Ocular pharmacokinetics, safety and efficacy of intracameral moxifloxacin 0.5% solution in a rabbit model

Intracameral Drug Delivery: A Review of Agents, Indications, and Outcomes

An intracameral (IC) injection directly delivers the drug into the anterior chamber of the eye. This targeted drug delivery technique overcomes the ocular barriers and offers a high therapeutic concentration of medication at the desired site and consequently better clinical outcomes. IC drug delivery is a safe and effective modality with many advantages over topical delivery. These include excellent bioavailability, reduced systemic risk, and minimal ocular toxicity. Agents delivered via IC injection have shown promising results against infection, inflammation, ocular hypertension, and neovascularization. Current literature shows that IC antibiotics, including cefuroxime, vancomycin, and moxifloxacin, are routinely used for prophylaxis of endophthalmitis. Other drugs available for IC use are steroids, anesthetics, mydriatics, miotics, antivascular endothelial growth factor, antiglaucoma, and alkylating agents. Introduction of sustained-release devices containing dexamethasone or Bimatoprost in anterior chamber via IC route has the potential in treating ocular inflammation and raised intraocular pressure. The complications such as hemorrhagic occlusive retinal vasculitis and toxic anterior segment syndrome have been documented with IC prophylaxis but are rare. In this review, we provide an overview of available IC drugs, their pharmacokinetics, the spectrum of activity, dosage and preparation, prophylactic and therapeutic usage, clinical efficacy, and safety profiles.

Impact on corneal morphology after cataract surgery with intracameral moxifloxacin in neglected hard cataracts

AIM

To evaluate corneal morphology after use of 0.5% intracameral moxifloxacin (ICM) in cataract surgery in patients who presented late with hard cataracts.

METHODS

Cross-sectional study conducted from June-2021 to December-2021 at a tertiary eye-care center. 90 patients over 60 years with high-risk characteristics for Covid-19, who presented late with higher grades of nuclear-sclerosis (NS), were included. They underwent phacoemulsification and 0.5%moxifloxacin (0.1 ml) was injected intracamerally at the end of surgery. Best-corrected visual acuity (BCVA), intraocular pressures (IOP), endothelial cell density (ECD), coefficient of variation in cell-area (CoV), hexagonality (Hex) and central corneal thickness (CCT) were measured preoperatively and postoperatively on day1, day7 and day30. Statistical analysis was done by Anova test. p-value<0.05 was considered significant.

RESULTS

Mean age of presentation was 65.26±8.3 years. Mean preoperative BCVA (1/60-to-6/60), IOP (16.7±2.3 mm of Hg), CCT (523.93±39.6µ), ECD (2547±302.08cells/mm2), Hex (47.04±5.7%) and CoV (37.57±3.9) changed to BCVA (6/9-to-6/6), IOP (17.5±2.1 mm of Hg), CCT (538.42±36.9µ), ECD (2388.40±339.25cells/mm2), Hex (44.44±5.6%) and CoV (39.09±4.5) at day30 postoperative. Average rate of change at day30 was increase in CCT (2.89%), ECD loss (6.4%), decrease in Hex (4.9%) and increase in CoV (4.6%), though clinically insignificant. No case of endophthalmitis or toxic-anterior segment syndrome seen.

CONCLUSION

0.5% moxifloxacin (0.1 ml) is safe as intracameral antibiotic to prevent postoperative infection in high-risk patients. The reported changes in the corneal parameters were within the range of any routine surgeries of hard senile cataracts. No specific effect could be attributed to ICM.

Advances in ophthalmic drug delivery technology for postoperative management after cataract surgery

INTRODUCTION

Cataract surgery is becoming more common due to an aging world population. Intraocular lenses and surgical technique have developed remarkably recently, but the development of postoperative medication to prevent postsurgery complications has been relatively delayed. We still largely depend on eye drops for the management of post-cataract-surgery patients. Mental and physical problems that often occur in elderly cataract patients make it difficult for patients to apply eye drops by themselves. It is necessary to develop new effective drug delivery methods.

AREAS COVERED

This updated review article provides a brief review of why drug management is needed following cataract surgery and an overview of current developments in new drug delivery methods for ophthalmic treatment. In particular, various novel drug delivery methods that can be used for post-cataract-surgery management and their current development stages are extensively reviewed.

EXPERT OPINION

Rapidly developing technologies, such as intraocular and external ophthalmic implants, polymers, and nanotechnology, are being actively applied to develop novel drug delivery systems for safe and effective management after cataract surgery. Their goal is to achieve sufficient drug release for the desired duration with a single application. These will largely replace the inconvenience of eye drops for elderly patients in the future.

Clinical features and microbiology of post-cataract surgery endophthalmitis with and without intracameral moxifloxacin prophylaxis: Endophthalmitis prophylaxis study report 3

Purpose:

This study aimed to analyze the clinical presentations, microbiology, and management outcomes of post–cataract surgery endophthalmitis, with and without intracameral moxifloxacin prophylaxis.

Methods:

This study was designed as a retrospective, consecutive, comparative case series. Records of consecutive cataract surgery from January 1, 2015, till June 30, 2020, were analyzed. The cases that developed endophthalmitis were analyzed. The endophthalmitis cases were divided by their prophylaxis treatment into two groups: with intracameral moxifloxacin (ICM) and without (N-ICM). Inclusion criteria were (1) age ≥ 18 years, (2) cataract surgery with intraocular lens implantation, (3) endophthalmitis within 6 weeks of cataract surgery, and (4) cataract surgery in the institute by any of the three methods—phacoemulsification, manual small incision cataract surgery, and extracapsular cataract extraction.

Results:

In the study period, 66,967 cataract surgeries were performed; 48.7% (n = 32,649) did not receive ICM. There was no difference between the N-ICM and ICM groups in the incidence of clinical (n = 21, 0.064% and n = 15, 0.043%; P = 0.23) and culture proven (n = 19, 0.033% and n = 11, 0.023%; P = 0.99) endophthalmitis, respectively. Greater number of patients in the N-ICM group had lid edema (76.2% vs. 40%; P = 0.03), corneal edema (71.4% vs. 33.3%; P = 0.03) and lower presenting vision with available correction (logMAR [logarithm of the minimum angle of resolution] 1.26 ± 1.2 vs. logMAR 0.54 ± 0.85; P = 0.02). The final best-corrected visual acuity following treatment was worse in the N-ICM group (logMAR 1.26 ± 1.2 vs. 0.54 ± 0.85; P = 0.02).

Conclusion:

Endophthalmitis after intracameral moxifloxacin may have relatively milder signs and symptoms and may respond better to treatment.

Moxifloxacin releasing intraocular implant based on a cross-linked hyaluronic acid membrane

Intraocular antibiotic delivery is an important technique to prevent bacterial infection after ophthalmic surgery, such as cataract surgery. Conventional drug delivery methods, such as antibiotic eye drops, have limitations for intraocular drug delivery due to the intrinsic barrier effect of the cornea. Therefore, frequent instillation of antibiotic eyedrops is necessary to reach a sufficient bactericidal concentration inside the eye. In this study, an intraocular implant, MXF-HA, that combines hyaluronic acid (HA) and moxifloxacin (MXF) was developed to increase the efficiency of intraocular drug delivery after surgery. MXF-HA is manufactured as a thin, transparent, yellow-tinted membrane. When inserted into the eye in a dry state, MXF-HA is naturally hydrated and settles in the eye, and the MXF contained therein is delivered by hydrolysis of the polymer over time. It was confirmed through in vivo experiments that MXF delivery was maintained in the anterior chamber of the eye at a concentration sufficient to inhibit Pseudomonas aeruginosa and Staphylococcus aureus for more than 5 days after implantation. These results suggest that MXF-HA can be utilized as a potential drug delivery method for the prevention and treatment of bacterial infections after ophthalmic surgery.

An ion-paired moxifloxacin nanosuspension eye drop provides improved prevention and treatment of ocular infection

There are numerous barriers to achieving effective intraocular drug administration, including the mucus layer protecting the ocular surface. For this reason, antibiotic eye drops must be used multiple times per day to prevent and treat ocular infections. Frequent eye drop use is inconvenient for patients, and lack of adherence to prescribed dosing regimens limits treatment efficacy and contributes to antibiotic resistance. Here, we describe an ion-pairing approach used to create an insoluble moxifloxacin-pamoate (MOX-PAM) complex for formulation into mucus-penetrating nanosuspension eye drops (MOX-PAM NS). The MOX-PAM NS provided a significant increase in ocular drug absorption, as measured by the area under the curve in cornea tissue and aqueous humor, compared to Vigamox in healthy rats. Prophylactic and treatment efficacy were evaluated in a rat model of ocular Staphylococcus aureus infection. A single drop of MOX-PAM NS was more effective than Vigamox, and completely prevented infection. Once a day dosing with MOX-PAM NS was similar, if not more effective, than three times a day dosing with Vigamox for treating S. aureus infection. The MOX-PAM NS provided increased intraocular antibiotic absorption and improved prevention and treatment of ocular keratitis, and the formulation approach is highly translational and clinically relevant.

Evaluation of moxifloxacin-induced cytotoxicity on human corneal endothelial cells

Moxifloxacin hydrochloride (MXF) is widely used for the prevention of bacterial endophthalmitis after intraocular surgeries. However, the safety issue of intracameral injection of MXF for human corneal endothelial cells (HCECs) is still debatable. In this study, we investigated concentration-dependent cytotoxicity (0.05–1 mg/ml) of MXF for immortalized HCECs (B4G12 cell) and the underlying mechanism. Reactive oxygen generation (ROS) and cell viability after MXF exposure was measured. Flow cytometric analysis and TUNEL assay was used to detect apoptotic HCECs after MXF exposure. Ultrastructure of damaged HCECs by MXF was imaged by transmission electron microscope. Western blot analysis and caspase 2, 3 and 8 analysis were used to reveal the underlying mechanism of MXF induced damage in HCECs. We found that MXF induced dose-dependent cytotoxicity in HCECs. MXF exposure increased ROS generation and induced autophagy in HCECs. Increased LDH release represented the cellular membrane damage by MXF. In addition, caspases activation, Bax/Bcl-xL-dependent apoptosis pathway and apoptosis inducing factor nuclear translocation were all involved in MXF induced HCECs’ damage, especially after exposure to high dose of MXF (0.5 and 1.0 mg/ml). These findings suggest that MXF toxicity on HCECs should be thoroughly considered by ophthalmologists when intracameral injection of MXF is planned.

Endophthalmitis prophylaxis by intracameral antibiotics: In vitro model comparing vancomycin, cefuroxime, and moxifloxacin

PURPOSE

To compare the efficacy of intracameral vancomycin, cefuroxime, and moxifloxacin on postoperative bacterial endophthalmitis rates.

SETTING

Norwalk Hospital, Norwalk, Connecticut, USA.

DESIGN

Experimental study.

METHODS

Bacteria and intraocular lenses (IOLs) were incubated with vancomycin, cefuroxime, moxifloxacin, or combinations. Antibiotic concentrations were high, corresponding to clinical maximum intracameral doses (1.0 mg vancomycin or cefuroxime, 0.5 mg moxifloxacin), or low (one third of clinical maximum dose). The following bacteria were isolated from patients with endophthalmitis: 18 strains including 6 staphylococci, 6 streptococci, 3 pseudomonad, and 3 propionibacteria. Samples were diluted by half every 2 hours to model the half-life of intracameral antibiotics. At 24 hours, samples were vortexed to shake bacterial biofilms loose from the IOLs. The bacterial broth was plated and colonies were counted 24 hours later.

RESULTS

Efficacy against staphylococci was concentration dependent; all antibiotics were effective at high concentrations, while low concentrations were in general ineffective. Streptococci and propionibacteria were nearly eliminated by all antibiotics at low concentrations. Pseudomonads were most effectively treated by high-dose moxifloxacin and its combinations.

CONCLUSIONS

Broadest coverage against common pathogens should be obtained by high-dose moxifloxacin (0.5 mg intracameral). Submaximum dosing, which could occur if aqueous is released to lower intraocular pressure after injection, compromises the efficacy against staphylococci and pseudomonads. All antibiotics, even at low doses, were effective against streptococci and propionibacteria, suggesting that many of the worst endophthalmitis outcomes could be prevented by intracameral use of any of the 3 antibiotics used in this study.

Comparative analysis of the safety and efficacy of intracameral cefuroxime, moxifloxacin and vancomycin at the end of cataract surgery: a meta-analysis

BACKGROUND

Current practice methods are unclear as to the most safe and effective prophylactic pharmacotherapy and method of delivery to reduce postoperative endophthalmitis occurrence.

METHODS

A systematic review and meta-analysis using Meta-analysis of Observational Studies in Epidemiology guidelines was performed to compare the efficacy of intracameral cefuroxime, moxifloxacin and vancomycin in preventing postphacoemulsification cataract surgery endophthalmitis. A safety analysis of intracameral antibiotics was concurrently performed.

DATA SOURCES

BIOSIS Previews, CINAHL, ClinicalTrials.gov, Cochrane Library, Dissertations & Theses, EMBASE, PubMed, ScienceDirect and Scopus were searched from inception to January 2017. Data were pooled using a random effects model. All articles were individually reviewed and data were extracted by two independent reviewers. Funnel plot, risk of bias and quality of evidence analyses were performed.

RESULTS

Seventeen studies with over 900 000 eyes were included, which favoured the use of intracameral antibiotics at the end of cataract surgery (OR 0.20; 95% CI 0.13 to 0.32; P<0.00001). The average weighted postoperative endophthalmitis incidence rates with intracameral cefuroxime, moxifloxacin and vancomycin were 0.0332%, 0.0153% and 0.0106%, respectively. Secondary analyses showed no difference in efficacy between intracameral plus topical antibiotics versus intracameral alone (P>0.3). Most studies had low to moderate risk of bias. The safety analysis showed minimal toxicity for moxifloxacin. Dosing errors led to the majority of toxicities with cefuroxime. Although rare, vancomycin was associated with toxic retinal events.

CONCLUSION

Intracameral cefuroxime and moxifloxacin reduced endophthalmitis rates compared with controls with minimal or no toxicity events at standard doses. Additionally, intracameral antibiotics alone may be as effective as intracameral plus topical antibiotics.

Diagnosis and Treatment of Listeria monocytogenes Endophthalmitis: A Systematic Review

PURPOSE

Describe patient characteristics, treatment, and vision outcomes of Listeria monocytogenes endophthalmitis, an exceedingly rare form of listeriosis.

METHODS

L. monocytogenes endophthalmitis cases in human adults, located through Medline (32) and from disease surveillance centers (11). L. monocytogenes conjunctivitis and keratitis were excluded.

RESULTS

Most cases occurred in 2000-2015 (22/43), and almost all in Europe or North America (40/43). Patients were a median 61 years, 57% male (24/42) and half were immunosuppressed. Median days from entering care to diagnosis was 8 (IQR = 5-17). Only four were exogenous infections. L. monocytogenes was identified in 31/35 of anterior eye fluid samples (89%). Antibiotic regimens varied markedly (mostly ≥3 drugs). At diagnosis, most were blind in the affected eye (85%, 28/33), only a third regained normal vision (12/36). Older patients had poorer outcomes.

CONCLUSIONS

Cases increased over time. Diagnostic delays were common and visual impairment often refractory to treatment, especially in older adults. The condition's rarity and variation in treatment makes it difficult to identify optimum therapy.

Ocular Pharmacokinetics

Although the fundamental concepts of pharmacokinetics remain the same, ocular pharmacokinetics has its own challenges due to the uniqueness of barrier properties posed by various ocular tissues and its growing complexity with different routes of ocular administration. A thorough understanding of the barrier nature will aid in tailoring a drug or its carrier's physicochemical properties to its advantage. In order to deliver the right payload of a drug at the target site, various approaches can be taken to leverage the pharmacokinetics that includes molecular design based on desirable physicochemical properties, formulation approaches, and alternative routes of administration. In this chapter, a brief overview of the barrier properties with respect to various routes of administration is presented along with the physicochemical properties that influence the pharmacokinetics of ocular drugs. Recent advances in ocular pharmacokinetics are discussed in addition to new perspectives in interpreting existing data.

[Ocular toxicity of intracamerally injected antibacterial and antifungal drugs (experimental and morphological study)]

OBJECTIVE

To study anterior eye segment toxicity of variously diluted brand name and generic antibiotic and antifungal drugs, including domestically produced generics (Moxifloxacin, asketin cefuroxime, amikacin, gentamicin, Diflucan, and amphotericin B), experimentally injected into the anterior chamber.

MATERIAL AND METHODS

A total of 13 Chinchilla rabbits were included in the experiment. Group 1 (6 rabbits) received sterile intracameral injections of 0.2 ml antibiotics and antifungals in concentrations suitable for intravenous administration (Moxifloxacin 1.6 mg/ml, Diflucan 2 mg/ml, and the following generics: asketin cefuroxime 125 mg/ml, amikacin 50 mg/ml, gentamicin 40 mg/ml, amphotericin B 50 mg/m). BSS was injected into the fellow eye for control. Group 2 (7 rabbits) also received sterile intracameral injections of 0.2 ml antibiotics and antifungals, which were the same as for group 1 but highly diluted (Moxifloxacin 150 μg/ml and 500 μg/ml, Diflucan 10 μg/ml, asketin cefuroxime 1 mg/ml, gentamicin 200 μg/ml, amikacin 400 μg/ml, amphotericin B 10 μg/ml).

RESULTS

There were no toxic effects in group 1 after BSS and Moxifloxacin 1.6 mg/ml injections into the anterior chamber. However, high concentrations of other antibiotic and antifungal drugs were associated with changes in the corneal endothelium of various severity (from cytoplasmic swelling of the endothelial cells to their complete desquamation), as well as fibrin exudation in the posterior chamber. In group 2 neither of injected drugs caused toxic, allergic, or inflammatory reactions according to histopathological examination.

CONCLUSION

The experiment proved safety of the intracameral route of administration for highly diluted medications from the list and also demonstrated the absence of toxic reaction after intracameral injection of Moxifloxacin 1.6 mg/ml.

Toxic anterior segment syndrome after uncomplicated cataract surgery possibly associated with intracamaral use of cefuroxime

Purpose

To report toxic anterior segment syndrome (TASS) after cataract surgery possibly associated with intracameral use of cefuroxime.

Methods

We conducted a retrospective chart review and analysis on the pre- and postoperative conditions of the subjects who had developed TASS.

Results

The patient group consisted of 17 patients. Tyndallization and fibrin fibers were positive in all eyes. In four eyes, hypopyon formation developed. These reactions diminished on the third day and fully resolved 1 week after the operations with the use of intensive topical steroid and mydriatic therapy. To determine the etiology of TASS, infusion fluid, viscoelastics, and intracameral antibiotic agent were changed respectively. After changing intracameral antibiotic agent from cefuroxime axetile to moxifloxacin no new cases of TASS were diagnosed.

Conclusion

All agents injected into the anterior chamber can cause TASS. Ophthalmologists and operating room staff need to pay careful attention to all drugs and irrigating solutions.

Ocular penetration and efficacy of levofloxacin using different drug-delivery techniques for the prevention of endophthalmitis in rabbit eyes with posterior capsule rupture

PURPOSE

To evaluate the effects of different drug-delivery techniques for levofloxacin (LVFX) in ocular penetration and the prevention of endophthalmitis using an aphakic rabbit model with posterior capsule rupture (PCR).

METHODS

LVFX was administered to aphakic rabbit eyes with or without PCR using eye drops (EDs), subconjunctival injection (SCI), or intracameral (IC) injection. The concentration of the drug in the vitreous and aqueous humors was estimated at 2 h after injection. In another study, aphakic rabbit eyes with PCR were inoculated with Enterococcus faecalis, immediately followed by 0.5% LVFX ED, 0.5% moxifloxacin (MFLX) ED, LVFX IC (500 μg/0.1 mL), or IC saline. EDs were administered 0, 3, and 6 h after surgery. Changes on electroretinography (ERG) and intraocular bacterial growth were determined sequentially until 48 h after inoculation.

RESULTS

The concentrations of LVFX at 2 h after IC were higher in the aqueous humor and the vitreous cavity of eyes with or without PCR, compared with EDs or SCI. Eyes treated with LVFX ED, MFLX ED, or IC saline showed a significantly greater reduction in b-wave amplitude on ERG at 48 h compared with eyes treated with LVFX IC. The number of bacteria recovered from the vitreous humor in eyes treated with IC LVFX at 48 h was significantly less than from eyes that received other treatments.

CONCLUSION

The LVFX IC was effective at suppressing endophthalmitis caused by E. faecalis in eyes with a PCR.

Efficacy and safety of prophylactic intracameral moxifloxacin injection in Japan

PURPOSE

To report endophthalmitis rates after cataract surgery and the incidence of complications after intracameral moxifloxacin injection.

SETTING

Nineteen clinics in Japanese institutions.

DESIGN

Retrospective survey cohort study.

METHODS

The number of surgeries and endophthalmitis cases in the past 4 years before and after the introduction of intracameral moxifloxacin was evaluated. The survey was performed by mail or interview in February 2013.

RESULTS

All institutions used total-replacement administration rather than small-volume injection. At 3 institutions, 50 to 100 μg/mL moxifloxacin; at 9 institutions, 100 to 300 μg/mL moxifloxacin; and at 7 institutions, 500 μg/mL moxifloxacin was administered. The highest concentration (500 μg/mL) was administered in 14,124 cases. Endophthalmitis cases occurred 1 month or sooner postoperatively in 8 of 15,958 cases (ie, 1 in 1955) without intracameral moxifloxacin administration and in 3 of 18,794 cases (ie, 1 in 6265) with intracameral moxifloxacin administration.

CONCLUSIONS

Intracameral moxifloxacin (50 to 500 μg/mL) administration decreased the risk for endophthalmitis by 3-fold. In more than 18,000 cases, moxifloxacin administration of 500 μg/mL or less did not result in severe complications, such as toxic anterior segment syndrome or corneal endothelial cell loss.