Disposable 1-day Acuvue contact lenses for the delivery of lomefloxacin to rabbits' eyes.

PURPOSE: To investigate the ability of a disposable soft contact lens (1-Day Acuvue) to deliver lomefloxacin, a fluoroquinolones antibiotic, into the cornea and aqueous humor of rabbits. METHODS: Experiments were conducted on adult albino rabbits. 1-Day Acuvue lenses were immersed for 1 hour in commercially-available lomefloxacin eye solution and then placed on the cornea. After 0.5, 2, 4,6, and 8 hours, the animals were killed and the lenses were removed and placed into a 20 mL saline bath. Corneal tissue and aqueous humor samples were also obtained at these times. The release of lomefloxacin from the lenses was calculated by measuring the amount of drug remaining in the lenses after removal from the rabbit eyes. The concentration of lomefloxacin in the cornea and anterior chamber following the wearing of lomefloxacin-loaded lenses was compared with the concentrations following frequent-drop therapy (one drop of lomefloxacin hourly for 8 hours). RESULTS: In vivo, lomefloxacin was released from 1-Day Acuvue lenses gradually over 8 hours. The cornea and aqueous humor levels in the eyes following the wear of lomefloxacin-loaded lenses were significantly higher than those achieved by frequent-drop therapy. The drug levels in the cornea and aqueous humor generally remained above the 90% minimal inhibitory concentration for 8 hours in the 1-Day Acuvue lens group. CONCLUSIONS: 1-Day Acuvue contact lenses soaked in 0.3% lomefloxacin can release sufficient amounts of lomefloxacin and in this study produced higher levels in both the cornea and aqueous humor than that achieved by frequent-drop therapy for up to 8 hours. We conclude that 1-Day Acuvue contact lens can be used as a drug delivery system for lomefloxacin.

Studies on the uptake and release of fluoroquinolones by disposable contact lenses.

PURPOSE: To evaluate the ability of three types of disposable contact lenses to take up and release three kinds of fluoroquinolones in vitro. METHODS: We evaluated three FDA-approved disposable soft contact lenses (1-Day Acuvue, Medalist, and 14UV) for their ability to absorb and release three kinds of fluoroquinolones. Contact lenses were presoaked in fluoroquinolones for 1, 4, and 24 hours, and the uptake was determined by measuring the concentration of fluoroquinolones in the three types of disposable soft contact lenses by high pressure liquid chromatography (HPLC). After uptake, the lenses were placed in fresh saline baths, and release rates from the lenses were determined by measuring the concentration of fluoroquinolones in the saline baths by HPLC. RESULTS: The disposable soft contact lens with the highest uptake of fluoroquinolones was the 1-Day Acuvue. After presoaking, drug concentrations in the 1-Day Acuvue and Medalist were higher than their theoretical saturation concentrations (i.e., the concentration of the fluoroquinolone eye drops [0.3%]). The release rates from the 1-Day Acuvue and Medalist lenses were slower than for the 14 UV lens. CONCLUSIONS: These results indicate that among the lenses tested, the most practical drug delivery system is the 1-Day Acuvue disposable soft contact lens.

[Endogenous substance P in corneal epithelial cells and keratocytes].

PURPOSE: To detect endogenous substance P(SP) and neurokinin receptor 1(NK1R) in cultured human epithelial cells of the cornea(HE) and human keratocytes(HK). METHOD: Messenger RNA(mRNA) expression of SP and endogenous SP in HE and HK were detected by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). mRNA expression of NK1R in HE and HK was detected by RT-PCR. RESULTS: The mRNA expression of SP and endogenous SP were recognized in HE and HK. The mRNA of NK1R was also expressed in HE and HK. CONCLUSION: It appears that endogenous SP regulates the biological functions of HE and HK in an autocrine or paracrine fashion.

Oral mucosal bioadhesive tablets of pectin and HPMC: in vitro and in vivo evaluation.

The potential of tablets containing 1:4, 1:1 and 4:1 weight ratios of pectin and hydroxypropyl methylcellulose (HPMC) for the sustained release of diltiazem by sublingual administration has been investigated. Measurements of maximum adhesive force to rat peritoneal membrane indicated a satisfactory bioadhesive strength. An in vitro sustained release of diltiazem over 5 h was achieved with bilayer tablets composed of a drug-free ethylcellulose layer in addition to the pectin/HPMC layer containing drug. Plasma concentration-time curves obtained following sublingual administration to rabbits of single and bilayer tablets with 1:1 weight ratios of pectin and HPMC showed evidence of sustained release of diltiazem. Bioavailability of diltiazem was 2.5 times that achieved by oral administration for single layer tablets and 1.8 times for the bilayered tablets.