The name ‘lanolin’ covers wool fat, wool wax and wool alcohol as well as their various constituents. Lanolin is an emulsifier present in many topical medicaments, such as ointments and creams, and in many cosmetics. ‘Parabens’ is the collective name for the alkyl (methyl, ethyl, propyl and butyl) esters of p-hydroxybenzoic acid used as preservatives in cosmetics and other topical applications, especially creams and lotions: they are amongst the most satisfactory preservatives. Lanolin and parabens are the constituents of the vehicles used for local applications which most frequently cause contact hypersensitivity.1 For example, it has been estimated that about 1–2% of patients with eczema or dermatitis are allergic to lanolin, though such allergy is very rare in people with a normal skin. The possibility of contact allergy should be considered in any case of persistent or recurrent eczematous dermatitis which responds poorly to treatment, and the patient should be patch-tested.
Molecular association of normal alkanoic acids with their thallium(I) salts: a new homologous series of fatty acid metal soaps