Topical Sustained Delivery of Miltefosine Via Drug-Eluting Contact Lenses to Treat Acanthamoeba Keratitis

Mel4-coated hyaluronic acid-laden etafilcon A contact lenses: Improved wettability with retained antimicrobial properties

Soft contact lenses are a common mode of vision correction used worldwide. However, contact lens wearers often experience discomfort and are at risk of developing microbial infections. To address these issues, we designed Mel4-coated hyaluronic acid-laden etafilcon contact lenses to improve wettability while providing antimicrobial properties. The process involved the interaction of the etafilcon lens, which carries a net negative charge, with positively charged Mel4 (a cationic antimicrobial peptide). This was followed by interaction with hyaluronic acid (a negatively charged polymer). The components were then crosslinked using EDC-NHS [N-(3-dimethyl aminopropyl)-N'-ethyl carbodiimide hydrochloride and N-Hydroxy succinimide] to form amide bonds between the compounds and the lens. In this study, four batches of lenses were prepared: the first consisted of conventional HA-soaked lenses (SM-HA-L), the second consisted of lenses soaked in Mel4 and HA (SM-Mel4-HA-L), the third batch consisted of HA crosslinked with the lens (HA-Cr-L), and the fourth consisted of lenses soaked in Mel4 and HA, followed by crosslinking (Mel4-HA-Cr-L). During the washing and sterilization steps, SM-HA-L lenses showed high leaching compared to SM-Mel4-HA-L lenses, while HA-Cr-L and Mel4-HA-Cr-L lenses showed no leaching. A hyaluronidase breakdown assay revealed 5.37 μg, 9.28 μg, 8.04 μg, and 6.07 μg of HA per lens for SM-HA-L, SM-Mel4-HA-L, HA-Cr-L, and Mel4-HA-Cr-L, respectively. The wettability (contact angle) of SM-Mel4-HA-L lenses was improved compared to HA-Cr-L and Mel4-HA-Cr-L lenses. In vitro release studies showed no leaching of HA, indicating permanent entrapment or binding of HA to the contact lens surface. Both the SM-Mel4-HA-L lenses and crosslinked Mel4-HA-Cr-L lenses could significantly reduce the adhesion of Pseudomonas aeruginosa 6294 and Staphylococcus aureus 31 to the lenses. In conclusion, the presence of HA improved wettability, while Mel4 retained its antimicrobial activity, highlighting its potential to advance existing contact lens technology with improved wettability and antimicrobial properties.

New Frontiers in Acanthamoeba Keratitis Diagnosis and Management

Acanthamoeba Keratitis (AK) is a severe corneal infection caused by the Acanthamoeba species of protozoa, potentially leading to permanent vision loss. AK requires prompt diagnosis and treatment to mitigate vision impairment. Diagnosing AK is challenging due to overlapping symptoms with other corneal infections, and treatment is made complicated by the organism's dual forms and increasing virulence, and delayed diagnosis. In this review, new approaches in AK diagnostics and treatment within the last 5 years are discussed. The English-language literature on PubMed was reviewed using the search terms "Acanthamoeba keratitis" and "diagnosis" or "treatment" and focused on studies published between 2018 and 2023. Two hundred sixty-five publications were initially identified, of which eighty-seven met inclusion and exclusion criteria. This review highlights the findings of these studies. Notably, advances in PCR-based diagnostics may be clinically implemented in the near future, while antibody-based and machine-learning approaches hold promise for the future. Single-drug topical therapy (0.08% PHMB) may improve drug access and efficacy, while oral medication (i.e., miltefosine) may offer a treatment option for patients with recalcitrant disease.