Penetration Pharmacokinetics of Topically Administered 0.5% Moxifloxacin Ophthalmic Solution in Human Aqueous and Vitreous

AIE-Active Antibiotic Photosensitizer with Enhanced Fluorescence in Bacteria Infected Cells and Better Therapy Effect toward Drug-Resistant Bacteria

It is well-known that bacterial infections will induce a variety of diseases in the clinic. In particular, the emergence of drug-resistant bacteria has increased the threat to human health. The development of multiple modes of therapy will effectively fight against drug-resistant bacterial infections. In this work, we covalently attached an AIE photosensitizer to the antibiotic of moxifloxacin hydrochloride (MXF-HCl) and synthesized an antibiotic derivative, MXF-R, with pharmacological activity and photodynamic activation. In infected cells, MXF-R showed enhanced fluorescence after it specifically binds to bacteria; thus, in situ visualization of the bacteria was realized. Notably, through chemo- and photodynamic therapy, MXF-R exhibited better antibacterial activity than its parent antibiotic in rapid sterilization, and it achieved effective killing for moxifloxacin resistant bacteria. In addition, MXF-R shows a broad-spectrum antibacterial effect and could be used in the recovery therapy of infected wounds in mice, demonstrative of a significant therapeutic effect and good biological safety. Thus, as a promising multifunctional antibacterial agent, MXF-R will have tremendous potential in in situ visualization study and killing of drug-resistant bacteria. This work provides an innovative strategy for solving critical disease through the combination of materials and biomedical sciences.

Cataract Surgery by Intraoperative Surface Irrigation with 0.25% Povidone-Iodine

Postoperative endophthalmitis after cataract surgery is typically caused by the patient's own conjunctival normal bacterial flora. A three-step approach is recommended to prevent endophthalmitis: (1) "border control" to prevent microorganisms from entering the eye by disinfecting the ocular surface is the most important measure; (2) bacteria that have gained access into the anterior chamber are reduced by irrigation; (3) bacteria remaining in the anterior chamber and vitreous at the end of surgery are controlled by antibacterial drugs. We have devised a method, "the Shimada technique", for irrigating the ocular surface with povidone-iodine, a disinfectant with potent microbicidal effect and established effective and safe concentrations for eye tissues. Povidone-iodine exhibits a bactericidal effect for a wide concentration range of 0.005-10%, but 0.1% povidone-iodine has the highest activity and requires the shortest time of only 15 s to achieve microbicidal effect. When used to irrigate the ocular surface every 20-30 s during cataract surgery, 0.25% povidone-iodine is conceivably diluted to around 0.1%. Irrigation with 0.25% povidone-iodine during cataract surgery significantly reduced bacteria contamination rate in the anterior chamber compared with saline (p = 0.0017) without causing corneal endothelial damage.

Incremental effect of topical and oral moxifloxacin administration with surgical intracameral prophylaxis

OBJECTIVE

To determine how supplemental perioperative topical or oral moxifloxacin administration impacts anterior chamber (AC) antibiotic concentrations beyond those achieved by intracameral (IC) administration alone for postoperative endophthalmitis (POE) prophylaxis.

DESIGN

Mathematical modeling.

METHODS

The mathematical model developed by Arshinoff, Modabber, and Felfeli was adapted to calculate all reported data. A literature review of pharmacokinetic data for topical and oral moxifloxacin was used to inform the expansion of the model.

RESULTS

Our previously constructed IC model yields a dose of moxifloxacin in the AC sufficient to confer bactericidal coverage against the most common POE pathogen, methicillin-sensitive Staphylococcus aureus (MSSA), for ∼40 hours postoperatively. Topical 0.5% moxifloxacin eye drops alone, administered every 4 or 6 hours, achieve an AC concentration just above or at the mutant prevention concentration (MPC) for MSSA, respectively, whereas 8-hour dosing produces levels generally below the MPC. Combining topical moxifloxacin with IC increases the AC concentration above IC alone only after 20 or more hours and maintains the AC concentration at, or just below, the MPC for MSSA for as long as the drops are continued. Combined perioperative oral moxifloxacin with IC increases AC levels over IC alone only after 16 hours and maintains the AC concentration above the MPC for MSSA for an additional 5 hours, owing to the systemic reservoir.

CONCLUSIONS

The addition of topical or oral moxifloxacin supplemental to IC can extend the duration of bactericidal coverage for the most common, but not the most resistant POE-causing pathogens.

Effect of Topical Antibiotic Prophylaxis on Conjunctival Flora and Antibiotic Resistance Following Intravitreal Injections in Patients with Type 2 Diabetes

Purpose

We sought to determine changes in the conjunctival bacterial flora and antibiotic resistance after topical antibiotic drops for infection prophylaxis were administered following intravitreal injections in patients with type 2 diabetes.

Methods

This prospective and nonrandomized cohort study included 116 eyes of 116 treatment-naive patients with type 2 diabetes who received six serial intravitreal anti-vascular endothelial growth factor injections for macular edema. Three conjunctival cultures were obtained from each eye over the course of the study (Culture 1, baseline; Culture 2, 1 month after the third injection; and Culture 3, 1 month after the sixth injection). The study subjects were given topical moxifloxacin hydrochloride for 4 days after each monthly intravitreal injection. The growth patterns of conjunctival bacterial flora and the antibiotic resistance to several commonly used antibiotics were examined.

Results

The rate of culture positivity increased significantly during the observation period (Culture 1, n = 47, 40.5%; Culture 2, n = 58, 50%; Culture 3, n = 76, 65.5%, p < 0.001). The bacterium with the highest baseline culture positivity was Staphylococcus epidermidis (n = 45, 38.8%), which increased significantly during the observation period (p < 0.001). No significant increase was noted in the culture positivity of the other bacteria with baseline culture positivity (p > 0.05). Regarding antibiotic susceptibility, significant increases in resistance to the fluoroquinolone group of drugs were noted (p < 0.001). No significant changes in sensitivity were detected in the other 11 investigated antibiotics that are commonly used in clinical practice (p > 0.05).

Conclusions

The use of topical moxifloxacin after each intravitreal injection significantly increases the fluoroquinolone resistance of the ocular surface flora and the culture-positivity rate of S. epidermidis in patients with type 2 diabetes.

The Role of Systemic Antimicrobials in the Treatment of Endophthalmitis: A Review and an International Perspective

Background

The optimal management of patients with endophthalmitis is challenging and includes both intravitreal and, in some cases, systemic antimicrobials. Systemic antimicrobials may be administered either intravenously or orally. In this article we review systemic antimicrobial options currently available for the treatment of types of endophthalmitis and the role of systemic antimicrobials (antibiotics and antifungals) in these treatments.

Review

While systemic antimicrobials are not universally utilized in the management of endophthalmitis, they may be helpful in some circumstances. The blood–retinal barrier affects the penetration of systemic medications into the posterior segment of the eye differently; for example, moxifloxacin and imipenem cross the blood–retinal barrier relatively easily while vancomycin and amikacin do not. However, inflammation, including endophthalmitis, may disrupt the blood–retinal barrier, enhancing the penetration of systemic agents into the eye.

Conclusion

Systemic antimicrobials may be particularly beneficial in patients with certain types of endophthalmitis; as such, they are standard treatment in the management of endogenous endophthalmitis (fungal and bacterial) and also widely used for prophylaxis and treatment of open-globe injuries. Although systemic antimicrobials are used in some patients with acute-onset postoperative endophthalmitis following cataract surgery, the literature generally does not support this practice. It is noted that there are currently no randomized clinical trials demonstrating a benefit of systemic antibiotics for any category of endophthalmitis.

Conjunctival bacterial flora and antimicrobial susceptibility in bacterial pathogens isolated prior to cataract surgery

PURPOSE

To optimize prophylactic antibiotic administration, antibiotic susceptibility before cataract surgery was investigated using ocular bacteria isolated preoperatively.

DESIGN

Retrospective cross-sectional study.

METHODS

In 204 eyes of 102 patients who underwent routine bilateral cataract surgery, conjunctival sac scrapings were collected 1-2 weeks before surgery. A total of 192 major pathogens among the 470 isolated bacteria were subjected to susceptibility testing. The major pathogens included Staphylococcus aureus, Staphylococcus epidermidis, coagulase-negative staphylococci (CNS) other than S. epidermidis, Enterococcus faecalis, and Streptococcus spp. The following antibiotics were tested: cefmenoxime (CMX), ceftazidime (CAZ), tobramycin (TOB), vancomycin (VAN), erythromycin (EM), moxifloxacin (MFLX), gatifloxacin (GFLX), levofloxacin (LVFX), chloramphenicol (CP), and imipenem (IP).

RESULTS

The proportions of isolates with minimum inhibitory concentration (MIC) of S. epidermidis (N = 82), exceeding 4 μg/ml were high for CAZ (95.1%), EM (32.9%), LVFX (39.0%), and CP (82.9%). Susceptible (S) proportion was high for CMX (98.8%), VAN (100%), CP (93.9%), and IP (97.6%) but relatively low for MFLX (59.8%), GFLX (54.9%), and LVFX (54.9%). The MIC₉₀ values were high for CMX (16 μg/ml), CAZ (64 μg/ml), TOB (32 μg/ml), EM (128 μg/ml), LVFX (16 μg/ml), and CP (8 μg/ml). The MIC of quinolonesof pathogenic bacteria other than S.epidermidis (N = 108), exceeded 4 μg/ml for 11 isolates, including two Methicillin-resistant Staphylococcus aureus.

CONCLUSIONS

The increase in resistance of resident bacteria present in the conjunctival sac to antibiotics indicates that systemic and topical antibiotics are no longer effective, especially against external organisms affecting the eye.

Management of Endophthalmitis with and without Topical Antibiotics: A Case-Control Study

PURPOSE

The aim of this study was to compare the management outcome of endophthalmitis with and without the use of topical antibiotics.

METHODS

A retrospective comparative chart review of 2 cohorts of endophthalmitis (other than those associated with open-globe injury, keratitis, or wound site infection), one managed with topical antibiotics (TA group) and one without (NTA group), was performed.

RESULTS

The study included a total of 270 eyes of 270 patients. Of these, 169 eyes were in the TA group and 101 were in the NTA group. Post-cataract surgery was the most common etiology, accounting for 81.06 and 78.2% of cases, respectively (p = 0.57). A favorable functional outcome at the last visit was seen in 37.5 and 39.6% of eyes (p = 0.73), and a favorable anatomic outcome was noted in 61.2 and 49.5% of eyes (p = 0.06), respectively. The median follow-up was 3.5 and 9 months, respectively (p < 0.0001). Susceptibilities to the common antibiotics used (vancomycin, ceftazidime, and amikacin) were comparable, with the exception of imipenem, for which the susceptibility noted was 95 and 66%, respectively (p = 0.01). Culture positivity in the TA group was seen in 72 out of 169 eyes (42.6%), while in the NTA group it was seen in 98 out of 101 eyes (97.02%; p < 0.0001).

CONCLUSION

Topical antibiotics do not give any added advantage in the management of endophthalmitis otherwise being treated with intravitreal antibiotics and standard vitrectomy techniques.

Complications of intravitreal injections in patients with diabetes

Intravitreal injections for the treatment of retinal disorders and intraocular infection have become a common ophthalmic procedure, and injections of anti-vascular endothelial growth factor agents or steroids are frequently performed for the treatment of diabetic macular edema or other diabetic vascular pathology. Diabetic patients may be at higher risk of adverse events than non-diabetic individuals given frequent systemic co-morbidities, such as cardiovascular and renal disease, susceptibility to infection, and unique ocular pathology that includes fibrovascular proliferation. Fortunately, many associated complications, including endophthalmitis, are related to the injection procedure and can therefore be circumvented by careful attention to injection techniques. This review highlights the safety profile of intravitreal injections in patients with diabetes. Although diabetic patients may theoretically be at higher risk than non-diabetic patients for complications, a comprehensive review of the literature does not demonstrate substantial increased risk of intravitreal injections in patients with diabetes.

The effect of prophylactic topical antibiotics on bacterial resistance patterns in endophthalmitis following intravitreal injection

PURPOSE

The purpose of this study was to evaluate the effect of prophylactic topical antibiotics on bacterial resistance patterns in endophthalmitis following intravitreal injection of anti-vascular endothelial growth factor (VEGF) medications.

METHODS

In this retrospective case-control study, billing records and an infection log were used to identify all cases of endophthalmitis following intravitreal injection of ranibizumab, bevacizumab, or aflibercept between January 1, 2009 and September 30, 2013 at a single retina practice. A 28-month period when topical antibiotic drops were prescribed for use four times a day for 4 days following intravitreal injection was compared to a 21-month period when topical antibiotics were not prescribed. Patients treated during an 8-month transition period were excluded as prescription practices were changed.

RESULTS

During the study period, a total of 172,096 anti-VEGF injections were performed. During the period when antibiotics were prescribed, 28 cases of suspected infectious endophthalmitis occurred from a total of 57,654 injections, ten of which were culture-positive. During the period when antibiotics were not used, 24 cases of suspected endophthalmitis occurred from a total of 89,825 injections, six of which were culture-positive. During the antibiotic period, four of the ten (40 %) culture-positive cases grew bacteria resistant to the prescribed prophylactic antibiotics. In contrast, none of the six culture-positive cases grew bacteria resistant to those antibiotics during the period when antibiotics were not used (odds ratio = 9.0; 95 % confidence interval = 0.40-203.3; p = 0.17).

CONCLUSIONS

The use of prophylactic topical antibiotics following intravitreal injection may lead to higher rates of antibiotic-resistant bacteria in culture-positive endophthalmitis cases.

Oral fluoroquinolones and risk of glaucoma

OBJECTIVE

To evaluate the risk of developing glaucoma in patients taking systemic fluoroquinolones.

METHODS

A case-control study was carried out among a cohort of subjects who had visited an ophthalmologist in the Province of British Columbia, Canada from 2000 to 2007. Cases were identified as those newly diagnosed with glaucoma (ICD-9 360). For each case, 5 controls were selected and matched to the cases by age and calendar time. Crude and adjusted rate ratios (RRs) for current, recent, past, and distant use of fluoroquinolones were calculated.

RESULTS

From the cohort of 989,591 subjects, 178,264 subjects were diagnosed with glaucoma and 891,320 were corresponding controls. The 2 groups had same average age of 65 and comparable systemic comorbidities including hypertension, coronary artery disease, and diabetes. There was no statistically significant association between the use of systemic fluoroquinolones and the development of glaucoma for current use [RR=1.01 (95% confidence interval (CI), 0.95-1.07)], recent use [RR=1.00 (95% CI, 0.92-1.08)], or past use [RR=0.94 (95% CI, 0.90-1.00)]. Distant use of systemic fluoroquinolones had a small statistically significant increased risk of developing glaucoma [RR=1.12 (95% CI, 1.09-1.14)].

CONCLUSIONS

There was no detected increased association of the development of glaucoma with current, recent, or past use of systemic fluoroquinolone but a minimal statistically significant increased risk was associated with distant use. Future studies should further examine a potential delayed response with fluoroquinolones and glaucoma.

A Case Report of Severe Corneal Toxicity following 0.5% Topical Moxifloxacin Use

Moxifloxacin is a widely used topical antibiotic in various bacterial infections of the eye. Its safety and efficacy have been proved by many studies. We report a case of a rare adverse effect following its use. A 10-year-old female who had presented with acute bacterial conjunctivitis in both eyes with no corneal involvement was started on preservative-free 0.5% topical moxifloxacin four times a day. The child developed a severe form of corneal toxicity in both eyes with circumcorneal congestion and corneal edema following its use. The child's visual acuity had dropped from 20/20 to 20/400 in both the eyes. Topical moxifloxacin was discontinued, following which the cornea cleared dramatically and the visual acuity became normal. This case indicates that though rare, topical moxifloxacin can cause severe keratitis and that more studies need to be conducted to evaluate its safety.

Safety of prophylactic intracameral moxifloxacin ophthalmic solution after cataract surgery in patients with penetrating keratoplasty

AIM

To determine the safety of prophylactic intracameral moxifloxacin after cataract surgery in patients with penetrating keratoplasty (PKP).

METHODS

In this retrospective study of consecutive patients who had phacoemulsification cataract surgery after PKP, were treated with intracameral moxifloxacin 0.5% ophthalmic solution (0.5 mg/0.1 mL). The main outcome measures were anterior chamber reaction, best corrected visual acuity (BCVA), corneal endothelial cell count (ECC), and central corneal thickness (CCT).

RESULTS

Fifty-five patients were recruited (26 males, 29 females). The mean age was 54.36±4.97y (range 45-64y). All eyes had improved postoperative BCVA. The mean BCVA was 0.25 preoperatively and 0.57 postoperatively, which was statistically significant (P<0.001). One eye had 3+, 7 eyes had 2+, 12 eyes had 1+ and 8 eyes had trace amount of aqueous cells on the first day after surgery. All eyes had no anterior chamber cells at subsequent follow up examinations. Effective phacoemulsification time was 4.33±1.01s. The mean ECC was 2340.20 cells/mm(2) preoperatively and 1948.75 cells/mm(2) 1mo postoperatively (P<0.001). The increase of 21.09 µm in postoperative pachymetry 1mo after surgery was statistically significant (P<0.001).

CONCLUSION

No untoward effects were observed after intracameral injection of moxifloxacin (0.5 mg/0.1 mL) in terms of anterior chamber reaction, CCT, ECC, and visual rehabilitation at the conclusion of cataract surgery in patients with PKP.

Effects of moxifloxacin exposure on the conjunctival flora and antibiotic resistance profile following repeated intravitreal injections

AIM

To evaluate the effects of moxifloxacin exposure on the conjunctival flora and antibiotic resistance profile following repeated intravitreal injections.

METHODS

Seventy-two eyes of 36 patients [36 eyes in control group, 36 eyes in intravitreal injection (IVI) group] were enrolled in the study. All the eyes had at least one IVI and had diabetic macular edema (DME) or age-related macular degeneration (ARMD). Moxifloxacin was prescribed to all the patients four times a day for five days following injection. Conjunctival cultures were obtained from the lower fornix via standardized technique with every possible effort made to minimize contamination from the lids, lashes, or skin. Before the application of any ophthalmic medication, conjunctival cultures were obtained from both eyes using sterile cotton culture. An automated microbiology system was used to identify the growing bacteria and determine antibiotic sensitivity.

RESULTS

The bacterial cultures were isolated from 72 eyes of 36 patients, sixteen of whom patients (44.4%) were male and twenty (55.6%) were female. Average age was 68.4±9.0 (range 50-86). The average number of injections before taking cultures was 3.1+1.0. Forty-eight (66.7%) of 72 eyes had at least one significant organism. There was no bacterial growth in 8 (20.5%) of IVI eyes and in 16 (44.4%) of control eyes (P=0.03). Of the bacteria isolated from culture, 53.8% of coagulase negative staphylococci (CoNS) in IVI eyes and 47.2% CoNS in control eyes. This difference between IVI eyes and control eyes about bacteria isolated from culture was not statistically significant (P=0.2). Eleven of 25 bacteria (44.0%) isolated from IVI eyes and 11 (57.9%) of 19 bacteria isolated from control eyes were resistant to oxacillin. The difference in frequency of moxifloxacine resistance between two groups was not statistically significant (12.0% in IVI eyes and 21.1% in control eyes) (P=0.44). There were no cases of resistance to vancomycin, teicoplanin and linezolid.

CONCLUSION

There was no difference in species of bacteria isolated from cultures, or in the frequency of resistance to antibiotics between eyes that had recurrent IVI followed by moxifloxacin exposure compared with control eyes. However, the number of eyes that had bacterial growth was higher in IVI group than in the control group.

Survey of Japanese ophthalmic surgeons regarding perioperative disinfection and antibiotic prophylaxis in cataract surgery

Purpose

To elucidate Japanese trends for perioperative disinfection and antibiotic selection during cataract surgeries.

Methods

Perioperative iodine use and antibiotic prophylaxis for cataract surgery were surveyed in eight regions in Japan by mail or through interviews from February 1 to March 1, 2014.

Results

We surveyed 572 surgeons, of whom 386 (67%) responded. Most of the surgeons (94%) used iodine compounds before surgery for periocular skin disinfection (povidone–iodine [PI]: 79%; polyvinyl alcohol-iodine [PAI]: 15%) or conjunctival disinfection (85%; PI: 36%; PAI: 49%). Preoperative conjunctival iodine was primarily used as an eye wash (irrigation: 95%) and less often as an eye drop (5%). It was determined that 31% of surgeons waited 30 seconds or more between periocular disinfection and conjunctival disinfection. During surgery, 14% of surgeons used iodine several times, including immediately before intraocular lens insertion, and 7% used the Shimada technique (repeated iodine irrigation). Preoperative antibiotic eye drops were used by 99% of surgeons, and antibiotics were added to the irrigation bottle by 22%. The surgeons reported use of subconjunctival antibiotic injections (23%), antibiotic ointments (79%), and intracameral antibiotics (7%: 22 moxifloxacin; 6 levofloxacin). All surgeons prescribed postoperative eye drops, with 10% initiating the drops on the day of surgery.

Conclusion

Iodine compounds are commonly used preoperatively, but few institutions use iodine compounds intraoperatively, particularly with repeated application. The selection of antibiotic administration and disinfection technique has to be at the surgeon’s discretion. However, intracameral antibiotic and intraoperative iodine compound use are techniques that should be widely recognized.

Safety of intracameral injection of moxifloxacin using total replacement technique (bag and chamber flushing)

PURPOSE

To assess the safety of intracameral injection of moxifloxacin (MFLX) using the total replacement technique [bag and chamber (BC) flushing].

METHODS

The anterior chamber including the area behind the intraocular lens was irrigated and replaced using BC flushing. In Group A, 36 patients received balanced salt solution irrigation in the right eye and intracameral MFLX (150 μg/mL: 33-fold dilution of 0.5% eye drops) in the left eye. In Group B, 33 patients received intracameral MFLX in the right (500 μg/mL: 10-fold dilution) and left eyes (150 μg/mL: 33-fold dilution). Visual acuity, intraocular pressure, corneal endothelial cell density, corneal thickness, and foveal thickness were recorded before and up to 3 months after surgery.

RESULTS

In either group, there were no statistically significant differences between the right and left eyes with respect to visual acuity, intraocular pressure, corneal endothelial cell count, and foveal thickness before and at 3 months after surgery. There was no difference in corneal thickness before and at 3 months after surgery. In patients who received 500 μg/mL MFLX during surgery, central corneal thickness at 1 week after surgery was significantly reduced.

CONCLUSIONS

In the present study, there was no adverse effect associated with intracameral injection of 150-500 μg/mL MFLX. Moreover, our results supported the safety of BC flushing. Thus, BC flushing, which can irrigate the inside of the capsular bag and attain stable antibiotic concentrations, appears to be a favorable technique for intracameral injection of MFLX.

Comparative evaluation of aqueous and plasma concentration of topical moxifloxacin alone and with flurbiprofen in patients of cataract surgery

Objectives:

To determine the aqueous and plasma concentrations of moxifloxacin administered topically alone and with flurbiprofen in patients undergoing cataract surgery.

Materials and Methods:

A total of 50 subjects scheduled for routine cataract surgery were randomly allocated to two groups (n = 25 each). Group-1 patients were treated with topical moxifloxacin alone: One drop 6 times/day for 3 days before surgery and one drop 4 times on the day of surgery: Group-2 patients were treated with topical moxifloxacin as in Group-1 and with topical flurbiprofen: One drop 4 times/day for 3 days before and on the day of surgery. The interval between two drugs was 30 min for last 3 days and 15 min on the day of surgery. Last dose was administered 1 h before aqueous humor and blood sampling for both the groups. The antibiotic concentration in aqueous humor and plasma were determined by using high performance liquid chromatography.

Results:

The mean concentration of moxifloxacin in aqueous humor was 1.71 ± 0.82 mg/ml in Group-1 and 2.39 ± 1.34 mg/ml in Group-2. Concentrations of moxifloxacin in aqueous humor were significantly higher in Group-2 than that of Group-1.

Conclusion:

Flurbiprofen may increase the concentration of moxifloxacin in aqueous humor.

Antiproliferative and cytotoxic properties of moxifloxacin on rat retinal ganglion cells

Abstract Purpose: To evaluate the antiproliferative and cytotoxic properties of moxifloxacin on cultured rat retinal ganglion cells (RGC5).

MATERIALS AND METHODS

Rat retinal ganglion cells were exposed to various concentration of moxifloxacin (5-1500 μg/mL). For antiproliferative properties, the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) test was performed. Cellular cytotoxicity was assessed by using the Live/Dead viability/cytotoxicity assay and analyzed by fluorescence microscopy after 24 and 72 h of incubation, respectively.

RESULTS

Neither cytotoxic nor antiproliferative effect of moxifloxacin was observed below 50 μg/mL on RGC5 cells after 24 and 72 h of incubation. At higher concentrations of moxifloxacin (150 μg/mL, 500 μg/mL, and 1500 μg/mL (p < 0.001)) the number of viable cells and the proliferation rate of RGC5 were significantly reduced.

CONCLUSIONS

These results suggest a dose-dependent cytotoxic and antiproliferative effect of moxifloxacin on RGC5. Therefore, intracameral application of moxifloxacin should be used cautiously in patients with increased risk of retinal ganglion cells damage, particularly in glaucoma patients.

Comparative intraocular penetration of 4 fluoroquinolones after topical instillation

PURPOSE

To compare the intraocular penetration of 4 fluoroquinolone eye drops after topical instillation into rabbit eyes.

METHODS

The tested drugs were levofloxacin 1.5% (LVFX), gatifloxacin 0.3%, moxifloxacin 0.5% (MFLX), and besifloxacin 0.6% (BFLX). Forty-eight New Zealand white rabbits were randomly assigned into 2 groups. For group 1 (40 rabbits, 80 eyes), single instillation was performed, and tissue samples were acquired after 0.5, 1, 2, 4, and 6 hours. For group 2 (8 rabbits, 16 eyes), repeated instillation was performed (4 times, every 15 minutes), and tissues were acquired 1 hour after the fourth instillation. The drug concentrations in ocular tissues (cornea, aqueous, conjunctiva, and trisected vitreous) were analyzed with high-performance liquid chromatography.

RESULTS

The AUC 0-6 h (area under the curve, in microgram.hour/gram) in group 1 and the mean concentration (in micrograms/gram) in group 2 for LVFX, gatifloxacin 0.3%, MFLX, and BFLX, respectively, were 22.97, 6.44, 13.54, and 3.29 and 22.60, 6.99, 13.69, and 1.91 in cornea; 5.66, 1.43, 3.38, and 0.42 and 5.52, 1.29, 2.47, and 0.19 in aqueous humor; 2.33, 0.91, 2.17, and 9.83 and 4.51, 0.78, 1.48, and 2.09 in bulbar conjunctiva; 0.243, 0.051, 0.134, and 0.018 and 0.182, 0.055, 0.122, and 0.015 in anterior vitreous; none of the drugs achieved enough concentration in equatorial and posterior vitreous. Repeated instillation resulted in approximately 2.1 times greater penetration than single instillation.

CONCLUSIONS

LVFX and MFLX demonstrated good intraocular penetration particularly in cornea, aqueous humor, and anterior vitreous, and they may be considered the penetrative fluoroquinolones. BFLX showed high concentration in bulbar conjunctiva and may be considered the retentive fluoroquinolone.

The impact of short-term topical gatifloxacin and moxifloxacin on bacterial injection after hypodermic needle passage through human conjunctiva

PURPOSE

To determine the bacterial contamination rate of a 27-gauge needle bore during conjunctival penetration in donor eye bank eyes and the effect of short-term use of topical 0.3% gatifloxacin and 0.5% moxifloxacin.

METHODS

One hundred consecutive human donors had 10 conjunctival penetrations per 10 syringes per eye before antibiotic placement; this was repeated 15 min after antibiotic use. Samples were cultured by expressing 0.3 mL of saline through the needle. Positive cultures were speciated.

RESULTS

There were 1,033 positive cultures (25.8% of all cultures); 568 (28.4%) pre-antibiotics, 249 (24.9%) after gatifloxacin (P=0.04, compared to the pre-antibiotic rate), and 216 (21.6%) after moxifloxacin (P<0.001). The most common organism was Staphylococcus epidermidis [334 positive cultures (8.4%)]. No antibiotic effect was seen on this or other organisms except S. aureus [4.6% pre-antibiotic, 2.8% after gatifloxacin (P=0.02), and 1.8% after moxifloxacin (P<0.001)] and other Staphylococcus species [5.3% pre-antibiotic, 3.6% after gatifloxacin (P=0.04), and 3.2% after moxifloxacin (P=0.01)].

CONCLUSIONS

Transconjunctival penetration often results in needle bore contamination; bacteria are included in an injected solution. Fifteen minutes of exposure to 2 topical antibiotics had a minimal effect on bacterial contamination and no significant effect on many common pathogens.

Moxifloxacin and bilateral acute iris transillumination

Recent publications have alerted clinicians to a syndrome of uveitic transilluminating iris depigmentation associated with systemic fluoroquinolones and other antibiotics. Bilateral acute iris transillumination, which is associated with loss of the iris pigment epithelium and results in iris transillumination, differs from the previously described bilateral acute depigmentation of the iris, which is associated with atrophy of the iris stroma without transillumination. We present a case of fluoroquinolone-associated uveitis with anterior segment optical coherence tomography imaging to highlight some observations about this syndrome. We interpret pharmacokinetic data to help explain why oral, but not topical, moxifloxacin may cause fluoroquinolone-associated uveitis.

Changes in antibiotic resistance patterns of conjunctival flora due to repeated use of topical antibiotics after intravitreal injection

OBJECTIVE

To determine the effect of repeated intermittent use of topical antibiotics after intravitreal injections on conjunctival bacterial flora and antibiotic resistance.

DESIGN

Cross-sectional case-control study.

PARTICIPANTS AND CONTROLS

A total of 80 eyes of 40 patients were enrolled (40 study eyes, 40 control eyes). Patients were enrolled with unilateral exudative age-related macular degeneration who had received at least 3 prior intravitreal injections with use of postinjection topical antibiotics. Patients had received an average of 7 (range, 3-13) intravitreal injections before enrollment.

METHODS

At the time of enrollment, the inferior fornix of the treated eye was swept with a culture swab before use of povidone iodine; the inferior fornix of the fellow eye was also cultured and served as a control. The culture and sensitivity data from the study and control eyes were analyzed.

MAIN OUTCOME MEASURES

The rate of antibiotic resistance among the conjunctival bacterial flora of the study eyes and control eyes.

RESULTS

A total of 80 eyes of 40 patients were enrolled in the study; 29 patients used trimethoprim/polymyxin B drops, and 11 patients used fluoroquinolone drops after each injection. A total of 58 bacterial colonies were isolated from 50 eyes. There were no significant differences in bacterial species or culture positivity rates between study and control eyes. Coagulase-negative staphylococcus accounted for 41 of the 58 bacterial colonies (71%). There was a 63.6% resistance rate to fluoroquinolones among study eyes compared with 32.1% among control eyes (P < 0.05). In the subset of 11 study eyes using fluoroquinolone drops for 4 days after injection, there was an 87.5% resistance rate compared with 25.0% in matched control eyes (P = 0.04). There was no significant difference in trimethoprim resistance rates between study and control eyes: Four of 14 study eyes (28.6%) showed resistance compared with 5 of 18 control eyes (27.7%) (P = 1.0).

CONCLUSIONS

Use of fluoroquinolone drops after intravitreal injection leads to increased rates of resistance among conjunctival flora. Repeated use of topical fluoroquinolones after intravitreal injections may have a detrimental effect on eye health by breeding resistance in the bacterial flora.

Prophylactic antibiotic use after intravitreal injection: effect on endophthalmitis rate

PURPOSE

Endophthalmitis after intravitreal injection is a serious complication. There are limited data to support the use of postinjection antibiotics to prevent endophthalmitis. Current endophthalmitis rates after intravitreal injection in the literature are based on studies where patients routinely received postinjection antibiotics. This study retrospectively compares the rate of endophthalmitis in a cohort of patients receiving postinjection antibiotics with that in a group that does not.

METHODS

A retrospective chart review was performed comparing a 12-month period where patients received postinjection topical antibiotics for several days after intravitreal injection with the next 12-month period where no postinjection topical antibiotics were used. Cases of suspected endophthalmitis after intravitreal injection during this period were identified and reviewed.

RESULTS

The rate of clinically suspected endophthalmitis in the cohort of patients receiving postinjection antibiotics after intravitreal injection and that in the cohort that did not was 0.22% and 0.20%, respectively. One culture-positive case was found overall. The difference between the 2 groups is not statistically significant (P = 0.75).

CONCLUSION

The rate of endophthalmitis after intravitreal injections administered in a clinical practice setting when aseptic technique is used is similar with or without the use of postinjection antibiotics.

Results at seven years after the use of intracamerular cefazolin as an endophthalmitis prophylaxis in cataract surgery

Background

To evaluate results after seven years using prophylactic intracameral cefazolin for the prevention of endophthalmitis in cataract surgery.

Methods

A prospective, observational study of all patients submitted to cataract surgery over the period January 1996 to December 2009. All cases of postoperative endophthalmitis over that period were reviewed. The patients were classified in two groups: Group 1 (11,696 patients) operated on between January 1996 and December 2002, Group 2 (13,305 patients) between January 2003 and December 2009 (in whom a 1 mg/0.1 bolus of intracameral cefazolin was instilled).

Results

During the study period, 76 cases of endophthalmitis were observed in Group 1, and seven in Group 2. The rate of postoperative endophthalmitis reduced from 0.63% to 0.05% with a cefazolin injection. The relative risk (RR) for endophthalmitis in Group 1 against group 2 was 11.45 [95% CI 5.72-22.84, p < 0.001].

Conclusions

An intracameral bolus injection of cefazolin (1 mg in 0.1 ml solution) at the conclusion of the cataract surgery significantly reduced the rate of postoperative endophthalmitis.

The role of topical moxifloxacin, a new antibacterial in Europe, in the treatment of bacterial conjunctivitis

This article discusses current practice in the treatment of conjunctivitis and how the use of topical moxifloxacin can increase therapeutic effectiveness, reduce treatment failures and, consequently, be cost effective and reduce the societal burden of the disorder. Current practice and effectiveness data were derived from the literature. Data on healthcare utilization as a result of treatment failure were collected by survey and the cost of treatment was defined using national costings. A decision-analytic model to assess cost effectiveness was developed and the impact on the healthcare budget was calculated to define the health economic impact. Bacterial conjunctivitis represents a significant health problem and accounts for an estimated 1-1.5% of primary-care consultations. The disorder is highly contagious and causes a substantial healthcare and societal burden. Bacterial conjunctivitis is generally self-limiting, resolving within 1-2 weeks. However, the use of antibacterials significantly improves clinical and microbiological remission, shortens symptom duration, and enables more effective use of healthcare resources, compared with placebo. From a health economic perspective this benefits the healthcare system and society, since fewer healthcare resources are needed and the adult affected, or the parent/caregiver of the child affected, can return to full work capacity sooner, reducing loss of productivity. Treatment strategies vary significantly between countries. Most patients are first seen in primary care, where 'wait-and-see', lubrification and antiseptic or antibacterial treatment is provided. In Europe, when antibacterials are prescribed most general practitioners (GPs) prescribe a broad-spectrum topical antibacterial. The most commonly used drugs are chloramphenicol and fusidic acid, with fluoroquinolones rarely reported as first-line treatment by GPs. At the specialist (ophthalmologist) level, or for second-line treatment at the GP level, topical antibacterials are frequently used. However, in most countries, topical fluoroquinolones, particularly those recently approved by the European Medicines Agency, such as topical levofloxacin and topical moxifloxacin, are rarely used and instead are reserved for use as a last resort. In other parts of the world topical lomefloxacin, gatifloxacin and/or besifloxacin are also available. The strategy of using novel topical fluoroquinolones as a last resort reflects a belief that the use of topical fluoroquinolones may enhance the development of resistance, jeopardizing future availability of antibacterial treatment for ocular infections. In fact, most cases of bacterial resistance arise as a result of systemic treatment. Thus, this concern should not be extrapolated to topical use of fluoroquinolones, which results in antibacterial concentrations at the ocular surface that can significantly exceed mutant prevention concentrations. In addition, with products such as topical moxifloxacin, a dual-step mutation is required for resistance to emerge. Moxifloxacin restricts the selection of resistant mutants, meaning that emergence of resistance is unlikely. The strategy of not using the most effective fluoroquinolones such as topical moxifloxacin may lead to more patients with no improvement or worsening of symptoms, requiring re-intervention, additional examination and new treatment; these outcomes are defined as 'treatment failures'. Treatment failures cause an extra societal burden and increased costs due to the extra healthcare resources required (additional GP/specialist visits, laboratory tests, additional treatment, etc.). Compared with non-fluoroquinolones, topical moxifloxacin has a higher potency and faster in vitro 'speed-to-kill'. It has also been shown that, within the fluoroquinolone class, topical moxifloxacin and besifloxacin achieve the highest mean concentrations in conjunctival tissue, have the longest residence times and display favourable area under the concentration-time curve from time zero to 24 hours (AUC(24))/minimum inhibitory concentration ratio required to inhibit the growth of 90% of organisms (MIC(90)) and thus favourable pharmacokinetic/pharmacodynamic characteristics. This can result in reduced time-to-cure and a lower number of treatment failures, leading to better disease management and a healthcare-economic benefit arising from the associated reduction in utilization of healthcare resources. The high potency and mean concentration in conjunctival tissue combined with the long residence time of topical moxifloxacin enables a dosing strategy of three times daily for 5 days. Topical moxifloxacin is also the first ophthalmic antibacterial in Europe provided as a multidose, self-preserved, topical solution, thus avoiding the risk of benzalkonium chloride preservative-related allergic reactions and swelling. In addition, topical moxifloxacin has a near neutral pH (6.8) and is well tolerated by patients. Given the characteristics of the novel topical fluoroquinolones, a change in the healthcare treatment strategy for acute infectious conjunctivitis is to be recommended. Topical application of fluoroquinolones, such as moxifloxacin multidose self-preserved solution, should be considered earlier in the treatment path for conjunctivitis. Notwithstanding the premium price attached to this novel topical antibacterial, use of topical moxifloxacin for bacterial conjunctivitis can be cost effective and even generate total healthcare budget savings by reducing both the costs of managing treatment failures and the use of clinicians' time to manage such failures.

Review of moxifloxacin hydrochloride ophthalmic solution in the treatment of bacterial eye infections

Moxifloxacin hydrochloride ophthalmic solution 0.5% (Vigamox((R))) is the ocular formulation/adaptation of moxifloxacin. Moxifloxacin is a broad spectrum 8-methoxyfluoroquinolone which terminates bacterial growth by binding to DNA gyrase (topoisomerase II) and topoisomerase IV, essential bacterial enzymes involved in the replication, translation, repair and recombination of deoxyribonucleic acid. Affinity for both enzymes improves potency and reduces the probability of selecting resistant bacterial subpopulations. Vigamox is a bactericidal, concentration dependent, anti-infective. It is preservative free, and well tolerated with minimal ocular side effects. It provides increased penetration into ocular tissues and fluids with improved activity against Streptococci and Staphylococci species and moderate to excellent activity against clinically relevant, gram-negative ocular pathogens.

Incidence and management of acute endophthalmitis after intravitreal bevacizumab (Avastin) injection

INTRODUCTION

The aim of this study was to report the incidence and management of acute endophthalmitis after intravitreal injection of Avastin (bevacizumab), and visual acuity outcomes of three eyes of three patients who developed acute endophthalmitis following intravitreal injection of Avastin.

METHODS

This clinical retrospective, non-comparative study included 3022 intravitreal injections of 1.25 mg bevacizumab consecutively performed for 1822 eyes with exudative age-related macular degeneration and other retinal diseases. Of 3022 injections, 1200 were reinjections. After clinical appearance of post-injection endophthalmitis, immediate intervention was performed, including injection of intravitreal antibiotics and early pars plana vitrectomy.

RESULTS

Three eyes of three patients with acute postoperative endophthalmitis were identified in the first week following intravitreal injections of 1.25 mg bevacizumab. Among of these patients, two cases were culture-positive and one case was culture-negative. Compared with presenting visual acuities, all of three patients improved at the end of follow-up time. The overall incidence rate of post-injection culture-proven endophthalmitis was 0.066%.

DISCUSSION

Acute culture-proven endophthalmitis is still a potential complication of intravitreal bevacizumab injection (approximately 0.066%) despite using maximal sterile techniques. Acute post-injection endophthalmitis following intravitreal bevacizumab occurs rapidly and can result in severe loss of vision. Prompt recognition and treatment are key in maximizing outcomes in patients who developed endophthalmitis after intravitreal injection of bevacizumab.

Uveitis-like syndrome and iris transillumination after the use of oral moxifloxacin

OBJECTIVE

To report a newly recognized adverse effect of oral moxifloxacin.

DESIGN

Observational case reports.

PARTICIPANTS

Five patients who used oral moxifloxacin therapy.

MAIN OUTCOME MEASURES

In five patients, a uveitis-like episode followed oral moxifloxacin therapy, afterwards they experienced photophobia. At slitlamp investigation, the patients showed almost complete iris transillumination, not restricted to one sector, and persistent mydriasis of the pupil, with no reaction to light and no near reflex. Follow-up of 3 years in one of the patients showed no change of symptoms. Only in one patient, with a history of anterior uveitis, an anterior chamber tap was positive for herpes simplex genome. Only after the use of moxifloxacin did she experience continuous photophobia.

CONCLUSIONS

Iris transillumination and sphincter paralysis is a newly recognized adverse effect of oral moxifloxacin therapy.

[Intracameral moxifloxacin: a safe option for endophthalmitis prophylaxis? In vitro safety profile for intraocular application]

BACKGROUND

Moxifloxacin (Vigamox), a 4th-generation fluoroquinolone, covers most isolates causing endophthalmitis. It is safe and effective for systemic and topical use; however, only very limited data are available on prophylactic intracameral administration to prevent endophthalmitis. This study investigated the safety of Vigamox for intracameral application in a cell-culture model.

METHODS

The endothelial toxicity of moxifloxacin (Vigamox) was evaluated in cultured human corneas. Primary human retinal pigment epithelium cells (RPEs), trabecular meshwork cells (TMCs), lens epithelium cells (LECs), and corneal endothelial cells (CECs) were treated with concentrations of Vigamox. Toxic effects were evaluated after 24 h (MTT assay and live-dead assay). By treating TMC, CEC, and RPE cells either with oxidative stress or tumor necrosis factor-alpha (TNF-a), lipopolysaccharide (LPS), and interleukin-6 (IL-6), the effects of moxifloxacin on cellular viability under conditions of inflammation were investigated.

RESULTS

No corneal endothelial toxicity could be detected after 30 days of treatment with moxifloxacin 500 microg/ml. Primary RPEs, TMCs, LECs, and CECs showed adverse effects on proliferation and viability only at concentrations higher than 150 microg/ml moxifloxacin. After preincubation with TNF-a, LPS, and IL-6 for 24 h and subsequent treatment with moxifloxacin at concentrations of 10-150 microg/ml for 24 h, no significant decrease in proliferation or viability was observed. H2O2 exposure did not increase cellular toxicity

CONCLUSION

Vigamox did not show significant toxicity on primary RPEs, TMCs, LECs, CECs, or human corneal endothelium at concentrations up to 150 microg/ml. The MIC90 of moxifloxacin for pathogens commonly encountered in endophthalmitis is known to be in the range of 0.25-2.5 microg/ml. Therefore, intracameral use of Vigamox at concentrations up to 150 microg/ml may be safe and effective for preventing endophthalmitis after intraocular surgery.

Antibiotic resistance of conjunctiva and nasopharynx evaluation study: a prospective study of patients undergoing intravitreal injections

PURPOSE

To determine the baseline antibiotic susceptibility patterns of conjunctival and nasopharyngeal flora isolated from patients undergoing intravitreal (IVT) injections for choroidal neovascularization (CNV).

DESIGN

Prospective, observational study.

PARTICIPANTS

Forty-eight eyes of 24 patients undergoing unilateral IVT injections for CNV.

METHODS

Bilateral conjunctival and unilateral nasopharyngeal cultures on the treatment side were taken before application of any topical medications.

MAIN OUTCOME MEASURES

Bacterial isolates were identified and tested for antibiotic susceptibility to 16 different antibiotics using the Kirby-Bauer disc diffusion technique.

RESULTS

A total of 57 bacterial isolates were obtained from the conjunctiva of 48 eyes. Coagulase-negative staphylococci (CNS) accounted for 37 of the 57 isolates (65%). The most common CNS organisms were Staphylococcus epidermidis and Staphylococcus lugdunensis accounting for 73% and 11% of CNS isolates, respectively. More than half of S. epidermidis isolates demonstrated some level of resistance to ofloxacin and levofloxacin, and 33% and 37% of isolates showed some level of resistance against gatifloxacin and moxifloxacin, respectively. Some 60% and 30% of CNS isolates were resistant to ≥ 3 and ≥ 5 antibiotics, respectively. Among the 24 nasopharyngeal cultures, 8 (33%) grew Staphylococcus aureus, and 1 of the 8 isolates (13%) was resistant to all penicillin, cephalosporin, macrolide, and fluoroquinolone antibiotics tested.

CONCLUSIONS

Our results demonstrate subtantial levels of resistance to third- and fourth-generation fluoroquinolones and multiresistance among ocular CNS isolated from patients undergoing IVT injections for CNV.

Endophthalmitis: Pathogenesis, clinical presentation, management, and perspectives

Endophthalmitis is a rare but sight-threatening complication that can occur after ocular surgery or trauma or as a consequence of systemic infection. To optimize visual outcome, early diagnosis and treatment are essential. Over recent decades, advances in hygienic standards, improved microbiologic and surgical techniques, development of powerful antimicrobial drugs, and the introduction of intravitreal antibiotic therapy have led to a decreased incidence and improved management of endophthalmitis. However, endophthalmitis still represents a serious clinical problem. This review focuses on current principles and techniques for evaluation and treatment of endophthalmitis. In addition, it addresses recent developments regarding antimicrobial treatment and prophylaxis of infectious endophthalmitis.

Risk of endophthalmitis after intravitreal drug injection when topical antibiotics are not required: the diabetic retinopathy clinical research network laser-ranibizumab-triamcinolone clinical trials

OBJECTIVE

To report the incidence of endophthalmitis after intravitreal drug injection by means of a standardized procedure that does not require topical antibiotics, sterile gloves, or a sterile drape.

METHODS

Intravitreal injections of preservative-free triamcinolone acetonide or ranibizumab were administered in 2 prospective randomized clinical trials performed by the Diabetic Retinopathy Clinical Research Network. The standardized procedure for these trials requires the use of a topical combination product of povidone-iodine, a sterile lid speculum, and topical anesthetic, but does not require the use of topical antibiotics before, on the day of, or after injection.

RESULTS

As of February 23, 2009, a total of 3226 intravitreal injections of ranibizumab and 612 injections of preservative-free triamcinolone had been administered. Topical antibiotics were given on the day of injection in 361 (9.4%) of the 3838 cases, for several days after injection in 813 cases (21.2%), on the day of injection and after injection in 1388 cases (36.2%), and neither on the day of injection nor after injection in 1276 cases (33.3%). Three cases of culture-positive endophthalmitis occurred after ranibizumab injections (0.09%), and no cases occurred after triamcinolone injections. In all 3 cases of endophthalmitis, topical antibiotics were given for several days after the injection but not before injection.

CONCLUSIONS

The results suggest that a low rate of endophthalmitis can be achieved by means of a protocol that includes use of topical povidone-iodine, a sterile lid speculum, and topical anesthetic, but does not require topical antibiotics, sterile gloves, or a sterile drape. Trial Registration clinicaltrials.gov Identifiers: NCT00444600 and NCT00445003.

Ocular pharmacokinetics of besifloxacin following topical administration to rabbits, monkeys, and humans

PURPOSE

Studies were conducted to evaluate the ocular penetration and systemic exposure to besifloxacin, a fluoroquinolone antibiotic, following topical ocular administration to animals and humans.

METHODS

Besifloxacin ophthalmic suspension (0.6%) was administered as a topical ocular instillation to pigmented rabbits, cynomolgus monkeys, and human subjects. At predetermined intervals after dosing, samples of ocular tissues and plasma were collected and analyzed for besifloxacin levels using HPLC/MS/MS methods.

RESULTS

Besifloxacin demonstrated good ocular penetration in rabbits and monkeys, with rapid absorption and sustained concentrations observed in anterior ocular tissues through 24 h after a single administration. Maximum besifloxacin concentrations in conjunctiva, cornea, and aqueous humor of monkeys were 6.43 microg/g, 2.10 microg/g, and 0.796 microg/mL, respectively, after a single topical dose, and concentrations declined in these tissues with an apparent half-life of 5-14 h. Following a single topical ocular administration to humans, the maximum besifloxacin concentration in tears was 610 microg/g with concentrations decreasing to approximately 1.6 microg/g at 24 h. The resulting pharmacokinetic parameters for besifloxacin in human tears were evaluated relative to the MIC(90) values (microg/mL) for besifloxacin against Streptococcus pneumoniae (0.125), Staphylococcus aureus (0.25), Staphylococcus epidermidis (0.5), and Haemophilus influenzae (0.06). Following a single topical administration, the C(max)/MIC(90) ratios for besifloxacin in human tears were > or =1,220, and the AUC((0-24))/MIC(90) ratios were > or =2,500 for these relevant ocular pathogens. Following repeated 3-times daily (TID) topical ocular administration to human subjects with clinically diagnosed bacterial conjunctivitis, maximum besifloxacin concentrations in plasma were less than 0.5 ng/mL, on average.

CONCLUSIONS

Taken together, the results of the current investigation provide a PK/PD-based rationale that supports the use of besifloxacin for the safe and effective treatment of ocular infections.

Intracameral moxifloxacin: in vitro safety on human ocular cells

PURPOSE

The fourth-generation fluoroquinolone, moxifloxacin, covers most gram-positive and gram-negative isolates causing endophthalmitis. It is safe and effective for systemic and topical use, but only limited data are available on prophylactic intracameral administration to prevent endophthalmitis. This study uses a cell culture model to investigate the safety of moxifloxacin for intracameral application.

METHODS

Endothelial toxicity of moxifloxacin was evaluated in cultured human corneas. Possible toxic effects of moxifloxacin (10-750 microg/mL) in corneal endothelial cells (CEC), primary human trabecular meshwork cells (TMC), and primary human retinal pigment epithelial (RPE) cells were evaluated after 24 hours and under conditions of oxidative and inflammatory stress by treatment with tumor necrosis factor alpha, lipopolysaccharides, or interleukin-6. Toxicity was evaluated by tetrazolium dye reduction assay, and cell viability was quantified by a microscopic live-dead assay.

RESULTS

No corneal endothelial toxicity could be detected after 30 days of treatment with 500 microg/mL moxifloxacin. Concentrations up to 150 microg/mL had no influence on CEC, TMC, or RPE cell proliferation or on cell viability when administered for 24 hours. After preincubation with tumor necrosis factor alpha, lipopolysaccharides, or interleukin-6 for 24 hours and subsequent treatment with moxifloxacin at concentrations from 10 to 150 microg/mL for 24 hours, no significant decrease in proliferation or viability was observed. Hydrogen peroxide exposure did not increase cellular toxicity.

CONCLUSIONS

This study showed no significant toxicity for moxifloxacin on CEC, TMC, RPE cells, or human corneal endothelium for concentrations up to 150 microg/mL. The minimum inhibitory concentration of moxifloxacin to inhibit 90% of pathogens commonly encountered in endophthalmitis is known to be in the range of 0.25-2.5 microg/mL. Therefore, prophylactic intracameral use of moxifloxacin at concentrations up to 150 microg/mL may be safely used to prevent endophthalmitis after intraocular surgery.

Calculation of AQCmax: comparison of five ophthalmic fluoroquinolone solutions*

ABSTRACT Objective: Ocular tissue penetration of five different ophthalmic fluoroquinolone solutions in the rabbit eye was measured and evaluated by an index of the maximum aqueous concentration (AQCmax).

METHODS

Moxifloxacin 0.5% (MFLX), levofloxacin 0.5% (LVFX), gatifloxacin 0.3% (GFLX), ofloxacin 0.3% (OFLX), or tosufloxacin tosilate 0.3% (TFLX) were instilled into the eyes of white rabbits every 15 min for a total of three doses. Aqueous humor, cornea, iris/ciliary body and vitreous body were collected 10 to 240 min after instillation and drug concentrations were measured by high-performance liquid chromatography.

RESULTS

The concentration of MFLX was the highest in each tissue, with maximum concentrations of MFLX in the aqueous humor (10.16 +/- 1.59 microg/mL) at 30 min after instillation, cornea (156.07 +/- 95.97 microg/g) and iris/ciliary body (11.92 +/- 4.00 microg/g) at 10 min after instillation, and vitreous body (0.099 +/- 0.033 microg/mL) at 30 min after instillation. The concentration of TFLX was the lowest in each tissue, with LVFX, GFLX, and OFLX sharing the mid-ranks. AQCmax : MIC(90) ratio for S. aureus was 150.67 for MFLX, 10.6 for LVFX, 9.69 for GFLX, 3.48 for OFLX, and could not be determined for TFLX.

CONCLUSION

AQCmax is a useful pharmacokinetic parameter for determining the therapeutic efficacy of an ophthalmic antibiotic, especially when combined with MIC(90) values for intraocular pathogens. C(max) of MFLX ophthalmic solution was superior in all tissues (cornea, aqueous humor, iris/ciliary body and vitreous body) among the five ophthalmic solutions studied, exceeding the MIC(90) of S. aureus in all tissues, and MIC(90)s of S. epidermidis, B. cereus, and P. acnes in aqueous humor, cornea, and iris/ciliary body. AQCmax was approximately proportional to C(max) in iris/ciliary body and vitreous, and may be used in combination with MIC(90)s as an index to predict the most appropriate dose and frequency of ophthalmic antibiotics in conjunction with other PK/PD parameters. This study may provide the groundwork for calculation of AQCmax in humans.