Both Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) have the lowest minimum inhibitory concentrations among the bacterial groups. The MIC 90 s to Brilacidin for Streptococcus pneumonia (SP), Streptococcus viridians (SV), Moraxella (MS), Haemophilus influenza (HI), Pseudomonas aeruginosa (PA), and Serratia marcescens (SM) are 4, 32, 256, 32, 16, and 128-fold higher, respectively, than SA and SE. Brilacidin has Gram-positive in vitro activity; topical Brilacidin 0.5% is minimally irritating; and Brilacidin 0.5% was equally efficacious as Vancomycin (VAN) in a methicillin-resistant S. aureus (MRSA) keratitis model when the corneal epithelium is removed. Brilacidin acts primarily on the bacterial cell membrane by depolarization. Brilacidin is more potent for Gram-positive bacteria (except SV) than Gram-negative bacteria[2].

Brilacidin demonstrates dose-dependent ocular toxicity after 7 topical instillations (every 30?min for 3?h) in the NZW rabbit ocular toxicity model. Brilacidin 1% is determined to be Mildly Irritating (23.0), Brilacidin 0.5% (6.5), and Brilacidin 0.25% (4.0) are determined to be Minimally Irritating, while Brilacidin 0.1% (2.0) and TBS (1.0) are determined to be Practically Nonirritating and 0.01% Brilacidin (0.5) is determined to be Nonirritating based on their Maximum mean total scores (MMTS) values[2].