|Jmol-3D images||Image 1
|Molar mass||158.12 g mol−1|
|Appearance||colourless crystalline powder|
|Melting point||230 °C (446 °F; 503 K) (decomposes)|
|Boiling point||478 °C (892 °F; 751 K)|
|Solubility in water||0.57 g/100 mL (25 °C)
4.0 g/100 mL (75 °C)
|Solubility||soluble in alcohol, pyridine, NaOH
insoluble in ethyl ether
|LD50||> 5000 mg/kg (oral, rat)|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Named after the allantois (an amniote embryonic excretory organ in which it concentrates during development in most mammals except humans and higher apes[vague]), it is a product of oxidation of uric acid by purine catabolism. After birth, it is the predominant means by which nitrogenous waste is excreted in the urine of these animals. In humans and higher apes, the metabolic pathway for conversion of uric acid to allantoin is not present, so the former is excreted. Recombinant rasburicase is sometimes used as a drug to catalyze this metabolic conversion in patients. In fish, allantoin is broken down further (into ammonia) before excretion. Allantoin is a major metabolic intermediate in many other organisms including plants and bacteria.
Allantoin is present in botanical extracts of the comfrey plant and in the urine of most mammals. Chemically synthesized bulk allantoin, which is chemically equivalent to natural allantoin, is safe, non-toxic, compatible with cosmetic raw materials and meets CTFA and JSCI requirements. Over 10,000 patents reference allantoin. Manufacturers cite several beneficial effects for allantoin as an active ingredient in over-the-counter cosmetics, including: a moisturizing and keratolytic effect, increasing the water content of the extracellular matrix and enhancing the desquamation of upper layers of dead skin cells, increasing the smoothness of the skin; promoting cell proliferation and wound healing; and a soothing, anti-irritant, and skin protectant effect by forming complexes with irritant and sensitizing agents. A study published in 2009 reported the treatment of pruritus in mild-to-moderate atopic dermatitis with a topical non-steroidal agent containing allantoin.
It is frequently present in toothpaste, mouthwash, and other oral hygiene products, in shampoos, lipsticks, anti-acne products, sun care products, and clarifying lotions, various cosmetic lotions and creams, and other cosmetic and pharmaceutical products.
Since uric acid is the end product of the purine metabolism in humans, only non-enzymatic processes with reactive oxygen species will give rise to allantoin, which is thus a suitable biomarker to measure oxidative stress in chronic illnesses and senescence.
- Imidazolidinyl urea and diazolidinyl urea, antimicrobial condensation products of allantoin with formaldehyde.
- Young E. G., Wentworth H. P., Hawkins W. W. (1944). "The absorption and excretion of allantoin in mammals". J. Pharmacol. Experi. Therapeutics 81 (1): 1–9.
- Fujiwara, S; Noguchi T (1995). "Degradation of purines: only ureidoglycollate lyase out of four allantoin-degrading enzymes is present in mammals". The Biochemical Journal 312 (Pt 1): 315–8. PMC 1136261. PMID 7492331.
- Patent Lens search
- Veraldi, S; De Micheli, P; Schianchi, R; Lunardon, L (2009). "Treatment of pruritus in mild-to-moderate atopic dermatitis with a topical non-steroidal agent". Journal of drugs in dermatology : JDD 8 (6): 537–9. PMID 19537379.
- Thornfeldt, C (2005). "Cosmeceuticals containing herbs: fact, fiction, and future". Dermatologic Surgery 31 (7 Pt 2): 873–80. doi:10.1111/j.1524-4725.2005.31734. PMID 16029681.
- Kand'ár R, Záková P. (2008). "Allantoin as a marker of oxidative stress in human erythrocytes". Clinical chemistry and laboratory medicine : CCLM / FESCC 46 (9): 1270–4. doi:10.1515/CCLM.2008.244. PMID 18636793.
- Zitnanová I, Korytár P, Aruoma OI, Sustrová M, Garaiová I, Muchová J, Kalnovicová T, Pueschel S, Duracková Z (2004). "Uric acid and allantoin levels in Down syndrome: Antioxidant and oxidative stress mechanisms?". Clinica chimica acta; international journal of clinical chemistry 341 (1–2): 139–46. doi:10.1016/j.cccn.2003.11.020. PMID 14967170.