PHMB: Mode of Action

Topical antimicrobials are beneficial in the management of wound bioburden and wound healing. With the requirement for frequent use, and resistance concerns to antibiotics there are limited options available.
The antimicrobial agent PHMB (polyhexamethylene biguanide), is known for its use in medical applications such as Contact Lens solutions. More recently PHMB has been demonstrated to be effective in wound care. This study looks to collate known information and antimicrobial testing to assess the uses and benefits of PHMB.

Testing:
 
 
PHMB impregnated foam dressing demonstrated total eradication of all the challenge organisms tested within 24hrs. Some bacteria tested were eradicated within as little as 6hrs.
 
Literature review:
PHMB has two proposed modes of action:
1) Attachment to the surface molecules of microbes and disruption of its membrane causing a loss of cell function and, ultimately, destruction of the microbe.1
2) An alternative mode of action where PHMB enters the bacterial cell and can directly interact with chromosomal DNA, which is not protected by a nucleus, causing cell death. This protects mammalian cells as PHMB becomes entrapped unable to enter the nuclei, and therefore doesn’t display toxic effect.2, 5
Studies have shown that PHMB improves wound healing by promoting contraction wound closure significantly more than the placebo and octenidine3. It has also been shown that PHMB treated wounds heal faster than those cleansed with saline.4

In-vitro testing has demonstrated that PHMB is efficacious in the management of bioburden. A review on the mode of action has highlighted the benefits of PHMB in wound healing, and has highlighted no evidence of bacterial resistance. Studies suggest PHMB is a credible alternative to traditional topical antimicrobials

Trademarked Items (if applicable):

References (if applicable): 1) Kaehn K. Skin Pharmacol Physiol 2010; 23 (suppl 1): 7-16
2) Sowlati-Hashjin A. J.Phys Biochem 2020; 124,22-4487
3) Kramer et al. Skin Pharamcol Physiol 2004; 17:141-146
4) Andriessen and Eberlein. Wounds 2008 20:71-75
5) Chindera, K. et al. (2016). The antimicrobial polymer PHMB enters cells and selectively condenses bacterial chromosomes. Scientific Reports, 6(1).