Comparison of in vitro Susceptibilities of Ocular Bacterial Isolates to Gatifloxacin and Other Topical Antibiotics

Kaliamurthy, Jayaraman; Jesudasan, Christadoss Arul Nelson; Geraldine, Pitchairaj; Parmar, Pragya; Kalavathy, C M; Thomas, Philip A.

doi:10.1159/000084270

Cited by 39 publications

(23 citation statements)

References 42 publications

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“…13,14 Studies have shown that topical gatifloxacin solution may be effective in prevention of infectious conditions such as conjunctivitis, keratitis, and postcataract endophthalmitis. 15,16 Owing to the benefits offered by gatifloxacin, various manufacturers have introduced gatifloxacin eyedrops (0.3% wt/vol). Fluoroquinolones have pHdependent solubility.…”

Section: Introductionmentioning

confidence: 99%

Effect of formulation factors on in vitro transcorneal permeation of gatifloxacin from aqueous drops

Majumdar

2006

AAPS PharmSciTech

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The purpose of this research was to optimize the formulation factors for maximum in vitro permeation of gatifloxacin from aqueous drops through excised goat cornea and to evaluate the permeation characteristics of drug from selected marketed eyedrop formulations. Permeation studies were conducted by putting 1 mL of formulation on the cornea (0.67 cm 2 ) fixed between the donor and receptor compartments of an all-glass modified Franz diffusion cell and measuring gatifloxacin concentration in the receptor (containing normal saline under stirring) by spectrophotometry at 291.5 nm, after 120 minutes. Raising the drug concentration of the drops increased the drug permeation but decreased the percent permeation and the in vitro ocular availability. Raising the pH of the formulation from pH 5 to 7.2 increased both the drug permeation and the in vitro ocular availability. Eyedrops containing benzalkonium chloride (BAK; 0.01% wt/vol) and disodium edetate (EDTA; 0.01% wt/vol) showed maximum permeation, followed by Zymar, BAK (0.01% wt/vol), Gatilox, Gatiquin, and Gate (statistically significant P G .05 compared with control). In vitro titration of the formulations with 0.1N NaOH indicated the presence of a buffer in Zymar (pH 6) and Gate (pH 5.8), which may cause irritation and induce lacrimation, resulting in reduced ocular availability in vivo. Thus, formulation with BAK and EDTA, which is unbuffered, has a better likelihood of being absorbed in vivo. The BAK-EDTA formulation significantly (P G .05) increased the permeation of gatifloxacin through paired excised corneas of goat, sheep, and buffalo, compared with the control formulation. The goat cornea showed the greatest increase in permeation, followed by the sheep and buffalo corneas.

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Section: Introductionmentioning

confidence: 99%

Effect of formulation factors on in vitro transcorneal permeation of gatifloxacin from aqueous drops

Majumdar

2006

AAPS PharmSciTech

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“…It has superior efficacy. Studies have shown that a topical gatifloxacin solution may be effective in prevention of infectious conditions such as conjunctivitis, keratitis, and post-cataract endophthalmitis [12]. Fluconazole (2-(2,4-diflurophenyl)-1,3-bis(1H-1,2,4-triazol-1-yl)propan-2-ol) is a popular antifungal drug belonging to the third generation of azole derivatives.…”

mentioning

confidence: 99%

Studies on the characteristics of drug-loaded gelatin nanoparticles prepared by nanoprecipitation

Lee

Khan

Park

et al. 2011

Bioprocess Biosyst Eng

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The morphology of gelatin nanoparticles loaded with three different drugs (Tizanidine hydrochloride, Gatifloxacin and Fluconazole) and their characteristics of entrapment and release from gelatin nanoparticles were investigated by the analysis on nanoparticle size distribution, SEM and FT-IR in this study. The particles were prepared by nanoprecipitation using water and ethanol as a solvent and a nonsolvent, respectively. The exclusion of a crosslinking agent from the procedure led the system to have an irregularly-shaped morphology. Nonetheless, the uncrosslinked case of Gatifloxacin loading generally led to a more homogeneous population of nanoparticles than the uncrosslinked case of Tizanidine hydrochloride loading. No loading was achieved in the case of Fluconazole, whereas both Tizanidine hydrochloride and Gatifloxacin are observed of being capable of being loaded by nanoprecipitation. Tizanidine hydrochloride-loaded, blank and Gatifloxacin-loaded nanoparticles yielded, under crosslinked condition, 59.3, 23.1 and 10.6% of the used dried mass. The crosslinked Tizanidine hydrochloride-loaded particles showed the loading efficiency of 13.8%, which was decreased to 1.1% without crosslinking. A crosslinker such as glutaraldehyde is indispensable to enhance the Tizanidine hydrochloride-loading efficiency. To the contrary, the Gatifloxacin-loading efficiency for crosslinked ones was lower by a factor of 2-3 times than that for uncrosslinked ones. This is due to the carboxylic groups of Gatifloxacin and the aldehyde groups of glutaraldehyde competing with each other during the crosslinking process, to react with the amino groups of gelatin molecules. The loading efficiency of gelatin nanoparticles reported by other investigators greatly varies. Nevertheless, the loading efficiency reported by us is in good agreement with the drug-loading data of gelatin nanoparticles reported by other investigators. The 80% of loaded Tizanidine hydrochloride was released around 15 h after start-up of the release experiment, while the 20% of loaded Gatifloxacin was released more rapidly, as free Gatifloxacin, than the loaded Tizanidine hydrochloride and it showed the trend of sustained slow release during the remaining period of its release experiment. Furthermore, the result of comparative FT-IR analysis is consistent to that of the corresponding drug release study.

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“…42,43 The percentage of P aeruginosa isolates showing resistance to ciprofloxacin increased from less than 1.0% of isolates obtained from 1991 to 1994 to 4.4% of those obtained from 1995 to 1998 44,45 and to 29% of those obtained from 2002 to 2003. 31 In the same time periods, the rates of resistance to gentamicin increased from less than 1% to 18%. 31,45 31,42 However, coagulase-negative staphylococci isolates from separate studies ending in 2006 identified rates of resistance to gatifloxacin of 11.6% in normal ocular bacterial flora 47 and of 53% in coagulase-negative staphylococci endophthalmitis isolates.…”

Section: Fluoroquinolone Resistance Mechanismsmentioning

confidence: 95%

“…31 In the same time periods, the rates of resistance to gentamicin increased from less than 1% to 18%. 31,45 31,42 However, coagulase-negative staphylococci isolates from separate studies ending in 2006 identified rates of resistance to gatifloxacin of 11.6% in normal ocular bacterial flora 47 and of 53% in coagulase-negative staphylococci endophthalmitis isolates. 48 A study of resistance patterns to ocular coagulase-negative staphylococci isolates in Brazil over a 15-year period found that resistance to gentamicin and tobramycin increased from nothing in conjunctival isolates obtained from 1985 to 1988 to 13% and 11%, respectively, in isolates obtained in 1997 and 2000.…”

Section: Fluoroquinolone Resistance Mechanismsmentioning

confidence: 95%

“…These tests are also useful for ranking the comparative susceptibility of a bacterial pathogen to various antibiotic agents and tracking resistance trends. 31 Nevertheless, data presented by Parmar et al 32 lend some credence to the applicability of CLSI methods for testing ocular isolates. The authors compared in vitro Table 2, there was a significant difference in the percentages of gram-positive cocci, S epidermidis, and S pneumoniae isolates that tested susceptible to gatifloxacin compared with the older fluoroquinolone, ciprofloxacin.…”

Section: Fluoroquinolone Resistance Mechanismsmentioning

confidence: 98%

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Emerging antibiotic resistance in ocular infections and the role of fluoroquinolones

McDonald

Blondeau²

2010

Journal of Cataract and Refractive Surgery

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Resistance to antibiotic agents is becoming increasingly prevalent among ocular infections. Between 19% and 60% of Streptococcus pneumoniae and Staphylococcus aureus isolates have been shown to be resistant to macrolide antibiotic agents, penicillin, and older fluoroquinolones. Although topical fluoroquinolones are considered first-line treatment of ocular infections, as much as 85% of methicillin-resistant S aureus isolates are resistant to ophthalmic fluoroquinolones, including the newer 8-methoxy fluoroquinolones, gatifloxacin and moxifloxacin. Besifloxacin, an 8-chlorofluoroquinolone, has a lower minimum inhibitory concentration against multidrug-resistant staphylococcal strains than other fluoroquinolones and less selective pressure for resistance development because of the lack of a systemic counterpart. In addition to the development of new antibacterial agents, antibiotic resistance in ocular infections may be reduced by following the same strategies used to minimize antimicrobial resistance in systemic infections.

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Comparison of in vitro Susceptibilities of Ocular Bacterial Isolates to Gatifloxacin and Other Topical Antibiotics

Cited by 39 publications

References 42 publications

Effect of formulation factors on in vitro transcorneal permeation of gatifloxacin from aqueous drops

Effect of formulation factors on in vitro transcorneal permeation of gatifloxacin from aqueous drops

Studies on the characteristics of drug-loaded gelatin nanoparticles prepared by nanoprecipitation

Emerging antibiotic resistance in ocular infections and the role of fluoroquinolones

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