668. In Vitro Evaluation of the Antifungal Activity of NVC-422 (N,N-dichloro-2,2-dimethyltaurine) Using a Novel Cadaver Nail Model
Session: Abstracts: Mycology
Friday, October 22, 2010
Background:

Onychomycosis is the most commonly diagnosed nail disorder.  Topical treatment of the infection is limited by the inability of currently available drugs to penetrate the human nail.  NVC-422 is a hydrophilic agent with potent antimicrobial activity making it a potential candidate as an effective ungal antifungal.  In this study, a novel in vitro infected human nail model was developed and used to evaluate the ability of novel NVC-422 gel formulations and nanoemulsion lacquers to penetrate and kill fungi grown on the subungal side. 

Methods:

T. mentagrophytes and T. rubrum were used to inoculate the ventral surface of the cadaver nails and incubated for one week at 30°C.  To ensure adequate infection of the nail, scrapings were stained with calcofluor white and examined microscopically for the presence of hyphae.  Infected nails were then treated with a single application of test NVC-422 formulations pipetted onto the dorsal surface of the nail, and incubated for another week.  Next, nails were cleaned with solvent to remove the applied formulations; ground and fungal viability determined as colony forming units (CFUs).  8% Ciclopirox lacquer was used as a comparator.

Results:

Our data showed that NVC-422 was able to penetrate the nail and effectively eradicate T. mentagrophytes and T. rubrum. The antifungal activities of the test formulations were evaluated based on: a) number of CFUs, and b) visual fungal growth on nails.  The novel gel formulations and nanoemulsion lacquers demonstrated significant nail penetration and antifungal activity following nail penetration indicated by no visual growth and a significant reduction in the CFUs.

Conclusion:

In this study we developed and evaluated a novel infected human cadaver nail model and used it to assess the penetration and activity of selected formulations. Our data showed that NVC-422 gel and nanoemulsion lacquer formulations, were able to penetrate the nail and eradicate the two most common fungal species causing onychomycosis.  Further evaluation of NVC-422 is warranted.


Subject Category: M. Mycology including clinical and basic studies of fungal infections

Speakers:
Sarah A. Ibrahim, PhD , Pharmaceutical Development, NovaBay Pharmaceuticals Inc., Emeryville, CA
Dmitri Debabov, PhD , Microbiology, NovaBay Pharmaceuticals Inc., 5980 Horton St. Suite 550, Emeryville, CA
Mahmoud Ghannoum, PhD , University Hospital Cleveland, Case West RU, Cleveland, OH
Mark Anderson, PhD , NovaBay Pharmaceuticals Inc.,, Emeryville, CA
Bahram Memarzadeh, PhD , NovaBay Pharmaceuticals Inc., Emeryville, CA

Disclosures:

S. A. Ibrahim, Yes
Novabay Pharmaceuticals: Employee, Salary

D. Debabov, Yes
NovaBay Pharmaceuticals: Employee,

M. Ghannoum, Yes
Pfizer: Consultant, Grant Investigator, Received grant, consulted and on their Speaker's Bureau and Speaker's Bureau,
NovaBay: Acted as a consultant and received grants, Consultant and Grant Investigator,
Novartis: Consulant and grant investigator, Consultant and Grant Investigator,
Astellas: Grant Investigator, Grant investigator and speaker's bureau and Speaker's Bureau,

M. Anderson, Yes
NovaBay Pharmaceuticals: Employee,

B. Memarzadeh, Yes
NovaBay Pharma: Employee,

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