Intracameral and lenticular penetration of locally applied deuterium-labeled vitamin E in rats

PURPOSE: To confirm the intraocular dynamics of 1% deuterium (D)-labeled alpha-tocopherol acetate (VEA) solution. METHODS: The concentrations of D3-VEA and D3-alpha-tocopherol (VE) derived from D3-VEA in the aqueous humor and lens were measured after instilling 1% D3-VEA continuously into the cul-de-sac of rat eyes for one and three weeks. D3-VEA and D3-VE concentrations were determined by gas chromatograph/mass spectrometry. RESULTS: D3-VEA and D3-VE concentrations in the aqueous humor after one and three weeks of continuous administration were 93.1 and 498.9, and 9.4 and 21.5 ng/ml, respectively. The concentrations in the lens were 15.0 and 6.1, and 9.8 and 4.8 ng/g, respectively. CONCLUSION: The penetration of VEA into the aqueous humor and lens by eyedrop application was confirmed.     

Intracameral and Lenticular Penetration of Locally Applied Deuterium-Labeled Vitamin E in Rats

Purpose: To confirm the intraocular dynamics of 1% deuterium (D) labeled alpha-tocopheral acetate (VEA) solution.Methods: The concentrations of D(3)-VEA and D(3)-alpha-tocopherol (VE) derived from D(3)-VEA in the aqueous humor and lens were measured after instilling 1% D(3)-VEA continuously into the cul-de-sac of rat eyes for one and three weeks. D(3)-VEA and D(3)-VE concentrations were determined by gas chromatograph/mass spectrometry.Results: D(3)-VEA and D(3)-VE concentrations in the aqueous humor after one and three weeks of continuous administration were 93.1 and 498.9, and 9.4 and 21.5 ng/mL, respectively. The concentrations in the lens were 15.0 and 6.1, and 9.8 and 4.8 ng/g, respectively.Conclusion: The penetration of VEA into the aqueous humor and lens by eyedrop application was confirmed.     

人眼滴用氧氟沙星和环丙沙星及妥布霉素的前房穿透性研究

目的 比较人眼滴用氧氟沙星、环丙沙星及妥布霉素的前房穿透性差异。方法 2003年4～8月在我院门诊预行白内障超声乳化术的老年白内障患者125例(125只单侧眼),使用随机数字表分为3个大组：氧氟沙星组(42只眼),环丙沙星组(41只眼),妥布霉素组(42只眼),每个大组再使用随机排列表分为5个小组,每个小组8或9只眼。按不同大组,术前局部给予0．3％氧氟沙星、0．3％环丙沙星或0．3％妥布霉素,滴眼6次,每次间隔15min。手术时按不同小组,于最后1次给药后7．5、15．0、30．0、60．0、120．0min时抽取前房水约100μl。使用高效液相色谱仪分析前房水中药物浓度。结果 各时间点前房内氧氟沙星浓度均明显高于环丙沙星,氧氟沙星生物利用度是环丙沙星的6倍。高效液相色谱仪未能检测到妥布霉素,故其浓度低于最低检测限0．05μg／ml。结论 人眼滴用氧氟沙星、环丙沙星和妥布霉素的结果表明氧氟沙星前房穿透性最好,提示可作为预防和治疗眼内炎的首选局部用药。     

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.     

Corneal penetration of simultaneously applied topical levofloxacin, norfloxacin and lomefloxacin in human eyes

PURPOSE: This study was performed to assess the corneal penetration of three topically applied fluoroquinolones (levofloxacin, norfloxacin and lomefloxacin) in corneal buttons obtained from patients undergoing penetrating keratoplasty. METHODS: Fourteen patients received three drops each of 0.5% levofloxacin, 0.3% norfloxacin and 0.3% lomefloxacin (the standard clinically available preparations) over a 30-min interval beginning 90 mins before their scheduled keratoplasty. Corneal samples obtained from excised buttons at the time of surgery were stored at - 80 degrees until analysis. The concentration of the administered fluoroquinolones was measured using high-performance liquid chromatography. RESULTS: The mean corneal concentration of levofloxacin (4.6 +/- 3.5 microg/g, mean +/- standard deviation) was significantly higher than that of lomefloxacin (2.7 +/- 1.8 microg/g, p = 0.0018) and norfloxacin (1.3 +/- 1.2 microg/g, p = 0.00012). CONCLUSION: Levofloxacin achieves a higher mean corneal concentration than norfloxacin and lomefloxacin in the human cornea.     

Physical properties of vitamin E oil and silicone oil

A comparison of the physical properties of vitamin E oil and silicone oil is made. The parameters measured include: viscosity, fluid density, refractive index and wetting characteristics of the water/liquid interface. These properties showed remarkable similarities between vitamin E oil and silicone oil.     

Vitamin E and retrolental fibroplasia. Improved visual outcome with early vitamin E

In an attempt to determine the role of vitamin E in retrolental fibroplasias (RLF), experience with 174 infants of less than 1500 g, all of whom survived beyond four weeks of age, the time of the initial eye examination, is reported. In Phase I, a prospective randomized controlled trial of parenteral vitamin E, 48 infants received intramuscular vitamin E and 6.3% had evidence of cicatricial RLF at follow-up, compared to 51 controls of whom 10% had cicatricial RLF. In Phase II, a nonrandomized prospective experience with the administration of oral vitamin E, 44 infants received early (<12 hours of age) vitamin E and none developed cicatricial RLF, eight received oral vitamin E after 39 hours of age (mean age 167.5 hours) and 38% developed cicatricial RLF, and 23 received no vitamin E and 17% had evidence of cicatricial RLF. Overall, 8.6% of the infants studied had cicatricial RLF at follow-up, and four infants (2.3%) were blind, none of these four having received vitamin E. The incidence of cicatricial RLF at follow-up was significantly lower for infants who received early parenteral and oral vitamin E compared with those who did not (3 of 92 vs 12 of 82, χ² = 5.75, P = 0.017), as was the incidence of Grade III or greater cicatrix (0 of 92 vs 7 of 82, χ² with Yates = 6.12, P = 0.013). Stepwise multiple linear regression analysis revealed that two factors distinguished infants who developed cicatricial RLF from those who did not; the lack of early vitamin E (P = 0.0000), and the number of days of exposure to supplemental oxygen (P = 0.002). It is recommended that vitamin E be given within 12 hours of birth to all infants less than 1250 g who require supplemental oxygen.     

雷帕霉素滴眼液对碱烧伤角膜新生血管的影响

目的探讨雷帕霉素（Rapamycin）滴眼液对兔碱烧伤后角膜新生血管的抑制作用。方法48只新西兰白兔右眼碱烧伤制成新生血管模型,随机分成A组（0．1％雷帕霉素滴眼液组）,B组（0．5％雷帕霉素滴眼液组）,C组（1％雷帕霉素滴眼液组）,D组（赋形剂对照组）。烧伤后每天滴眼4次。观测角膜浑浊、融解情况和新生血管生长并测量长度。角膜组织HE染色观察病理改变,炎性细胞计数,免疫组化检测角膜内皮生长因子（VEGF）的表达。结果碱烧伤后各组角膜均出现不同程度的角膜浑浊、融解,随时间延长,对照组角膜浑浊、融解明显,角膜基质内大量炎性细胞浸润和粗大新生血管形成。治疗组的角膜浑浊、融解减轻,伤后7d、14dB、C组炎症细胞计数、角膜新生血管面积及VEGF表达均小于对照组（P〈0．05）。各组角膜新生血管面积与角膜炎性细胞数及VEGF表达呈正相关。结论0．5％及1％雷帕霉素滴眼液可有效抑制碱烧伤引起的角膜免疫炎症反应,抑制角膜新生血管的生长,为眼碱烧伤后角膜新生血管的治疗提供了新的选择。     

Effects of vitamin E and pinoline on retinal lipid peroxidation

Background: Pinoline is a pineal indoleamine naturally found in the retina. This study compared the effects of pinoline and vitamin E on the copper (I)‐induced retinal lipid peroxidation (LPO). Methods: Porcine retinal homogenates were mixed with 120 μM copper (I) solution. The mixtures were co‐incubated with various concentrations of pinoline or trolox (watersoluble vitamin E analogue) at 37 degrees Centigrade for 60 minutes. The amounts of malondialdehyde (MDA) and protein were assayed to quantify the LPO. Results: Copper (I) ions significantly increased the MDA concentration in the retinal homogenates (p < 0.0007). Both pinoline and trolox significantly suppressed MDA in a dose‐dependent manner (p < 0.0001) and their effects were significantly different (p = 0.004). The concentrations that inhibited 50 per cent of LPO were 0.24 mM and 0.68 mM for pinoline and trolox, respectively. Discussion: Pinoline suppressed the LPO at a potency of 2.8 times compared with trolox. The results support an anti‐oxidative role for pinoline in the retina. Further study is required to characterise the pharmacological potency of pinoline in vivo.