Chemical Properties
Imidazolidinyl urea is a stable white, free-flowing odorless powder with a mild odour. It does not absorb ultraviolet light, and decomposes at temperatures above 160°C (Sheppard and Wilson, 1974). In aqueous solution the pH is close to neutrality. It is mainly contained in cosmetics and liquid soaps.
Uses
imidazolidinyl urea is one of the most commonly used anti-bacterial preservatives given its low sensitizing potential. In 2010, it was the tenth most frequently used preservative in the united States (parabens ranged from first to sixth place). generally, imidazolidinyl urea is not used alone but as a copreservative with parabens for broad-spectrum activity. Although it may yield low levels of formaldehyde when subjected to destructive methods-such as exposure to high temperatures-under normal use conditions, there is no detection of free formaldehyde release. of all the formaldehydereleasing preservatives, imidazolidinyl urea is the one least likely to cause skin sensitization and allergic reactions.
Production Methods
Imidurea is produced by the condensation of allantoin with
formaldehyde.
Definition
ChEBI: Imidazolidinyl urea is a member of ureas. It has a role as an antimicrobial agent. It is an antimicrobial preservative used in cosmetics. It acts as a formaldehyde releaser.
General Description
Imidazolidinyl Urea is a non-aromatic, polar, hydrophilic antimicrobial compound. It is used as a preservative in a variety of applications, most notably in personal care products and cosmetics. It is effective against a broad spectrum of bacteria, fungi and yeast. It is used as a preservative in cosmetics, shampoos, deodorants, body lotions, and in some therapeutic topical ointments and creams.
Flammability and Explosibility
Non flammable
Pharmaceutical Applications
N,N-methylenebis N'-1-(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl urea is a broad-spectrum antimicrobial preservative used in cosmetics and topical pharmaceutical formulations; typical concentrations used are 0.03–0.5% w/w. It is effective between pH 3–9 and is reported to have synergistic effects when used with parabens.
Contact allergens
Imidazolidinyl urea, a formaldehyde releaser related to
diazolidinyl urea (see above), is used as an antimicrobial
agent very active against Gram-positive and Gram-negative
bacteria, used as a synergist in combination with para-
bens. It is used as a preservative in aqueous products,
mainly in cosmetics, toiletries, and liquid soaps.
Safety
Imidurea is widely used in cosmetics and topical pharmaceutical
formulations, and is generally regarded as a nontoxic and
nonirritant material. However, there have been some reports of
contact dermatitis associated with imidurea, although these are
relatively few considering its widespread use in cosmetics.
Although imidurea releases formaldehyde, it does not appear to
be associated with cross-sensitization with formaldehyde or other
formaldehyde-releasing compounds.
LD50 (mouse, oral): 7.2 g/kg
LD50 (rabbit, skin): > 8 g/kg
LD50 (rat, oral): 11.3 g/kg
storage
Imidurea is hygroscopic and should be stored in a well-closed
container in a cool, dry place.
Incompatibilities
N,N-methylenebis N'-1-(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl urea is incompatible with strong oxidants. It is compatible with other preservatives including sorbic acid and quaternary ammonium compounds. It is also compatible with other pharmaceutical and cosmetic excipients including proteins, nonionic surfactants, and lecithin.
Regulatory Status
Included in the FDA Inactive Ingredients Database (topical
preparations). Accepted for use in cosmetics in Europe and the
USA. Included in the Canadian List of Acceptable Non-medicinal
Ingredients.
