Screening of Nanoemulsion Formulations and Identification of NB-201 as an Effective Topical Antimicrobial for Staphylococcus aureus in a Mouse Model of Infected Wounds.

Despite advances in antimicrobial therapies, wound infection remains a global public health concern. We aimed to formulate and assess various nanoemulsions (NEs) for potential effectiveness as stable antimicrobial agents suitable for topic application. A total of 106 NEs were developed that varied with respect to nonionic and cationic surfactants. Stability testing demonstrated that the NEs tested are broadly stable, with 97/106 formulations passing 2-week stability tests. Two NEs, NB-201 and NB-402, were selected to test antimicrobial activity in a wound model in mice. Skin abrasion wounds were infected with Staphylococcus aureus followed by NE treatment. Infected skin was then evaluated by measuring colony forming units. NB-201 reduced median bacterial counts by 4 to 5 log compared to animals treated with saline, whereas NB-402 reduced bacterial counts by 2 to 3 log. Additional stability tests on NB-201 demonstrated that NB-201 is stable in the presence of human serum, and is stable for at least 6 months at 5°C, 25°C, and 40°C. Finally, in in vitro studies, NB-201 was found to be effective against S. aureus at a higher dilution than the commercially available silver sulfadiazine. Altogether these results demonstrate that NB-201 is a stable and effective topical antimicrobial for the treatment of S. aureus.

Nanoemulsion Therapy for Burn Wounds Is Effective as a Topical Antimicrobial Against Gram-Negative and Gram-Positive Bacteria.

The aim of this study is to investigate the antimicrobial efficacy of two different nanoemulsion (NE) formulations against Gram-positive and Gram-negative bacteria in an in vivo rodent scald burn model. Male Sprague-Dawley rats were anesthetized and received a partial-thickness scald burn. Eight hours after burn injury, the wound was inoculated with 1 × 10(8) colony-forming units of Pseudomonas aeruginosa or Staphylococcus aureus. Treatment groups consisted of two different NE formulations (NB-201 and NB-402), NE vehicle, or saline. Topical application of the treatment was performed at 16 and 24 hours after burn injury. Animals were killed 32 hours after burn injury, and skin samples were obtained for quantitative wound culture and determination of dermal inflammation markers. In a separate set of experiments, burn wound progression was measured histologically after 72 hours of treatment. Both NE formulations (NB-201 and NB-402) significantly reduced burn wound infections with either P. aeruginosa or S. aureus and decreased median bacterial counts at least three logs when compared with animals with saline applications (p < .0001). NB-201 and NB-402 also decreased dermal neutrophil recruitment and sequestration into the wound as measured by myeloperoxidase (MPO) assay and histopathology (p < .05). In addition, there was a decrease in the proinflammatory dermal cytokines (interleukin 1-beta [IL-1ß], IL-6, and tumor necrosis factor alpha [TNF-α]) and the neutrophil chemoattractants CXCL1 and CXCL2. Using histologic examination, it was found that both NB-201 and NB-402 appeared to suppress burn wound progression 72 hours after injury. Topically applied NB-201 and NB-402 are effective in decreasing Gram-positive and Gram-negative bacteria growth in burn wounds, reducing inflammation, and abrogating burn wound progression.

Discovery of a series of 2-(1H-pyrazol-1-yl)pyridines as ALK5 inhibitors with potential utility in the prevention of dermal scarring.

A series of 2-(1H-pyrazol-1-yl)pyridines are described as inhibitors of ALK5 (TGFß receptor I kinase). Modeling compounds in the ALK5 kinase domain enabled some optimization of potency via substitutions on the pyrazole core. One of these compounds PF-03671148 gave a dose dependent reduction in TGFß induced fibrotic gene expression in human fibroblasts. A similar reduction in fibrotic gene expression was observed when PF-03671148 was applied topically in a rat wound repair model. Thus these compounds have potential utility for the prevention of dermal scarring.