RT Journal Article SR Electronic T1 A Method for Evaluating the Effectiveness of Preservative Systems in Water-Immiscible Ointments JF PDA Journal of Pharmaceutical Science and Technology JO PDA J Pharm Sci Technol FD Parenteral Drug Association (PDA) SP 216 OP 221 VO 36 IS 5 A1 Robert L. Abshire A1 Barry A. Schlech YR 1982 UL http://journal.pda.org/content/36/5/216.abstract AB A procedure designed specifically for determining the effectiveness of antimicrobial preservatives in an ophthalmic ointment was evaluated. Except for Staphylococcus aureus, the United States Pharmacopeia XX battery of challenge microorganisms worked well in the system. The results indicate that this procedure can be used to challenge preserved ointments and determine if such preparations meet the same test requirements as those set forth in the compendium for preserved solutions and suspensions. It is proposed that other laboratories study this method so that its usefulness for evaluating the effectiveness of preservatives in ointments can be defined.