Evaluation of preservative effectiveness of liquid crystalline systems with retynil palmitate by the challenge test and D-value
Chorilli, M.; Leonardi, G.R.; Salgado, H.ér.R.N.; Scarpa, M.V.ín.
Journal - Association of Official Analytical Chemists 94(1): 118-127
2011
ISSN/ISBN: 0004-5756 PMID: 21391488 Document Number: 652669
The objective of this work was to evaluate the preservative effectiveness of liquid crystalline systems containing retynil palmitate (RP) by the challenge test (CT) and D-value. A system was developed containing water, silicon glycol copolymer, and polyether functional siloxane with 1% RP added. The analyses were carried out by methods in the U.S. Pharmacopeia (USP 31, 2008) using the microorganisms Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger. The CT showed that after 7 days, all microorganisms were eliminated except A. niger, which maintained viability for at least 28 days after inoculation. Moreover, the microorganisms E. coli, P. aeruginosa, S. aureus, C. albicans, and A. niger presented different growth behaviors, evidenced by differences among the D-values calculated. It was concluded that the CT and D-value were efficient methods for evaluation of the preservative property of these formulations.