drug concentration above MIC compared with commercial drops which require four times daily administration. This confirmed that optimised formula improved eye permeation, prolonged the ocular retention time, and enhanced the antimicrobial activity.