Shampoos and other prepara- tions for scalp and hair condi-
13.9 Shampoos and other prepara- tions for scalp and hair condi-
Skin tions
13.1.1 Vehicles
13.10 Anti-infective skin prepara- tions
647 Both vehicle and active ingredients are important in the
13.10.1 Antibacterial preparations
treatment of skin conditions; the vehicle alone may have
13.10.1.1 more than a mere placebo effect. The vehicle affects the
Antibacterial preparations only degree of hydration of the skin, has a mild anti-inflamm- used topically
atory effect, and aids the penetration of active drug.
13.10.1.2 Antibacterial preparations also Applications are usually viscous solutions, emulsions, used systemically
or suspensions for application to the skin (including the
13.10.2 Antifungal preparations
scalp) or nails.
13.10.3 Antiviral preparations
Collodions are painted on the skin and allowed to dry to leave a flexible film over the site of application.
13.10.4 Parasiticidal preparations
Creams are emulsions of oil and water and are generally
13.10.5 Preparations for minor cuts and well absorbed into the skin. They may contain an anti- abrasions
microbial preservative unless the active ingredient or
13.11 basis is intrinsically bactericidal and fungicidal. Gener- Skin cleansers and antiseptics 656
ally, creams are cosmetically more acceptable than
13.11.1 Alcohols and saline
ointments because they are less greasy and easier to apply.
13.1.2 Suitable quantities for prescribing BNF 57 Gels consist of active ingredients in suitable hydrophilic
not apply to corticosteroid preparations—for suitable or hydrophobic bases; they generally have a high water
quantities of corticosteroid preparations see section content. Gels are particularly suitable for application to
the face and scalp. Lotions have a cooling effect and may be preferred to
ointments or creams for application over a hairy area. Lotions in alcoholic basis can sting if used on broken
13.1.3 Excipients and
skin. Shake lotions (such as calamine lotion) contain
sensitisation
insoluble powders which leave a deposit on the skin surface.
Excipients in topical products rarely cause problems. If a Ointments are greasy preparations which are normally
patch test indicates allergy to an excipient, products anhydrous and insoluble in water, and are more occlu-
containing the substance should be avoided (see also sive than creams. They are particularly suitable for
Anaphylaxis, p. 173). The following excipients in topical chronic, dry lesions. The most commonly used ointment
preparations are rarely associated with sensitisation; the bases consist of soft paraffin or a combination of soft,
presence of these excipients is indicated in the entries liquid and hard paraffin. Some ointment bases have both
for topical products. See also Excipients under General hydrophilic and lipophilic properties; they may have
Guidance, p. 2.
occlusive properties on the skin surface, encourage hydration, and also be miscible with water; they often have a mild anti-inflammatory effect. Water-soluble oint-
Imidurea ments contain macrogols which are freely soluble in
Beeswax
Isopropyl palmitate water and are therefore readily washed off; they have
Benzyl alcohol
Butylated hydroxyanisole N-(3-Chloroallyl)hexami-
a limited but useful role where ready removal is desir- Butylated hydroxytoluene nium chloride (quater- able.
Cetostearyl alcohol (includ- nium 15) ing cetyl and stearyl
Polysorbates Pastes are stiff preparations containing a high propor-
Propylene glycol tion of finely powdered solids such as zinc oxide and
alcohol)
Sodium metabisulphite starch suspended in an ointment. They are used for
Chlorocresol
Edetic acid (EDTA) Sorbic acid circumscribed lesions such as those which occur in
Wool fat and related sub- lichen simplex, chronic eczema, or psoriasis. They are
Ethylenediamine
stances including less occlusive than ointments and can be used to protect
Fragrances
Hydroxybenzoates (para-
lanolin 1
inflamed, lichenified, or excoriated skin.
bens)
Dusting powders are used only rarely. They reduce friction between opposing skin surfaces. Dusting pow- ders should not be applied to moist areas because they can cake and abrade the skin. Talc is a lubricant but it does not absorb moisture; it can cause respiratory irritation. Starch is less lubricant but absorbs water.