PCMX Antimicrobial Category I Status Supported By Test Results - Reckitt
This article was originally published in The Rose Sheet
Executive Summary
Topical antiseptic ingredient chloroxylenol, also called PCMX, possesses an antimicrobial effect on its own, unaffected by other formulation agents, Reckitt & Colman maintains in a Sept. 1 letter to FDA.
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Topical antiseptic ingredient chloroxylenol, also called PCMX, possesses an antimicrobial effect on its own, unaffected by other formulation agents, Reckitt & Colman maintains in a Sept. 1 letter to FDA. Reckitt, which markets PCMX-containing Dettol Liquid, asks the agency to classify chloroxylenol as a Category I (safe and effective) ingredient within the OTC antiseptics monograph. The tentative final monograph for topical antimicrobials lists PCMX as a Category III (data are insufficient) ingredient. At the time the TFM was published in June 1994, FDA determined existing data did not support the safety and effectiveness of PCMX (.24%-3.75%) for long-term use as an antiseptic handwash. The agency pointed to the need for both in vitro and in vivo tests. FDA also noted the "substantial germicidal activity" provided by other ingredients in PCMX products, such as isopropanol or pine oil, bring into doubt chloroxynol's contribution to the efficacy of the product. In support of its request, Reckitt submitted data from an EN 1040 test, which determines a product's bactericidal activity, comparing a "complete formulation" of Dettol with a PCMX-only version and a combination of pine oil and PCMX. Pine oil is listed as an active ingredient in Dettol, but Reckitt believes it "desirable to remove this active agent listing." Samples of the product and organism were combined for a five-minute contact period. After halting activity with a neutralizer, surviving bacteria were counted and the microbicidal effect calculated. "Dettol formulations lacking PCMX and both PCMX and pine oil displayed no detectable antimicrobial activity," while the complete formulation "displayed high efficacy," the company says. "This demonstrates that pine oil does not significantly contribute to the antimicrobial properties of Dettol liquid." Reckitt & Colman plans to wait for feedback from FDA before deciding whether to proceed with further tests. Other companies that have been campaigning the agency to reclassify PCMX include NIPA Hardwicke. OTC antiseptic product testing methodologies is one of several topics likely to be addressed in an upcoming "briefing document" being developed by the Cosmetic, Toiletry and Fragrance Association and Soap & Detergent Association (1 ). |