Ocular penetration of topically applied 1% tigecycline in a rabbit model.

AIM: To evaluate ocular penetration of topically applied 1% tigecycline. METHODS: Forty-two New Zealand White rabbits were divided into 3 groups. A 50 µL drop of 1% tigecycline was administered in group 1. In groups 2 and 3, the drop was administered every 15min for 60min (keratitis protocol). Aqueous humor samples in groups 1 and 2 were collected under general anesthesia at 15, 30, 45, 60, 120, and 180min after the last drop. All animals in group 3 were euthanatized. Cornea, vitreous and blood samples were collected 60 and 120min after the last drop. Tigecycline concentrations were measured using high performance liquid chromatography-mass spectrometry (LC-MS/MS). RESULTS: The peak aqueous humor tigecycline concentration [mean 0.73±0.14 mg/L (SD) and 2.41±0.14 mg/L, respectively] occurred 45min after topical drug application in groups 1 and 2. Group 3 mean values in the cornea, and vitreous, were 3.27±0.50 µg/g, and 0.17±0.10 mg/L at 60min and 3.17±0.77 µg/g and 0.20±0.07 mg/L at 120min, respectively. Tigecycline serum concentrations were negligible. CONCLUSION: Tigecycline levels in the aqueous humor in groups 1 and 2, and in the cornea in group 3 exceeded the minimum inhibitory concentrations of most gram-positive organisms that cause bacterial keratitis and endophthalmitis.

Effect of topical cyclopentolate on post-operative pain after pterygium surgery.

OBJECTIVES: The aim was to evaluate the effectiveness of topical cyclopentolate following pterygium surgery for post-operative ocular pain. METHODS: All participants had nasal pterygium and underwent pterygium excision and conjunctival autografting with fibrin glue. Participants were randomised into two groups. Participants in group 1 received one per cent cyclopentolate eye drops and artificial tears upon completing surgery and were prescribed self-administered drops three times daily for three days, while participants in group 2 received a control (artificial tears) in a manner identical to group 1. Data were gathered regarding post-operative pain intensity experienced during each of the three days. Pain was graded from zero to 10 according to a visual analogue scale, in which zero signified no pain and 10 signified severe, unbearable pain. RESULTS: This study analysed data regarding 38 participants in group 1 and 40 participants in group 2. Results were defined as median with interquartile range (IQR); median of the pain scores at days one, two and three were as follows, respectively: 4 (IQR 2), 2.5 (IQR 1) and 2 (IQR 1.25) for group 1 and 5 (IQR 1), 3 (IQR 1.75) and 3 (IQR 1) for group 2. Pain scores were significantly lower for group 1 compared with group 2 at days one, two and three (p < 0.05). CONCLUSIONS: Topical cyclopentolate seems to be effective and well tolerated following pterygium surgery for post-operative ocular pain.

New therapy option for treatment of methicillin-resistant Staphylococcus aureus keratitis: tigecycline.

PURPOSE: The aim of the present study was to evaluate the effectiveness of topically applied tigecycline for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) in a rabbit model. METHODS: Experimental bacterial keratitis was induced in rabbits by a corneal intrastromal injection of 100 colony-forming units (CFUs) of MRSA bacteria. Sixteen hours after the injection, 28 rabbits were randomly divided into 4 treatment groups of 7 rabbits each. In each group, the rabbits' eyes were treated topically with 19 doses of topical tigecycline (10 or 50 mg/mL), vancomycin (50 mg/mL), or isotonic saline. Slit lamp examinations were performed before and after the inoculation by two observers masked to the study for the determination of clinical severity. Corneas were harvested for bacterial quantitation and histopathologic examination. RESULTS: No significant differences were observed in the clinical scores between pretreatment and posttreatment in the 4 groups (P>0.05). The mean difference between the pretreatment and posttreatment clinical scores from the 4 treatment groups was also not significant (P>0.05). All treatment groups had significantly lower CFUs compared with the control group. There were no significant differences in the bacterial load among the treatment groups. The minimum inhibitory concentration (MIC) for tigecycline was 0.12 µg/mL, whereas the MIC for vancomycin was 2.2 µg/mL. The tigecycline 10 mg/mL group had the lowest mean epithelial erosion values among the treatment groups. CONCLUSIONS: Topical tigecycline significantly reduced the bacterial load in infected rabbit corneas and may be as effective as vancomycin for the topical treatment of MRSA keratitis.

Antiangiogenic effect of itraconazole on corneal neovascularization: a pilot experimental investigation.

PURPOSE: To investigate the antiangiogenic effect of itraconazole for the prevention of experimentally induced corneal neovascularization and whether the efficacy depends on the route of administration. MATERIALS AND METHODS: Thirty-six rats were randomly divided into 6 groups with 6 rats in each group. Chemical cauterization of the cornea was performed using silver nitrate/potassium nitrate sticks, and the rats were subsequently treated daily with topical (10 mg/ml), subconjunctival (10 mg/ml) or intraperitoneal (19 mg/kg) itraconazole for 7 days. Control rats received topical, subconjunctival or intraperitoneal 0.9% saline. On the 8th day of the experiment, the rat corneas were photographed to determine the percentage area of the cornea covered by neovascularization. The maximum density of corneal neovascularization was determined by microscopy. RESULTS: The median percentage of corneal neovascularization for group 1 was 31.5% (95% confidence interval, 27.5-35.5%); in group 3, it was 32% (23.5-39.8%); in group 5, it was 47% (36.3-60.0%). The percentages of corneal neovascularization in groups 2, 4 and 6 (the control groups) were 70% (95% confidence interval, 60.7-77.3%), 69% (63.0-77.7%) and 68% (56.5-78.5%), respectively. The area of neovascularization was smaller after itraconazole treatment as compared to saline treatment. Further, the area of neovascularization was smaller after topical and subconjunctival administration than after intraperitoneal administration. Histological evaluation of the corneas showed the most extensive corneal neovascularization in the control group. No local or systemic adverse effects were seen from either treatment group. CONCLUSION: Itraconazole reduces corneal neovascularization shortly after chemical burn. However, a larger experimental study is necessary to confirm the data of this investigation.

Inhibition of corneal neovascularization by topical and subconjunctival tigecycline.

Objective. To investigate the effects of topical and subconjunctival tigecycline on the prevention of corneal neovascularization. Materials and Methods. Following chemical burn, thirty-two rats were treated daily with topical instillation of 1 mg/mL tigecycline (group 1) or subconjunctival instillation of 1 mg/mL tigecycline (group 3) for 7 days. Control rats received topical (group 2) or subconjunctival (group 4) 0.9% saline. Digital photographs of the cornea were taken on the eighth day after treatment and analyzed to determine the percentage area of the cornea covered by neovascularization. Corneal sections were analyzed histopathologically. Results. The median percentages of corneal neovascularization in groups 1 and 3 were 48% (95% confidence interval (CI), 44.2-55.8%) and 33.5% (95% CI, 26.6-39.2%), respectively. The median percentages of corneal neovascularization of groups 1 and 3 were significantly lower than that of the control group (P = 0.03 and P < 0.001, resp.). Histologic examination of samples from groups 1 and 3 showed lower vascularity than that of control groups. Conclusion. Topical and subconjunctival administration of tigecycline seems to be showing promising therapeutic effects on the prevention of corneal neovascularization. Furthermore, subconjunctival administration of tigecycline is more potent than topical administration in the inhibition of corneal neovascularization.

Choroidal thinning in pseudoexfoliation syndrome detected by enhanced depth imaging optical coherence tomography.

PURPOSE: To measure choroidal thickness in patients with pseudoexfoliation (PEX) syndrome and to compare the values with control eyes using enhanced depth imaging optical coherence tomography (EDI-OCT). METHODS: Thirty-four patients with PEX syndrome and 30 age- and sex-matched healthy subjects were included in this study. Only one eye of each of the patients was included. Choroidal thickness was measured manually from the outer border of the retinal pigment epithelium to the inner scleral border at the subfovea, 3 mm temporal to the fovea, and 3 mm nasal to the fovea using EDI-OCT. RESULTS: A total of 34 eyes from 34 consecutive patients with PEX syndrome (19 women and 15 men; mean age 75.3 ± 6.6 years) were included in the analysis. The mean subfoveal, temporal, and nasal choroidal thickness was significantly thinner in the PEX syndrome group compared with the control group (p<0.05, at all points). The mean choroidal thickness in the PEX syndrome group was as follows: 259 ± 33 µm, 211 ± 29 µm, and 106 ± 24 µm, subfoveal, temporal, and nasal to the fovea, respectively. In comparison, the mean choroidal thickness in the control group was 274 ± 23 µm, 225 ± 17 µm, and 117 ± 17 µm, at the subfovea, 3 mm temporal to the fovea, and nasal to the fovea, respectively. CONCLUSIONS: In PEX syndrome, there is choroidal thinning subfoveal, temporal, and nasal to the fovea on EDI-OCT. Decreased choroidal thickness, probably due to increased vascular resistance, and reduced blood flow, is seen in PEX syndrome.