DESC:
TITLE OF THE INVENTION
Implantable sustained release antimicrobial disc for corneal infections and abscesses.

FIELD OF THE INVENTION
The present invention relates to a novel implantable antimicrobial disc for treatment of corneal infection more preferably posterior corneal infection and abscesses. The present invention also refers to a method for preparation of novel implantable antimicrobial disc. Further, the present invention also relates to a method for the treatment of corneal infection using a novel implantable antimicrobial disc.

BACKGROUND OF THE INVENTION
A corneal infection is an infection of the transparent section in front of the eyeball that allows light into the eye. A corneal infection, or keratitis, occurs when the cornea is damaged by a foreign object, or from bacteria or fungi or parasites acanthamoeba & microsporidia or viruses such as herpes simplex. It can cause painful inflammation and can lead to corneal scarring. In the more severe cases, keratitis can cause blindness.
Currently available methods for the treatment of corneal infections are
a) Topical antimicrobials
b) Parenteral antimicrobials
c) Intrastromal antimicrobial injections
d) Collagen shields mixed with antimicrobial like therapeutic contact lenses

There are certain disadvantages of currently available methods. Topical antimicrobials do not reach effective concentrations in deep corneal tissues. The intrastromal antimicrobial injection could not achieve a long-term concentration of the drug (short half-life and eliminated fast), and there is a risk of corneal perforation while injecting the drug. Further intravenous antimicrobials do not achieve the high concentration in the cornea.
Collagen shields mixed with antimicrobials used as therapeutic contact lenses have higher bioavailability. However, it is like topical administration and concentrations does not reach deeper corneal tissues as they are applied only to the surface.
So, there is a need to develop methods and materials for treatment of deep corneal infections and abscesses with increase efficacy and reduce surface toxicities due to frequent topical administrations.
The inventors of the present invention solved the problem of inefficiencies of current methods for the treatment of corneal infection more preferably posterior corneal infection and abscesses.

OBJECTIVES OF THE INVENTION

The main aim of the invention is to use of novel antimicrobial disc which will have an effective concentration of antimicrobial agent in deeper corneal structures for longer duration of action. Another objective of the invention is to reduce the surface toxicities due to excess topical therapy.

SUMMARY OF THE INVENTION

The present invention relates to novel implantable antimicrobial disc. The novel implantable antimicrobial disc comprises antimicrobial agents.

The present invention relates to novel sustained release implantable antimicrobial disc comprises antimicrobial agents.

The present invention relates to the process for the preparation of implantable antimicrobial disc comprises antimicrobial agent.
The present invention relates to use of implantable antimicrobial disc for the treatment of the corneal infection.

The present invention relates to use of implantable antimicrobial disc for the treatment of the corneal infection more preferably posterior corneal infection and abscesses.

The present invention relates to use of sustained release implantable antimicrobial disc for the treatment of the corneal infection more preferably posterior corneal infection and abscesses.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 01: Intra operative pictures of intracorneal Moxifloxacin disc implantation.
Figure 02: Clinical photos for the posterior Bacterial corneal infection with abscess (02A, 02B: Clinical pictures, 02C: Corneal OCT).
Figure 03: Clinical photos for the treatment with Moxifloxacin disc (03A: Post Moxifloxacin implant day 1, 03B: Post disc removal day 3, 03C, 03D: Post disc removal day 7.
Figure 04: Posterior fungal corneal Infection with abscess (04A, 04B, 04C: Clinical Pictures, D: Corneal OCT)
Figure 05: Intra operative pictures of Amphotericin B implantation (05A and 05B).
Figure 06: Clinical photos (06A, 06B) for the treatment of fungal posterior corneal infection with Amphotericin B disc on day 3 after Amphotericin B disc removal.
Figure 07: Clinical photos (07A, 07B and 07C) for the treatment of fungal posterior corneal infection with Amphotericin B disc on day 7 after Amphotericin B disc removal.
Figure 08: Method for the treatment of a Nocardial infection. (08A: Intra operative pictures of intracorneal Amikacin disc implantation. 08B: Clinical photos for the treatment of Nocardial infection with Amikacin disc on day 14 after removal of Amikacin disc)
Figure 09: Method for the treatment of a case who underwent therapeutic deep anterior lamellar keratoplasty (DALK) (09A: Clinical photos for the pre-operative posterior corneal infection 09B, 09C: Deep anterior lamellar keratectomy 09D: Moxifloxacin B disc placed in the interface during therapeutic deep anterior lamellar keratoplasty).
Figure 10: Clinical photos for the treatment of bacterial infection that underwent therapeutic deep anterior lamellar keratoplasty (10A treatment on day 3 after removal of Moxifloxacin disc and 10B treatment on 14 days on the transplant)
Figure11: Method for the treatment of infected keratoplasty
(11A: Clinical photos for the segmental infection in a post keratoplasty, 11B: Intra Operative pictures of intracorneal Amikacin disc implantation, 11C: Clinical photos for the treatment of infected keratoplasty case after implantation of the Amikacin Disc, 11D: Clinical photos for the treatment of infected keratoplasty case after Amikacin disc infection in day 14)

DETAILED DESCRIPTION OF THE INVENTION

The inventors of the present invention has discovered a novel implantable antimicrobial disc for the treatment of corneal infection more preferable deep corneal infection and abscesses.

One of the aspects of the present invention provides a novel implantable antimicrobial disc comprising antimicrobial agents.

In another aspect, the present invention provides a novel sustained release implantable disc comprising antimicrobial agents.

The present invention further provides a novel implantable antimicrobial disc for the treatment of deep corneal infections and abscesses with reduced surface toxicities.

As used herein, the term "Antimicrobial disc" comprises a wafer of desired size and shape comprising antimicrobial agent. The size and shape of the antimicrobial disc depend upon the severity of corneal infections.

As used herein, the term “Wafer” comprises composition for intra corneal drug delivery comprising antimicrobial agent which implanted at the site of infection that provides targeted delivery of the appropriate therapeutic compounds.

As used herein, the term “Sustained release” is novel targeted drug delivery system to release a drug slowly in order to maintain a constant drug concentration at site of action for a specific period of time with minimum side effects.

In one of the aspect, present invention provides a novel implantable antimicrobial disc wherein antimicrobial disc is thin wafer containing antimicrobial agents.

Whatman® filter paper of suitable grades i.e. grade 1-6, more preferably Whatman® filter paper grade 3 is used for the preparation of wafer. Whatman® filter papers are manufactured from high-quality cotton linters which have been treated to achieve a minimum alpha cellulose content of 98%. These cellulose filter papers are used for general filtration and exhibit particle retention levels down to 2.5 µm. The different groups of filter paper types offer increasing degrees of purity, hardness and chemical resistance.

The inventors of the present invention have found theses Whatman® filter papers are useful for the preparation of the disc because of its high wet strength and water absorbency. The Whatman® papers are durable and easily available to make them best candidate for the preparation of disc which can be implantable in the deep corneal tissues for the treatment of corneal infections.

The shape of wafer used for the preparation of disc is of any shapes most preferably rectangular or circular shape. The size and shape of the wafer further depend upon the severity of corneal infections. The wafers of desired size and shape are prepared by manually or using office punches. Office hole punching machine is used for preparation of circular wafer of approximately 6mm diameter. The wafers are further sterilised by autoclave method at 15lbs pressure for 30 minutes.

The antimicrobial agents referred herein comprise suitable antimicrobial agents those conventionally known in the art for the treatment of corneal infections.

Antimicrobial agents are selected from group comprising antibacterial agents, antifungal agents, the antiparasitic agent, antiviral agents or combination thereof. More preferably antimicrobial agents are selected but not limited to Moxifloxacin, Amikacin and Amphotericin B.

In yet another aspect, the present invention provides a process for preparation of novel implantable disc which comprises,
a) preparing wafer of desired size and shape;
b) impregnating the wafer of step a) to antimicrobial agents for suitable time; and
c) optionally maintaining the dose of the antimicrobial agent as required.

The antimicrobial agent as specified in step b) is in liquid solution form which is prepared by dissolving antimicrobial agent (drug powder) and optionally pharmaceutically acceptable excipients in vehicle to obtain working solution.

Excipients as referred herein include, but are not limited to buffers, preservatives, antioxidants, chelating agents, surfactants, tonicity agent, and polymers. All excipients can be used at levels well known to the persons skilled in the art.

Buffers or buffering agents are selected from the group comprising, borate buffer, phosphate buffer, carbonate buffer, acetate buffer, citrate buffer, e-aminocapronic acid, glutamic acid and salts thereof, and aspartic acid and salts thereof.

Preservative agents are selected from the group comprising, benzalkonium chloride, perborates, percarbonates, benzyl alcohol, chlorbutanol, hydrogen peroxide, polyquarterium, stabilized chlorine dioxide (SCD), boric acid, sorbic acid, potassium sorbate, and mixtures thereof.

Chelating agents are selected from the group comprising, EDTA, cyclohexanediamine tetraacetic acid (CDTA), hydroxyethylethylenediamine triacetic acid (HEDTA), diethylenetriamine pentaacetic acid (DTPA), dimercaptopropane sulfonic acid (DMPS), dimercaptosuccinic acid (DMSA), aminotrimethylene phosphonic acid (ATPA), citric acid and mixtures thereof.

Antioxidant agents selected from the group comprising, sodium metabisulfite, sodium bisulfite, acetylcysteine, sodium thiosulfate and thiourea and mixtures thereof.

Surfactants are selected from the group comprising, polysorbate 80 polysorbate 60, polysorbate 40 [poly(oxyethylene)sorbitan monopalmitate], polyoxyl 40 stearate polyoxyethylene hydrogenated castor oils such as polyoxyethylene hydrogenated castor oil alkyl dimethylaminoacetic acid betaine, fatty acid amide propyldimethylaminoacetic acid betaine, and polyalkylaminoethyl glycine and mixtures thereof.

Tonicity agents are selected from the group comprising, sodium chloride, potassium chloride, potassium sulfates, sodium and potassium bicarbonates, alkaline earth metal salts, mannitol, dextrose, glycerin, propylene glycol, and mixtures thereof.

Polymers are selected from the group comprising, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropylmethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, dextran, chondroitin sulfate and salts thereof, and hyaluronic acid and salts thereof.

Vehicle is selected from but is not limited the aqueous vehicle, hydro alcoholic vehicle. More preferably vehicle is sterile water for injection.

Antimicrobial discs are prepared by loading working solution comprising antimicrobial agent on wafers and keep these disc for 5 to 10 minutes at room temperature. The discs were allowed to dry in a clean incubator at 37°C for 4 hours.

The amount of antimicrobial agent working solution used in preparation of disc is 10 µl to 50µl. Wafer of Whatman® 3 filter paper disc of 6mm diameter can absorb 20µl of solutions.

In yet another aspect, the present invention further provides a use of implantable antimicrobial disc for the treatment of corneal infection more preferably posterior corneal infection and abscesses comprises,
a) diagnosing the corneal infection with using diagnostic methods;
b) providing a stromal bed with 1-2 incision either manually or using femtosecond Lasers;
c) positioning of the implantable antimicrobial disc in incised place for several days;
d) removal of an implantable antimicrobial disc;
e) optionally re-implant the implantable antimicrobial disc if infection is not completely resolved.

Diagnostic methods as referred herein are convention method for diagnosing the corneal infection more preferably Anterior segment- Optical coherence tomography (AS-OCT) for depth for corneal involvement and outcomes.

The antimicrobial discs are implanted at deeper corneal plane of the eye where infections are located. The implantable antimicrobial disc is placed in incised part for several days depending on the severity of infection. Generally disc is placed in incised part for 3 to 5 days. The results of the treatment of the present invention are analyzed using AS-OCT and slit lamp photography.

Following examples are provided for illustration and should not be considered as limiting the scope of the invention.

EXAMPLES

Example 1: Preparation of Moxifloxacin Disc
1) Whatman® 3 filter paper grade 3 was punched using punching machine of approximately 6 mm diameter.
2) Wafers were straightened by keeping them onto a flat surface and applying pressure on them.
3) The wafers were then autoclaved at 15lbs pressure for 30 minutes.
4) Moxifloxacin Hydrochloride 5.45 mg (Equivalent to 5.0 mg of Moxifloxacin base), Boric acid 3.0 mg and Sodium Chloride 6.3 mg were dissolved in sterile water for injection under stirring. pH of the solution was adjusted to 6.7 to 6.9 by adding HCl /NaOH under stirring. The final volume was made up to 1 ml with sterile water for injection.
5) In sterile environment, using a mechanical pipette, a fixed volume of 20µl Moxifloxacin solution (as prepared in step 4) was loaded on whatman 3 filter paper wafer, taking precautions that the tip was in slight contact with the wafer. Kept them for room temperature for 5 to 10 minutes.
6) The discs were allowed to dry in a clean incubator at 37°C for 4 hours. After drying, 30-35 discs were placed in small sterile air-tight labeled containers with CaCl2 (desiccant) at the bottom.

Example 2: Method for the treatment of a bacterial posterior corneal infection
1) A deeper corneal plane was fashioned manually with 1-2 incisions.
2) Moxifloxacin disc (0.5% w/v) as prepared in example 1 was positioned in incised part for five days. Intra operative pictures of intra corneal Moxifloxacin disc implantation are shown in figure 01.
3) The implantable disc was removed after five days and results were analyzed by AS-OCT and slit lamp Photography.

Studies were conducted on 5 patients with the posterior bacterial corneal infection. Posterior bacterial corneal Infection with abscess is shown in figure 02.
Figure 03 represented the post operative results and clinical photos of treatment of bacterial corneal infection with Moxifloxacin disc.
Figure 03A represented Moxifloxacin disc on day 1 ; figure 03B represented result of the treatment on day 3 after removal of Moxifloxacin disc and figure 03C and 03D represented result of the treatment with Moxifloxacin disc on day 7 after removal of Moxifloxacin disc.
Figure 03C and figure 03D show that bacterial infection was completely resolved on day 07 after removal of Moxifloxacin disc.

Example 3: Method for the treatment of a fungal posterior corneal infection with abscesses
1) Amphotericin B disc was prepared by the similar method as mentioned in example 1.
2) A deeper corneal plane was fashioned by Femtosecond laser with 1-2 incisions.
3) An Amphotericin B disc (50 µg/ml) was positioned in incised part for five days. Intra operative pictures of Amphotericin B disc implantation are shown in figure 05.
4) The implantable Amphotericin B disc was removed after five days and results were analyzed by AS-OCT and slit lamp Photography.

Studies were conducted on 4 patients with the fungal posterior corneal infection. Fungal corneal infection with abscess is shown in figure 04A, 04B, 04C 04D (Corneal OCT).
Figure 06A and 06B represented result of treatment of fungal posterior corneal infection with Amphotericin B disc on day 3 after removal of Amphotericin B disc and figure 06A and 06B represented fungal posterior corneal infections is resolving and it is not completely resolved.
Figure 07A, 07B and 07C represented result of the treatment of fungal posterior corneal infection with Amphotericin B disc on day 7 after removal of Amphotericin B disc. Figure 07A and figure 07B and 07C show that fungal corneal infection was completely resolved on day 07 after removal of Amphotericin B disc.

Example 4: Method for the treatment of a Nocardial infection
1) Amikacin disc was prepared by the similar method as mentioned in example 1.
2) A deeper corneal plane was fashioned manually with 1 incision.
3) An implantable Amikacin disc (0.4% w/v) was positioned in incised part for five days. Intra operative pictures of intracorneal Amikacin disc implantation are showed in figure 08A.
4) The implantable Amikacin disc was removed after five days and results were analysed by slit lamp Photography.

Studies were conducted on 1 patient with Nocardial corneal infection. The disc was removed on day 3, reimplanted and removed on day 7. Figure 08B represented result of the treatment of Nocardial infection with Amikacin disc on day 14 after removal of Amikacin disc. Figure 08B shows that Nocardial infection was completely resolved on day 14 after removal of Amikacin disc.

Example 5: Method for the treatment of a case who underwent therapeutic deep anterior lamellar keratoplasty (DALK)
1) A deeper corneal plane was fashioned by Femtosecond laser with 1-2 incisions.
2) Moxifloxacin disc (0.5% w/v) as prepared in example 1 was placed at the interface between donor and recipient corneal tissues and removed on day 5.
Moxifloxacin B disc placed in the interface during therapeutic deep anterior lamellar keratoplasty as shown in figure 09D
3) The implantable Moxifloxacin disc was removed after five days and results were analyzed by AS-OCT and slit lamp Photography.
Figure 09A represented pre-operative posterior corneal infection and figure 09B and figure 09C represented anterior lamellar keratectomy.

Studies were conducted on 2 patients that underwent therapeutic DALK. Figure 10B shows that infection was completely resolved within 14 days after plantation of the disc.

Example 6: Method for the treatment of infected keratoplasty case
1) A deeper corneal plane was fashioned manually with 1-2 incisions. Figure 11A represented segmental infection in a post keratoplasty.
2) Amikacin disc (0.4% w/v) was prepared in example 4 was placed in incised part. Intra operative pictures of intracorneal Amikacin disc implantation are shown in figure 11 B.
3) The implantable Amikacin disc was removed after five days and results were analyzed by AS-OCT and slit lamp Photography.

Studies were conducted on 1 patient with infected keratoplasty. Figure 11C represented clinical photos for the treatment of infected keratoplasty case after implantation of the Amikacin disc. Figure 11D shows that Infection was completely resolved within 14 days after implantation of the disc.

From the above foregoing examples, it is concluded that, novel implantable antimicrobial disc of the present invention is clinically effective and safe in the management of posterior corneal infections and abscesses. Further, we have not observed any surface toxicity in patients participated in the studies.
,CLAIMS:We Claim,
1. A novel implantable antimicrobial disc.
2. A novel implantable antimicrobial disc according to claim 1, comprising wafer and antimicrobial agent.
3. A novel implantable antimicrobial disc according to claim 1, wherein wafer is prepared by Whatman® 3 filter paper.
4. The antimicrobial disc according to claim 2, wherein antimicrobial agent is selected from group comprising antibacterial agent, antifungal agent, antiparasitic agent, antiviral agent or combination thereof.
5. The antimicrobial disc according to claim 1, wherein antimicrobial disc is sustained release antimicrobial disc.
6. The novel implantable antimicrobial disc according to claim 1, wherein antimicrobial disc is implanted at the infection site of corneal plane of the eye.
7. A process for the preparation of novel antimicrobial disc comprising of
a) preparing wafer of desired size and shape;
b) impregnating the wafer of step a) into antimicrobial agents for suitable time;
c) optionally maintaining the dose of the antimicrobial agent as required.
8. The process according to claim 7, wherein antimicrobial agent is prepared by dissolving antimicrobial agent and optionally pharmaceutically acceptable excipients in vehicle.
9. The process according to claim 8, wherein pharmaceutically acceptable excipients are selected from group comprising buffers, preservatives, antioxidants, chelating agents, surfactants, tonicity agents and polymers and vehicle is sterile water for injection.
10. A novel implantable antimicrobial disc for the treatment of corneal infection and abscesses wherein steps comprises
a) diagnosing the corneal infection with using diagnostic methods;
b) providing a stromal bed with 1-2 incision either manually or using femtosecond Lasers;
c) positioning of the implantable antimicrobial disc in incised place for 3 to 5 days;
d) removal of an implantable antimicrobial disc;
e) optionally re-implant the implantable antimicrobial disc if necessary.