Iodopropynyl Butylcarbamate

Conclusion

In the 1998 safety assessment of iodopropynyl butylcarbamate (IPBC), the Cosmetic Ingredient Review Expert Panel (Panel) stated that IPBC is safe as a cosmetic ingredient at concentrations ≤0.1% and should not be used in products intended to be aerosolized. ¹ Since that assessment, the Panel reviewed additional studies along with updated frequency and concentration of use information (Table 1). ^{2 –21} At the September 2013 meeting, the Panel determined that this safety assessment should not be reopened.

Table 1.

Historic and Current Uses and Concentrations. ^1,5,6,a,b

	No. of uses		Maximum concentration of use (%)
	Iodopropynyl butylcarbamate
Data year	1996	2013	1995	2013
Totals	122	942	0.005-0.0125	0.00012-0.05
Duration of use
Leave-on	44	564	0.005-0.0125	0.001-0.05
Rinse-off	78	364	0.0125	0.00012-0.05
Diluted for (bath) use	NR	14	NR	0.015
Exposure type
Eye area	NR	45	NR	0.009-0.023
Incidental ingestion	NR	NR	NR	NR
Incidental inhalation—sprays	9	48	0.01-0.0125	0.001-0.02
Incidental inhalation—powders	NR	1	NR	0.02
Dermal contact	38	548	0.005-0.0125	0.002-0.05
Deodorant (underarm)	NR	NR	NR	0.0075-0.02
Hair—noncoloring	73	374	NR	0.00012-0.05
Hair coloring	10	14	NR	0.0078-0.011
Nail	1	1	NR	0.03
Mucous membrane	NR	102	NR	0.015-0.05
Baby products	NR	14	NR	NR

Abbreviation: NR, not reported.

^aBecause each ingredient may be used in cosmetics with multiple exposure types, the sum of all exposure type uses may not be equal to the sum of total uses.

^bTotals = Rinse-off + leave-on product uses.

Discussion

During the Panel discussion, the European Union’s (EU) 0.1% concentration limit on IPBC in cosmetics was noted. Currently, the following 3 maximum concentrations of this ingredient, which are authorized for use in cosmetics, are in effect in the EU, each of which is lower than the 0.1% limit previously determined: (1) rinse-off products (0.02%), (2) leave-on products (0.01%, except deodorants/antiperspirants), and (3) deodorants/antiperspirants (0.0075%). Furthermore, this ingredient is not to be used in oral hygiene and lip care products, and the following warning must be displayed on the label of rinse-off and leave-on cosmetic products that contain IPBC: not to be used for children aged younger than 3 years. Using the Scientific Committee on Cosmetic Products and Non-food Product’s opinion on IPBC as the basis for the EU’s limitations, the Panel noted that these limitations are based on concerns relating to potential iodine release from this ingredient and subsequent overdose. However, the Panel agreed that it is not likely that iodine release from IPBC would be significant enough at use concentrations to affect thyroid function or produce iodine overload, particularly after considering that effects on the thyroid gland were not reported in a 104-week, chronic oral toxicity study on this ingredient (up to 80 mg/kg/d) involving rats. ¹ The absence of evidence that IPBC causes thyroid toxicity in this study was also considered along with the absence of evidence that this ingredient can be dehalogenated to produce free iodine in animals or in humans. The Panel also noted that the available irritation and sensitization data do not suggest that IPBC is unsafe for use in cosmetic products at concentrations up to 0.05%, the highest maximum use concentration reported in a survey of ingredient use concentrations. ^{1,10 –20}