A method of selecting the constituent elements of a therapeutic composition for application to wounds having a pathogen load is disclosed. The method includes selecting a pharmaceutical active agent selected from a list of pharmaceutical active agents approved for over the counter non-prescription use, and said pharmaceutical active agent having suitable activity to kill the desired pathogens； identifying a tissue permeation enhancer from a list of generally recognized and safe tissue permeation enhancers that facilitates penetration of a composition using the selected tissue permeation enhancer through the stratum corneum of mammalian tissue； selecting a hygroscopic carrier agent suitable for mixing in solution with the tissue permeation enhancer and the pharmaceutical active agent； said hygroscopic carrier agent being selected from a list of generally recognized and safe hygroscopic carrier agents； and ensuring that the activity/water (AW) measurement of the composition is less than the AW measurement for a target pathogen in a tissue wound.
