• Users Online: 1325
  • Print this page
  • Email this page


 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2018  |  Volume : 4  |  Issue : 1  |  Page : 21-28

Evaluation of the efficacy of topical ofloxacin, pefloxacin, lomefloxacin, sparfloxacin in the experimental model of corneal ulcer


1 Department of Ocular Pharmacology and Pharmacy, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi-110029, India
2 Department of Pharmacology, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi-110029, India
3 Department of Medical Ophthalmology, Retina and Uvea, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi-110029, India
4 Department of Pediatric Ophthalmology and Oculoplasty, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi-110029, India

Date of Web Publication10-Dec-2020

Correspondence Address:
Nihar Ranjan Biswas
Director & Vice-Chancellor, Indira Gandhi Institute of Medical Sciences, Sheikhpura, Patna-800014, Bihar; Department of Pharmacology, All India Institute of Medical Sciences, New Delhi- 110029; Director & Vice-Chancellor, Indira Gandhi Institute of Medical Sciences, Sheikhpura, Patna-800014, Bihar
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


Rights and PermissionsRights and Permissions
  Abstract 


Objective: This study was designed to evaluate the efficacy of topical ofloxacin, pefloxacin, lomefloxacin, sparfloxacin in the experimental model of corneal ulcer.
Methods: Twenty New Zealand albino rabbits of either sex weighing 1.5-2 kg body weight were used for the corneal ulcer efficacy study, Staphylococcus aureus was cultured in 1% peptone water by incubating it at 37? c for 48 hrs. The colony forming unit (CFU) was estimated by using standard McFarland’s tube. Sterile Saline (0.05 ml) containing Staph. Aureus 5x 106 CFU per ml was used for the induction of corneal ulcer. About 10-15μl of the incoculum was injected intrastromally into the peripheral cornea of rabbits using a 1 ml tuberculin syringe fitted with 30G needle. After delivery of inoculums, the epithelial layer was carefully removed by scratching with scalpel blade just above the inoculums delivery site. Before induction of corneal ulcer, all the rabbits were anaesthetized. The antimicrobial therapy was initiated after 18 hrs of the inoculation. 50 μl of formulation were instilled four times a day. Treatment was given up to 4 weeks in each group.
Results: After 14 days of treatment with lomefloxacin and sparfloxacin a significant reduction in ulcer size was recorded in the animals. Where as the same was achieved in 7 days after topical ofloxacin treatment. Based on this observation, the efficacy of the tested formulations can be graded in this following order i.e pefloxacin = nanoparticulated sparfloxacin> sparfloxacin> lomefloxacin> ofloxacin. While comparing the percentage healing that occurred after two weeks of therapy, (using the ulcer size) pefloxacin (0.3%) showed 100% healing.
Conclusion: Efficacy wise pefloxacin was found to be superior as compared to other fluoroquinolones studied.

Keywords: Fluoroquinolones, Efficacy, Staph, aureus


How to cite this article:
Ravi AK, Biswas NR, Velepandian T, Sampangi R, Garg PS, Ghose S. Evaluation of the efficacy of topical ofloxacin, pefloxacin, lomefloxacin, sparfloxacin in the experimental model of corneal ulcer. J Indira Gandhi Inst Med Sci 2018;4:21-8

How to cite this URL:
Ravi AK, Biswas NR, Velepandian T, Sampangi R, Garg PS, Ghose S. Evaluation of the efficacy of topical ofloxacin, pefloxacin, lomefloxacin, sparfloxacin in the experimental model of corneal ulcer. J Indira Gandhi Inst Med Sci [serial online] 2018 [cited 2022 Jan 20];4:21-8. Available from: http://www.jigims.co.in/text.asp?2018/4/1/21/302979




  Introduction : Top


The fluoroquinolones have become widely used antibacterial agents in the treatment of ocular infections, with topical intravitreal and systemic routes of administration being used.

In general fluoroquinolones (such as ciprofloxacin, ofloxacin, lomefloxacin and norfloxacin) have good activity against Gram-negative and Gram-positive bacteria. Therapeutic concentrations are achieved in the cornea after topical administration so that the fluroquinolones have largely replaced combination therapy for the treatment of bacterial keratitis. However, a second line agent is needed when resistance is likely, such as in disease caused by streptococcal species. Reversal of resistance to quinolones may not occur with withdrawl of the antibacterial. This stresses the importance of prudent prescribing to reduce the occurrence of resistance to quinolones. When used in therapeutic topical dosages, corneal toxicity does not occur. Similarly, retinal toxicity is not seen when fluroquninolones are used at therapeutic dosages, systemically or topically. Corneal precipitation occurs, particularly with ciprofloxacin and to a lesser extent norfloxacin, but does not appear to interfere with healing. In the treatment of endophthalmitis there is reasonable penetration of systemic fluoroquinolones into the vitreous humour but sufficiently high concentrations to reach the minimum inhibitory concentration for 90% of isolates (MIC90) of all-important microorganisms may not be guaranteed. Systemic administration is useful for prophylaxis after ocular trauma.

In 1986, Salvanet et al[1]. measured pefloxacin concentrations in the eye. After 1 hr infusion of pefloxacin 400mg I.V. the mean pefloxacin concentrations in aqueous humour 2, 6, 12 and 24 hrs post-infusion were 0.75, 1.45, 1.04 and 0.86 mg/1, respectively and in lens were 0.09, 0.20, 0.26 and 0.43 mg/1, respectively, Similar findings were also observed after repeated oral administration by Salvanet et al[2]. Their results were suggested that aqueous humour concentration 2 hrs after the infusion might reach the MIC 90 for ocular organisms.

In 1987, Behrens-Baumann et al[3] published his study reports on ciprofloxacin concentration in human aqueous humour. Sixteen patients were given an I.V. infusion of 200mg ciprofloxacin 1, 2, 3 and 6 hrs respectively, before cataract extraction. The mean aqueous humour levels were 0.6± 0.09 and 0.12±0.03 μg/ml after 1 and 3 hrs, respectively. The mean serum levels were 1.76±0.87 and 0.85±0.28 μg/ml after 1 and 3 hrs, respectively. These levels were above the MIC90 of ciprofloxacin for sensitive organisms.

The comparative in vitro activity of ofloxacin study was done by Gruneberg et al[4]. Ofloxacin was very active against nalidixic acid-susceptible isolates of Enterobacteriaceae (MIC≤0.12 mg/1) and was active against strains resistant to nalidixic acid (MIC≤mg/1). The activity was similar to norfloxacin. Enoxacin and pefloxacin but some four-fold less than that of ciprofloxacin. Ofloxacin, and all of the fluroquinolones, were less active against anaerobic than aerobic bacteria. Chin et al[5] has studied the in vitro antimicrobial activity of lomefloxacin compared with another fluroquinolones. 90% of Pseudomonas was inhibited by lomefloxacin at 4 μg/ml. Lomefloxacin was equal in activity to norfloxacin against Escherichia coli, Klebsiella spp., Enterobactor spp., Haemophilus influenza and Neisseria gonorrheae but was two folds less active against Proteus spp, Providencia spp, Serratia marcescens, Salmonella spp. and Shigella spp end. Another comparative in vitro activity study of ofloxacin and selected ophthalmic antimicrobial agenst against ocular bacterial isolates were published by Osato et al[6]. Ofloxacub was evaluated against 419 ocular bacterial isolates of 55 species to determine its potential as a topical agent for the treatment of ocular infections. MIC 90 of ofloxacin was 0.5 μg/ml for Staphylococcus aureus and Staphylococcus epidermidis, and 4 μg/ml for Pseudomonas aeruginosa. In another experimental study, reported by Gupta et al[7] showed 0.3% topical norfloxacin drops to be highly effective against pseudomonas induced corneal ulcer in rabbit eye.

Intravitereal penetration of orally administered ciprofloxacin in human was evaluated by keren et al[8]. In their study group, when 14 patients received a single dose of ciprofloxacin orally, drug levels in the vitreous humour were 0.10-0.28 μg/ml; whereas in the seven patients who received two doses of ciprofloxacin, the mean vitreous humour drug level was 0.2-0.9 μg/ml. Their data suggested that oral ciprofloxacin might be used for prophylaxis and possible treatment of bacterial endophthalmitis.

Vajapyee et al[9] reported a clinical trial of topical 0.3% norfloxacin eye drops against Pseudomonas ulcerative keratitis. Excellent response was achieved in all 12 eyes, resulting in complete ulcer cure, In 1991, Cochereau- Massin et al[10] determined the ocular kinetics of pefloxacin when administered by the intramuscular route to albino and pigmented rabbits in an experimental study. In serum of albino rabbits, AUC was 31.4±1.07 μg.hml, the AUC in the aqueous and vitreous and vitreous humours were 10.5±1.90 and 12.4±3.79 μg/hml respectively, pefloxacin in cornea and lens was found 30.15±3.79 μg/hml respectively. In the vascularised tissues, the penetration ratio, defined as tissue AUC/ serum AUC, was more than 1. In pigmented rabbits, pefloxacin levels were high in the iris and chorioretina.

Norfloxacin penetration into the aqueous humour of human eyes of 46 patients was reported by Huber-Spitzy et al[11]. Aqueous humour was sampled at the beginning of surgery and assayed for the level of antibiotic with high performance liquid chromatography (HPLC). Half an hr after administration, mean aqueous humour levels of 255±249 ng/ml were obtained after two drops of 0.3% norfloxacin instillation, however, after five drops instillation, aqueous humour mean was 660.25±378.2 ng/ml. Milter et al[12] reported a rabbit model in which sequential aqueous humour and vitreous humour samples were obtained following the I.V. infusion of the quinolone fleroxacin. The maximum concentration and the penetration into the aqueous humour and vitreous humour were 1.54 & 0.5 μg/ml and 27% & 10% respectively. Based on ocular pharmacokinetic studies they suggested that the fluroquinolone antimircrobial agents might have a role in the prophylaxis and treatment of bacterial endophthalmitis. Bron et al[13] reported clinical as well as experimental study on ocular penetration of topically applied 0.3% norlfloxacin in the rabbit and in the humans. Results were quite similar to those from Ooishi et al[14], which was first pharmacokinetic published study of topically applied 0.3% norfloxacin in the rabbit. In normal eyes, after 30 mins, mean±SEM levels were 14.3±3.7 μg/g in conjunctiva, 0.2±0.1 μg/g in aqueous humour. The intracorneal penetrations were assessed in patients being operated on corneal graft. After instillation of 5 drops, the concentration in cornea was 15.5±2.01 μg/g.

Hobden et al[15] reported a study on ciprofloxacin ointment versus ciprofloxacin drops for therapy of experimental Pseudomonas keratitis. The concentrations of ciprofloxacin in the aqueous humour produced by the drops were significantly higher than the concentrations produced by the ointment.

The comparative study of ocular penetration of topical ciprofloxacin and norfloxacin drops and their effect upon eyelid flora were reported by Leeming at al[16]. The mean aqueous humour concentration s of ciprofloxacin and norfloxacin were 220 ng/ml, 140 ng/ml respectively. This investigation has shown a statistically significant decrease in eyelid flora following six does I hourly drops of ciprofloxacin. In 1994, Donnenfeld et al[17] reported a classical study on ocular penetration of topically applied ciprofloxacin, norfloxacin and ofloxacin into the aqueous humour. Mean aqueous humour ciprofloxacin was 0.72μg/ml.; norfloxacin was 0.06 μg/ml; and ofloxacin levels were 0.338 μg/ml. Topical ofloxacin achieved aqueous humour levels significantly higher than either ciprofloxacin or norfloxacin (p<0.004). There were no statistically significant differences in intraocular aqueous humour levels of ciprofloxacin versus norfloxacin (p>0.05). In 1994, Bron et al[18] studied the ocular penetration of oral sparfloxacin in human in 28 patients undergoing cataract surgery. The mean±SEM level was 0.13±0.04 μg/ml at two hrs; 0.21±0.09 μg/ml at 5 hrs; 0.25±0.04 μg/ml at 8 hrs; 0.39±0.09 μg/ml at 10 hrs; 0.36±0.07 μg/ml at 12 hrs; and 0.04±0.16 μg/ml at 24 hrs.

According to Diamond et al[19], intracorneal concentrations of ofloxacin (0.81 mg/kg) were significantly higher than both ciprofloxacin (0.60 mg/kg) and norfloxacin (0.54 mg/kg). MIC90 of the fluoroquinolones against ocular patheogens reveals that ciprofloxacin is more potent than ofloxacin. Their data suggested the selection of ciprofloxacin and ofloxacin rather than norfloxacin for the treatment of corneal infection.

In 1999, Cekic et al[20] and Beck et al[21] reported ocular penetration of ciprofloxacin, norfloxacin and ofloxacin using different topical modes. Ofloxacin aqueous humour level was found 4 times higher than that of ciprofloxacin and norfloxacin, Comparative studies on topical lomefloxacin and ciprofloxacin on ocular kinetic and experimental corneal ulcer has been evaluated by Velpandian et al[22]. Lomefloxacin showed a better ocular kinetic profile than ciprofloxacin. In corneal ulcer studies, the clinical efficacy of 4 times a day instillation of ciprofloxacin was equivalent to twice a day application of lomefloxacin.

Ozturk et al[23] studied the effect of prolonged acute use and inflammation on the ocular penetration of topical ciprofloxacin. Their results showed that topical 0.3% ciprofloxacin with prolonged use achieved aqueous humour levels above the MIC90 for common ocular pathogens. Higher aqueous humour concentration of ciprofloxacin was obtained with prolonged use and in the pressure of inflammation and also with higher vitreous humour concentration. Small et al[24] developed an easy, fast yet accurate method for tear sampling techniques for ocular pharmacokinetic experimental study of ofloxacin.


  Material & Methods : Top


Materials

Eye Dropos

Oflox 0.3% (ofloxacin) and Proflox 0.3% (perfloxacin) eye drops were gifted by Cipla Ltd, Mumbai (India). Lomibact 0.3% (lomefloxacin and scat 0.3%(sparfloxacin) were gifted by Milmet Pharma Ltd. Baroda (India) and santé vision, Division of Cadila Pharma Ltd., Ahmedabad (India) respectively.


  Rabbits : Top


White albino rabbits weighing 1.5-2 kg body weight were procured from Institute’s Animal House, All India Institute of Medical Sciences, New Delhi after the due approval of Standing Animal Ethics Committee, AIIMS, New Delhi. Rabbits were housed in the departmental animal house, food and water given ad libitum.


  Operating Microscope : Top


Model OM 30U, Takagi, operating microscope was used for grafting of amniotic membrane during in vivo experiment on rabbit eye.


  Methods : Top


Commercial preparations of ofloxacin, pefloxacin, lomefloxacin and sparfloxacin eye drop (0.3%) were used for this study.

3.1 Animals

Twenty New Zealand albino rabbits of either sex weighing 1.5-2 kg body weigh were used for the corneal ulcer efficacy study. Rabbits were procured from the Animal House of All India Institute of Medical Sciences, New Delhi. All animals were treated according to the provisions of the Association for Research in Vision and Ophthalmology (ARVO) resolutions for the usage of animals in ophthalmic research.

3.2 Induction of Corneal Ulcer

Staphylococcus aureus (ATCC strain no 25923) obtained from the Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India. It was cultured in 1% peptone water by incubating it at 37°C for 48 hrs. The colony forming unit (CFU) was estimated by using standard McFarland’s tube. Sterile saline (0.05 ml) containing Staph aureus 5x106 CFU per ml was used for the induction of corneal ulcer. About 10-15 μl of the inoculm was injected intrastromally into the peripheral cornea of rabbits using a 1ml tuberculin syringe fitted with 30G needle. The injection was performed slowly, under the operating microscope with the bevel of the needle facing upward during the insertion into the stromal layer. The face of needle’s bevel was turned down during the delivery of microbes. After delivery of inoculums, the epithelial layer was carefully removed by scratching with scalpel blade just above the inoculums delivery site. Care was taken to avoid entering of microbes into the anterior chamber of the eye. Before induction of corneal ulcer, all the rabbits were anaesthetized with sodium petobarbitone intravenous bolus dose of 30 mg/kg body weight, Cornea was anaesthetized with 4% xylocaine before performing the intra-stromal delivery of inoculum. Only one eye of each rabbit was used for this study to avoid any possible complete blindness of rabbits after induction of corneal ulcer.

3.3 Drug Treatment

The antimicrobial therapy was initiated after 18 hrs of the inoculation. The rabbits, which were having at least grade I ulcer, were included in the study. Rabbits were divided into five drug groups having four each. Group-I received 50μl of commercial preparation of 0.3%w/v pefloxacin; Group-II received 50 μl of commercial preparation of 0.3% w/v pefloxacin; Group-III received 50 μl of commercial preparation of 0.3%w/v lomefloxacin; Group-IV received 50μl of commercial preparation of 0.3%w/v sparfloxacin; Group-V received 50 μl of 0.1%w/v nanoparticulated sparfloxacin (equivalent to 0.1% sparfloxacin) formulation four times a day (QID). All formulations were instilled at the volume of 50μl with the help of a calibrated micropipette. Treatment was given up to 4 weeks in each group.

3.4 Assessment of Corneal Ulcer

The pathological signs developed in the anterior segment were assessed using the slit lamp biomicroscope. To establish an objective evaluation of lesions, the corneal ulcer was graded as described by Mohan et al. (1984) on a five-point scale:

Grade 0 : Normal transparent cornea/with scar

Grade I : Ulcer less than 2 mm

Grade II : Ulcer up to 4 mm

Grade III : Ulcer up to 6 mm

Grade IV : Ulcer extending up to 10 mm

Grade V : Ulcer involving total cornea and extending into cornea

The state of lid edema, conjunctival congestion, discharge, superficial neovascularisation and hypopyon were assessed using the following scale:

0: Absent +: Mild, ++: Moderated, +++: Severe

Statistical Analysis

For the efficiacy studies in the model of experimental corneal ulcer, one way analysis of variance (ANOVA) with repeated measures was used.


  Results : Top


Ofloxacin Efficiacy Study in the Rabbit Model of Corneal Ulcer

Corneal ulcer was induced by injecting sterile saline (0.05 ml) containing live Staphylococcus aureus at the concentration of 5x106 CFU/ml instrastromally under anaesthesia. Eighteen hours after the inoculation, the ulcer reached the mean size of 3.9±1.03mm (with a mean grading of 2.7±0.5). After the initiation of topical ofloxain 0.3% eye drop 4 times a day, the ulcer contained and started regressing. The overall decrease in ulcer size over the period of 4 weeks was found to be statistically significant (p<0.01). After 7 days of topical ofloxacin treatment, the decrease in corneal ulcer size was found to be statistically significant (p<0.05)[Figure 1] Hoever, by applying the corneal grading system a statistically significant decrease was observed only 14 days after the inititatiopn of the treatment as com pared to the baseline values [Figure 2] The overall decrease in ulcer size over the period of 4 weeks was found to be statistically significant (p<0.01) [Figure 1].
Figure 1

Click here to view
Figure 2

Click here to view


Assessing associated symptoms like discharge with four-point scale showed a mean scoring from moderate to severe (2.7±0.5) on day 0. One week after the treatment the discharge was significantly decreased to 1.2±0.5. After 14 days of therapy, the discharge was disappeared [Figure 3].
Figure 3

Click here to view


Lid edema showed a severity scale of 1.25±0.5 on day 0. However, after one week treatment the severity was decreased and disappeared upon 2 weeks of therapy [Figure 4] similarly, conjunctival congestion was reduced significantly as compared to day 0 value (3.12±0.25 vs 1.7±0.5) After 4 weeks, it was totally disappeared [Figure 5].
Figure 4

Click here to view
Figure 5

Click here to view


Appearance of hypopyon was observed to the maximum of 3±0.8 on day 7. After 3 weeks of therapy, it was tottaly disappeared [Figure 6]. Corneal neovascularisation as a secondary complication of corneal infection was seen in this model. A maximum score of 2.2±0.5 was seen on a day 7. However, after continuing the treatment till day 14 a significant reduction was observed [Figure 7].
Figure 6

Click here to view
Figure 7

Click here to view


Pefloxacin Efficacy Study in the Rabbit Model of Corneal Ulcer

In the pefloxacin treated group, 18 hrs after the inoculation, the ulcer reached the mean size of 3.0±0.7 mm (with a mean grading of 1.75±0.5). After the in ititation of topical pefloxacin 0.3%eye drop four times a day the corneal ulcer started regressing. The overall decrease in ulcer size over the period of 4 weeks was found to be statistically significant (p<0.01). After 14 days of topical pefloxacin treatment, the decrease in corneal ulcer size as well as ulcer grading were found to be statistically significant as compared to the baseline values [Figure 1],[Figure 2].

Evaluating associated symptoms like discharge with four-point scale showed a mean scoring from moderate to severe (2.2±0.5) on day 0. One week of pefloxacin treatment significantly (p<0.05) decreased the discharge to 0.5±0.5. After 14 days of therapy, the discharge was disappeared completely [Figure 3]

Lid edema showed a severity scale of 1 on day 0. However, after 1 week treatment the same grade of lid edema was sustained and disappeared upon 2 weeks of therapy [Figure 4]. Similarly, conjunctival congestion was reduced significantly on day 14 after the treatment as compared to day 0 value (1.3±0.5 vs 3.0). After 4 weeks, it was tottaly disappeared [Figure 5].

Appearance of hyupopyon was observed to the maximum of 2±0.8 on the day 0. After two weeks of therapy, it was tottaly disappeared [Figure 6]. Corneal neovascularisation as a secondary complication of corneal infection was seen in this model. A maximum score of 2.5±0.6 was seen on the day 14. However, after continuing the treatment till day 28, a significant reduction (p<0.05) was observed [Figure 7].

Lomefloxacin efficacy study in the rabbit model of corneal ulcer

In the lomefloxacin 0.3% treated group, 18 hrs after the inoculation, the ulcer reached the mean size of 2.5±0.4 mm (with a mean grading of 1.8±0.5). After the initiation of topical lomefloxacin 0.3% eye drop four times a day, the corneal ulcer started regressing. The overall decrease in ulcer size over the period of 2 weeks was found to be statistically significant (p=0.021). After 14 days of topical lomefloxacin treatment the decrease in corneal ulcer size was found to be statistically significant (p<0.05) [Figure 1].

However, by applying the corneal grading system a statistically significant decrease was observed only 21 days after the initiation of treatment as compared to the baseline values [Figure 2].

Evaluating associated symptoms like discharge with four-point scale showed a mean scoring of 1 on the day 0. One week of lomefloxacin caused disappearance of the discharge [Figure 3].

Lid edema showed a severity scale less than 1 on the day 0. However, after 1 week treatment the severity was disappeared [Figure 4].

Conjunctival congestion was reduced significantly on day 7 after the treatment as compared to day 0 value (1.53±0.6 vs 2.5±0.6). After 3 weeks, it was totally disappeared [Figure 5].

Appearance of hypopyon to a mild degree was observed on the day 0. After two weeks of therapy, it was totally disappeared [Figure 6].

Corneal neovascularisation as a secondary complication of corneal infection was seen in this model. A maxium score of 2±0 was seen on day 7. However, after continuing the treatment till day 14 a significant reduction (p<0.05) was observed [Figure 7].

Sparfloxacin efficacy study in the rabbit model of corneal ulcer.

In the sparfloxacin treated group of 18 hrs after the inoculation the ulcer reached the mean size of 4.1±1.4 mm (with a mean grading of 2.25±0.9). After the initiation of topical sparfloxacin 0.3% eye drop four times a day the corneal ulcer started regressing. The overall decrease in ulcer size over the period of three weeks was found to be statistically significant (p<0.01). After 14 days of topical sparfloxacin treatment, the decrease in corneal ulcer size was found to be statistically significant (p<0.05)[Figure 1]. Applying the corneal grading system also showed a stastically significant decerease on day 14 evaluations after the initiation for the treatment as compared to the baseline values [Figure 2].

Evaluating associated symptoms like discharge with a four point scale showed a mean scoring from moderate to severe (2.0±0.8) on day 0. After one week of sparfloxacin treatment significantly decreased the discharge to 0.5±0.58. After 14 days of therapy, the discharge was disappeared [Figure 3].

Lid edema showed a severity scale of 1.25±0.5 on the day 0. However, after 1 week treatment, the severity was decreased and disappeared upon 2 weeks of therapy [Figure. 4]. Similarly, conjunctival congestion was reduced significantly on day 14 after the treatment as compared to day 0 value (0.9±0.8 vs 2.2±0.5). After 3 weeks it was totally disappeared [Figure 5].

Appearance of hypopyon was observed to the maximum of 3±0.8 on the day 1. After two weeks of therapy, it was totally disappeared [Figure 6].Corneal neovascularisation as a secondary complication of corneal infection was seen in this model. A maximum score of 2.2±0.5 was seen on day 7. However, after continuing the therapy further a significant (p<0.05) reduction was observed on day 14 [Figure 7].




  Discussion : Top


Fluoroquinolones are a class of synthetic antibacterial agents that were approved for ocular therapy in 1991. Ever since they have been used as a popular therapy for the treatment and prevention of various ocular infections [Anderson et al[25]]. Presently, fluoroquinolones have been widely used as an antibacterial agent with topical, intravitereal and systemic routes of administration. These agents are synthetic, with broad-spectrum of activity, rapidly bactericidal, and good penetration into ocular tissues [Stroman et al[26])]. In general, fluroquinolones such as norfloxacin, ciprofloxacin, ofloxacin, and lomefloxacin etc. Have good activity against Gram-negative and Gram-positive bacteria. Therapy with fluroquinolones has largely replaced the combination therapy for mainly ocular infections e.g. bacterial keratitis as the therapeutic concentrations are well achieved in the cornea after topical administration. These agents are not reported to cause corneal toxicity or retinal toxicity when used in therapeutic topical or systemic dosages. Corneal precipitation occurs, particularly with ciprofloxacin and to a lesser extent norfloxacin, but does not appear to interfere with healing of epithelium. In treatment for endophthalmitis, there is a reasonable penetration of systemic fluroquinolones into the vitreous humour but sufficiently high concentrations to reach the minimum inhibitory concentration for 90% of isolates (MIC90) of all important micro-organisms may not be guaranteed. Systemic administration is useful for prophylaxis after ocular trauma. Still, it not sure that how much of systemically given fluoroquinoles would be reaching in intraocular fluids for the treatment of endopthamitis. Several studies reported the individual ocular pharmacokinetics of topically, subconjunctivally, systemically administered fluroquinolones. However, due to the difference in the clinical set up and protocol used for these studies, it is very difficult to compare their ocular pharmacokinetic and pharmacodynamic together. Therefore, a constant desire has been felt to evaluate and compare the commonly used fluroquinolones for their ocular pharmacokinetics and pharmacodynamic together. Therefore, a constant desire has been felt to evaluate and compare the commonly used fluroquinolones for their ocular penetration after oral, topical and intravenous modes of administration. Thus in this purview, the present study was planned to compare the pharmacokinetics profile with pharmacodynamics effects of commonly used ocular fluroquinolones. This would definitely help to compare and evaluate the safety and efficacy of these agents by in vitro, in vivo and clinical settings.

Rabbit model was selected for experimental corneal ulcer study to compare the efficacy of topical ofloxacin, pefloxacin, lomefloxacin, sparfloxacin and nanoparticulated sparfloxacin. The adequate corneal thickness, higher corneal surface area is the chief advantages of using rabbits for this experiment. In the experiment, no control animals were used as per the Institutional Animal Ethics Committee, AIIMS, we cannot leave any animal without treatment. Thus, to save animals from distress and pain due to corneal infection the control group was avoided. Upon corneal inoculation with Staphylococcus aureus (ATCC strain no. 25923) showed grade 1 ulcer within 1-2 days after inoculation. All the animals received four times a day fluoroquinolone topical for the period of four weeks. However, all associated lesions like discharge, lid edema, conjunctival congestion, corneal neovascularisation and hypopyon were reaching different points in the severity scale when fluoroquinolone treatment was initiated.

From our studies, it is evident that experimentally induced corneal ulcer in the rabbit cornea responded well for all fluoroquniolones subjected for comparative evaluation that includes even nanoparticulated formulation of sparfloxacin. After the treatment for two weeks, statistically significant difference in ulcer grading was observed in ofloxacin, pefloxacin and sparfloxacin treated groups, however, it was found only three weeks after lomefloxacin treatment. Ulcer size was shown statistically significant in pefloxacin, lomefloxacin (p<0.05) and sparfloxacin (p<0.05) just after 14 days of topical treatment. But, after 7 days of topical ofloxacin treatment the decrease in corneal ulcer size was found to be stastically significant (p<0.05). while comparing the percentage healing occurred after two weeks of therapy (using the ulcer size) with pefloxacin (0.3%) and nanoparticulated sparfloxacin (0.3% sparfloxacin), both of the fluroquinolones showed 100% healing from day 0 values. Where as, sparfloxacin showed second highest healing rate of 87% lomefloxacin and olfoxacin shoed 42% and 38% healing respectively on day 14 as compared to day 0 values. In this model pefloxacin was found to be effective as compared to other fluroquinolones studied in healing corenal ulcer. Based on this observation the efficacy of the tested formulations can be graded in this following order i.e. pefloxacin= nanoparticulated sparfloxacin> sparfloxacin> lomefloxacin>ofloxacin.

Extrapolating this value to 0.3% reached much higher values as compared to the reported values of Satia et al[27]. This could be due to the use of 1.9% boric acid was used as a vehicle rather than using co-solvents for the solvents for the solubilisation of sparfloxacin in the formulation available for commercial use in India. Vyas et al[28] evaluated the efficacy of sparfloxacin (0.3%) in consecutive culture proven cases of conjunctivitis and corneal infection. They have reported that sparfloxacin 0.3% eye drop provides 100% cure rate clinically as well as bacteriologically. This can be due to better ocular penetration and higher therapeutic index of sparfloxacin 0.3% eye drop. in the present.


  Conclusion : Top


From our studies, it is evident that experimentally induced corneal ulcer in the rabbit cornea responded well for all four fluoroquniolones subjected for comparative evaluation that includes even nanoparticulated formulation of sparfloxacin. Efficacy wise pefloxacin was found to be superior as compared to other fluoroquinolones studied.



 
  References Top

1.
Salvanet A, Fisch A, Lafaix C, Montay G, Dubayle P, Forestier F, Haroche G. Pefloxacin concentrations in human aqueous humour and lens. J Antimicrob Chemother 1986;18(2):199-201.  Back to cited text no. 1
    
2.
Salvanet-Bouccara A, Montay G, Fisch A, Forestier F, Meziane D, Lafaix C, Prieur MB. Diffusion of pefloxacin in the aqueous humour and crystalline lens after repeated oral administration in man. J Fr Ophtalmol 1991;14(4):260-4.  Back to cited text no. 2
    
3.
Behrens-Baumann W, Martell J. Ciprofloxacin concentrations in human aqueous humour following intravenous administration. Chemotherapy 1987;33(5):328-30.  Back to cited text no. 3
    
4.
Gruneberg RN, Felmingham D, O’Hare MD, Robbins MJ, Perry K, Wall RA, Ridgway GL. The comparative in-vitro activity of ofloxacin. J Antimicrob Chemother 1988;22C:9-19.  Back to cited text no. 4
    
5.
Chin N-X, Novelli A, Neu HC. In vitro activity of lomefloxacin (SC- 47111; NY198), a difluoroquinolone 3-carboxylic acid, compared with those of other quinolone. Antimicrob Agents Chemother 1988;656-62.  Back to cited text no. 5
    
6.
Osato MS, Jensen HG, Trousdale MD, Bosso JA, Borrmann LR, Frank J, Akers P. The comparative in vitro activity of ofloxacin and selected ophthalmic antimicrobial agents against ocular bacterial isolates. Am J Ophthalmol 1989;108:380-6.  Back to cited text no. 6
    
7.
Gupta SK, Joshi S, Zingan S. Topical norfloxacin for the treatment of Pseudomonas corneal ulcers - An experimental study. Med Sci Res 1989;17:767-70.  Back to cited text no. 7
    
8.
Keren G, Alphalel A, Bortov, Kirzes-Cohen R, Rubinstein E, Segev S, Treisfer G. The intravitreal penetration of orally administred ciprofloxacin in humans. Invest Ophthalmal Visual Sci 1991;32(8):2388-92.  Back to cited text no. 8
    
9.
Vajpayee RB, Gupta SK, Angra SK, Munjal A. Topical norfloxacin therapy in Pseudomonas corneal ulceration. Cornea 1991;10(3):268-71.  Back to cited text no. 9
    
10.
Cochereau-Massin I, Bauchet J, Marrakchi-Benjaafar S, Saleh-Mghir A, Faurisson F, Vallois JM, Vallee E, Pocidalo JJ. Efficacy and ocular penetration of sparfloxacin in experimental streptococcal endophthalmitis. Antimicrob Agents Chemother 1993;37(4):633-6.  Back to cited text no. 10
    
11.
Huber-Spitzy VN, Czejka M, Georgiew L, Arocker-Mettinger E, Grabner G. Penetration of norfloxacin into the aqueous humour of the human eye. Invest Ophthalmol Vis Sci 1992;33(5):1723-6.  Back to cited text no. 11
    
12.
Miller MH, Madu A, Samathanam G, Rush O, Madu CN, Mathisson K, Mayers M. Fleroxacin pharmacokinetics in aqueous humour and, vitreous humour determined by using complete concentration-time data from individual rabbits. Antimicrob Agents Chemother 1992;36:32-8.  Back to cited text no. 12
    
13.
Bron AM, Pechinot A, Garcher C, Guyonnet G, Kazmierczak A. Ocular penetration of topically applied norfloxacin 0.3% in the rabbits and in humans. J Ocul Pharmacol 1992;8:241-6.  Back to cited text no. 13
    
14.
Ooishi M, Oomomo A, Sakaue F, Tazawa H. Studies on NFLX levels in the cul-de-sac and intraocular penetration of NFLX eye drops. Nippon Ganka Gakkai Zasshi (Acta Soc Ophthalmol Jpn) 1987;91(1):161-7.  Back to cited text no. 14
    
15.
Hobden JA, O’Callaghan RJ, Insler MS, Hill JM. Ciprofloxacin ointment versus ciprofloxacin drops for therapy of experimental Pseudomonas keratitis. Cornea 1993;12(2):138-41.  Back to cited text no. 15
    
16.
Leeming JP, Diamond JP, Trigg R, White L, Hoh HB, Easty DL. Ocular penetration of topical ciprofloxacin and norfloxacin drops and their effect upon eyelid flora. Br J Ophthalmol 1994;78:545-8.  Back to cited text no. 16
    
17.
Donnenfeld ED, Schrier A, Perry HD, Aulicino T, Gombert ME, Snyder R. enetration of topically applied ciprofloxacin, norfloxacin, and ofloxacin into the aqueous humour. Ophthalmology 1994;101(5):902-5.  Back to cited text no. 17
    
18.
Bron AM, Pechinot AP, Garcher CP, Guyonnet GA, Kazmierczak AM, Schott DA, Lecoeur H. The ocular penetration of oral sparfloxacin in humans. Am J Ophthalmol 1994;117(3):322-7.  Back to cited text no. 18
    
19.
Diamond JP, White L, Leeming JP, Hoh HB, Easty DL. Topical 0.3% ciprofloxacin, norfloxacin, and ofloxacin in treatment of bacterial keratitis: a new method for comparative evaluation of ocular drug penetration. Br J Ophthalmol 1995;79:606-9.  Back to cited text no. 19
    
20.
Cekic O, Batman C, Totan Y, Yasar U, Basci NE, Bozkurt A, Kayaalp SO, Zilelioglu O. Aqueous humour levels of topically applied ciprofloxacin and ofloxacin in the same subjects. Eye 1999;13(5):65- 9.  Back to cited text no. 20
    
21.
Beck R, van Keyserlingk J, Fischer U, Guthoff R, Drewelow B. Penetration of ciprofloxacin, norfloxacin and ofloxacin into the aqueous humour using different topical application modes. Graefes Arch Clin Exp Ophthalmol 1999;237(2):89-92.  Back to cited text no. 21
    
22.
Velpandian T, Gupta SK, Gupta YK, Agarwal HC, Biswas NR. Comparative studies on topical lomefloxacin and ciprofloxacin on ocular kinetic and experimental corneal ulcer. J Ocul Pharmacol Ther 1999;15(6):505-11.  Back to cited text no. 22
    
23.
Ozturk F, Kurt E, Inan OO, Kortunay S, IIker SS, Basci NE, Bozkurt A. The effects of prolonged acute use and inflammation on the ocular penetration of topical ciprofloxacin. Int J Pharm 2000;204:97-100.  Back to cited text no. 23
    
24.
Small D, Hevy J, Tang-Liu D. Comparative of tear sampling techniques for pharmacokinetic analysis: Ofloxacin concentrations in rabbit tears after sampling with Schirmer’s tear strips, capillary tubes, or surgical sponges. J Ocul Pharmacol Ther 2000;16(5):439-46.  Back to cited text no. 24
    
25.
Andersson MI, MacGowan AP. Development of the quinolones. J Antimicrob hemother 2003;51(1):1-11.  Back to cited text no. 25
    
26.
Stroman DW, Dajcs JJ, Cupp GA, Schlech BA. In vitro and in vivo potency of moxifloxacin and moxifloxacin ophthalmic solution 0.5%, a new topical fluoroquinolone. Surv Ophthalmol 2005;50(1):S16-31.  Back to cited text no. 26
    
27.
Satia MC, Mody VD, Modi RI, Kabra PK, Khamar M. Pharmacokinetics of topically applied sparfloxacin in rabbits. Indian J Ophthalmol 2005;53(3):177-81.  Back to cited text no. 27
    
28.
Vyas U, Desai T, Shah C. Evaluation of sparfloxacin eye drop in the management of conjunctival and corneal infection. J Indian Med Assoc 2002;100(6):398-9.  Back to cited text no. 28
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction :
Material & M...
Rabbits :
Operating Micros...
Methods :
Results :
Discussion :
Conclusion :
References
Article Figures

 Article Access Statistics
    Viewed833    
    Printed20    
    Emailed0    
    PDF Downloaded31    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]