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Currently, conjunctivitis is treated using ofloxacin eye drop solution, which shows low bioavailability and patient non-compliance. Ofloxacin loaded contact lens can be used to overcome the issues related to eye drop solutions (i.e. low bioavailability and frequent instillation). However, the conventional soaking method shows poor ofloxacin uptake and significantly affect the swelling and optical properties of the contact lenses. The current research investigates the effect of microemulsion on the ofloxacin uptake and its effect on the physical properties of the contact lens along with ofloxacin-release kinetics. In comparison to the conventional soaking method (Of-SM, ofloxacin-packaging solution), the ofloxacin loaded microemulsion-soaked contact lenses (Of-ME) showed improved drug uptake and physical properties of the contact lenses. The in vitro release data of Of-ME contact lenses showed 72–120 h release profile, while Of-SM contact lenses showed 24–60 h. The in vivo drug release data in the tear fluid (New Zealand rabbit's eye) showed high ofloxacin retention in comparison to the eye drop solution. The efficacy study in the rabbit model showed equivalent healing effect with the Of-ME contact lens in comparison to the frequent high dose eye drop therapy. Thus, the study demonstrates the application of microemulsion system to improve the ofloxacin loading capacity in the contact lens along with improvement in the physical properties to treat conjunctivitis. [ABSTRACT FROM AUTHOR]

BACKGROUND: Conventional formulation of levofloxacin is rapidly and completely metabolized after administration. Fortunately, nanoparticle provides a new way to solve this problem. OBJECTIVE: To prepare a levofloxacin-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticle that can reduce administration frequency, maintain a stable and effective plasma concentration, and also can be combined with tissue-engineered scaffold materials. METHODS: Levofloxacin-loaded PLGA nanoparticles were prepared by emulsion solvent evaporation method. Twenty-four rabbits were taken to investigate the effect of nanoparticle formulation on the pharmacokinetics of levofloxacin and randomized into three groups (n=8 per group): general formulation group received an injection of levofloxacin (20 mg/kg) via ear vein; non-loaded nanoparticle group received an injection of blank nanoparticles; and levofloxaxin-loaded nanoparticle group received an injection of the corresponding levofloxacin-loaded nanoparticles. At different times, blood samples were collected to analyze the drug concentration of levofloxaxin. The antimicrobial activity of the levofloxacin-loaded nanoparticle was evaluated based on the rabbit model of Escherichia coli-induced urinary tract infection. Forty-five New Zealand white rabbits were used to establish urinary tract infection models and randomly divided into three groups (n=15 per group). In negative control group, rabbits received only an injection of normal saline via ear vein. In conventional formulation group, rabbits received an injection of levofloxacin (20 mg/kg). In nanoparticle group, rabbits received an injection of the corresponding levofloxacin nanoparticles. Subsequently, blood samples were obtained, and white blood cell (WBC) count and neutrophil percentage was tested; at the same time, the middle segment morning urine was collected to detect bacteriuria and urine WBC positive rates. At 9 days, the histopathologic analysis of the bladder mucosa was done. RESULTS AND CONCLUSION: (1) In vivo the pharmacokinetics: Compared with the conventional formulation group, the ideal levofloxacin-loaded PLGA nanoparticles prepared under optimal conditions significantly reduced the fluctuations in plasma concentration and frequency of administration. (2) Antimicrobial activity: Escherichia coli-induced urinary tract infection was gradually in control in the conventional formulation group and levofloxacin-loaded PLGA nanoparticle group, and basically cured at 9 days after injection. In addition, the number of cured patients was basically higher in the levofloxacin-loaded PLGA nanoparticle group than the conventional formulation group at the same time point, but there was a significant difference between the two groups only at 5 days after treatment. It can be concluded that levofloxacin-PLGA nanoparticles provide a well-sustained delivery system for treatment or prevention of urinary tract infections and provide a foundation for further investigations on tissue-engineered urethral reconstruction. [ABSTRACT FROM AUTHOR]