Date: 1st May 2001
THE AUSTRALIAN SOCIETY OF COSMETIC CHEMISTS
Prepared by Henry King, BSc
Because of physiologic characteristics in newborn babies (see Figure 1), products formulated for babies require special consideration. Figure 1 is included in this paper to give a better understanding of differences between these characteristics and those of an adult (Ref. W.B. Saunders).
Baby products are those toiletries that are used on infants from birth to toddler age, and normally cover the following product type: creams, lotions, oils, ointments, powder, shampoos, soaps/washes, sunscreens and wipes. Baby products therefore cover the full spectrum of toiletries and are quite frequently also used by adults.
Sunscreens are used more extensively on children as the population becomes more aware of the effects of UVA and UVB radiation from the sun. The Position Paper on Sunscreens prepared by Dr. Malcolm Nearn adequately covers this topic. However, it is recommended that sunscreens not be used on children under the age of six months.
TO BE CONSIDERED
Methemoglobin is defined as a brownish compound formed when haemoglobin is oxidised by oxygen (Ref. The Macquarie Dictionary page 1097).(2) Newborn infants are at increased risk of methemoglobinemia due to diminished enzyme systems required to reduce ferrihemoglobin to ferrohemoglobin. Fetal hemoglobin is more easily oxidized than adult hemoglobin. (3)
Less commonly, neonates can acquire methemoglobinemia from exposure to oxidants, such as aniline dyes used for nappy (diaper) markings, disinfectants, and products containing resorcinol, a local irritant with antifungal, antibacterial and mild keratolytic actions used in topical preparations.(3)
Reference: Tush and Kuhn, Ann Pharmacother 1996:30:1251-4.
Skin pH and Contactants
Skin defence against penetration from the outside is afforded in the main by the outermost stratum corneum or horny layer. The surface layers are endowed with protective capabilities and together with the other layers of the epidermis are separated from the dermis by the barrier of the basement membrane. The acid pH of the skin serves in the defence against microorganisms. The very mechanism by which surface pH is homeostatically controlled provides resistance against extraneous alkali and acid. The surface skin participates in the defence against excessive removal of water and water-soluble substances. (Many baby products are used to prevent, aid, soothe and minimise nappy (diaper) rash – or diaper dermatitis).
Diaper (nappy) dermatitis results from a number of factors, including dampness, ammonia, occlusion, maceration, abrasion, fecal enzymes and irritant chemicals. Secondary infection with Candida albicans or bacteria may occur (4) from prolonged wetness which leads to maceration, greater friction, increased skin permeability and microbial growth.
Bacteria probably contribute to increasing the pH level, which promotes fecal enzyme activity, in particular proteases and lipases that act as irritants.
Hence products should aid in keeping the skin as dry as possible and keep pH at a normal acidic level. Baby wipes that contain propylene glycol or alcohol are not recommended for irritated skin in the nappy (diaper) area (6).
The efficacy of topical preparations will be enhanced, at least theoretically, if they act also to preserve or restore a normal skin pH. Properly buffered ointments and creams are not only widely preferred in the prophylaxis of skin lesions such as nappy (diaper) dermatitis, but also as vehicles for specific products to be applied topically.
Radiating the final product can have disastrous effects on the package, on the colour of the contents and could cause deterioration of the product.
pH measurements will vary over the skin surface of the body. Figure 2 illustrates the sites of potentiometric skin pH measurements, and gives the obtained readings on a young boy. pH readings done on 12 low birth weight infants aged 2-8 days varied from 5.3 to 6.9. Be aware that surface pH may decrease with a rise in sweating rate, since eccrine sweat acidity is directly related to sweat flow.
Frequently used raw materials that cause some concern are as follows:
1. Liquid Paraffin - used as an ingredient of ointment bases, as an emollient and cleanser in certain skin conditions, and as an ophthalmic lubricant.
Adverse effects and precautions: Excessive dosage by mouth or rectum may result in anal seepage and irritation. Liquid paraffin is absorbed to a slight extent and may give rise to foreign body granulomatous reactions.(7)
2. Propylene Glycol – used as a humectant and co-solvent.
Adverse effects and precautions: Propylene glycol may cause some local irritation of the skin and mucous membrane. Hypersensitivity reactions have been reported but skin reactions due to propylene glycol are generally rare. There is evidence of topical absorption when applied to damaged skin. (7)
3. Purified Talc – used in massage and as a dusting powder to allay irritation and prevent chafing. Talc must be sterilised.
Adverse effects and precautions: Contamination of wounds or body cavities with talc is liable to cause granulomas. Inhalation of talc can cause respiratory irritation. Prolonged exposure to talc may produce pneumocomosis. Talc is liable to be heavily contaminated with bacteria including Clostridium tetani, CL welchii and Bacillus anthracis, hence it must be sterilised. The routine use of non-medicated powders in the skin care of infants can be hazardous. Talc acts as a pulmonary irritant and inhalation of baby powder by infants has caused severe respiratory difficulties.
There have been reports of umbilical granulomas resulting from contamination of umbilical stumps with talcum powder used for skin care. (7)
Reference: Martindale 31, 1096, 1745, 1407.
It is essential that all aqueous systems maintain the skins’ pH, use very mild ingredients and ensure all fragrances are hypo-allergenic; have no irritating solvents or carriers; and contain appropriate preservatives where justified. Powder ingredients must be sterilised by either ethylene oxide or gamma radiation.
Figure 1 Francine H. Nichols and Elaine Zwelling—Maternal Newborn Nursing Theory and Practice 1997, p48. W.B.Saunders Company
2..The Macquarie Dictionary 1982 p1097
3..Gretchen M. Tush and Robert J Kuhn Methemoglobinemia Induced By An Over The Counter Medication. Ann Pharmacother 1996 30:1251-4
4..Srisupalak Singalavanija and Ilona J. Frieden—Diaper Dermatitis-Pediatrics in Review Vol 16 No4 April 1995, p142
5.Ulrike I. Sires and Susan B. Mallory—Diaper Dermatitis How to treat and Prevent Vol 98 No6 Dec 1995 PostGraduate Medicine p79-81,84
Figure 2 Hans behrendt and Marvin Green Dept. of Pediatrics New York Medical College New York Thomas Books Chapters 3,9,10 p89
7. Mardindale 31 P1096,1745,1407
Click here for attachments