Formulation and evaluation of an effective pH balanced topical antimicrobial product containing tea tree oil

Pharmazie. 2005 Mar;60(3):208-11.


The effect of pH on the antimicrobial activity of Melaleuca alternifolia essential oil formulations was studied. Microemulsions, liposomal dispersions, multiple emulsions and a colloidal bed of sterile clay were formulated using 5% w/w of tea tree oil. A number of formulations were prepared at various pH values (5.0, 5.5, 6.0, 6.5, and 7.0). Thermal stability studies showed that the formulations were stable for more than eight months. Agar dilution tests showed MICs of 1.0% v/v S. aureus and S. epidermidis. In the broth dilution test, MBC of the oil for P. acnes was 0.5% v/v. MIC and MBC values were comparable to those of non-formulated tea tree oil, indicating that tea tree oil retained its activity in the above-mentioned formulations. The microbiological evaluation showed that the formulations containing 5% w/w tea tree oil had a maximum effect at pH 5.5.

MeSH terms

  • Acne Vulgaris / drug therapy
  • Acne Vulgaris / microbiology
  • Anti-Infective Agents / chemistry*
  • Anti-Infective Agents / pharmacology*
  • Chemistry, Pharmaceutical
  • Colloids
  • Drug Stability
  • Emulsions
  • Hot Temperature
  • Hydrogen-Ion Concentration
  • Liposomes
  • Microbial Sensitivity Tests
  • Propionibacterium acnes / drug effects
  • Staphylococcus aureus / drug effects
  • Staphylococcus epidermidis / drug effects
  • Tea Tree Oil / chemistry*
  • Tea Tree Oil / pharmacology*


  • Anti-Infective Agents
  • Colloids
  • Emulsions
  • Liposomes
  • Tea Tree Oil