**3.4 Thymosin beta 4: a potential novel adjunct treatment for bacterial keratitis**

Topical Thymosin beta 4 (Tβ4) was an amino acid protein and it exerts a pharmacological action of promoting wound healing and reducing corneal inflammation when it is used as an adjunct to ciprofloxacin. The mechanism of action was reducing inflammatory mediators and inflammatory cell infiltration that gives an antibacterial activity and wound healing in the experimental model of *P. aeruginosa*-induced keratitis. Tβ4 as a novel therapeutic method has the potential to treat corneal pathogenesis and other infections including immune-based inflammatory diseases [19].

## **3.5 Novel drug repository contact lens**

Ponniah et al. [20] studied a newer drug-delivery mechanism, called the drugdepository contact lens (DDCL; Hyper-CL (Acofilcon A)), and evaluated the effectiveness of DDCLs for bacterial keratitis.

It was an open-label randomized controlled trial that compares the topical antimicrobial eye drops with and without the application of DDCL in treating bacterial keratitis.

The basic principle was fenestration; that is, the topically administered antibiotic drop would migrate through the fenestration holes and reaches the space between the backside of the therapeutic contact lens and the corneal surface. This increased the contact time of antibiotic eye drop and wound, thus enabling relatively speedy recovery when compared to conventional antibiotic eye drop alone.

They evaluated the effects of DDCL using clinical parameter guidelines recommended by the American Academy of Ophthalmology, *viz*., corneal infiltration size, ulcer size, anterior chamber reactions, corneal haze, visual acuity, and pain. Topical antibiotic Moxifloxacin (0.5%), a Fourth-generation fluoroquinolone having a wide spectrum of antibacterial activity, was used in the study.

In this study, it was observed that corneal infiltration resolution was on day 5 in the antibiotic-only group and day 3 in the DDCL group. Both the groups had lesions healed completely after 2 weeks; however, improvement in terms of healing and pain score was significant in the DDCL group (**Figures 1** and **2**) [20].

DDCL, a therapeutic soft contact lens that was also a repository contact lens, has facilitated the promotion of healing and pain relief in patients suffering from BK. The extended contact of antibiotics over the corneal surface has impacted faster healing of ulcers without an experience of ocular surface toxicity.

*Alternative Treatment Approaches in Bacterial Keratitis DOI: http://dx.doi.org/10.5772/intechopen.112624*

#### **Figure 1.**

*Corneal ulcer heal in BK infection—DDCL + antibiotics along with corneal OCT.*

**Figure 2.** *Changes in pain over time.*

#### **3.6 Novel implantable sustained release antibacterial disc**

Intra corneal sustained-release dosage forms are novel targeted drug delivery systems to release a drug slowly to maintain a constant drug concentration at the site of action for a specific time with minimum side effects such as ocular surface toxicities.

A novel implantable sustained-release antibacterial disc that provides a likely effect in the treatment of posterior corneal infections and abscesses regarding effective drug penetration and reduced surface toxicities was investigated by the team in South India (**Figure 3**).

**Figure 3.** *Implantable sustained release antibacterial disc [21].*
