The efficiency, tolerability, and applicability of topical agents are directly related to employed vehicles. Thus to achieve optimum topical therapy, a solid knowledge of the vehicles, their composition, and their physical and dermato-pharmacological actions are important. Common vehicles are complex mixtures consisting of diverse ingredients belonging to six major groups, i. e. hydrophilic and lipophilic bases, emulsifiers, gel-forming agents, preservatives, and antioxidants. This makes it possible to optimize both the cosmetic features and to adjust a vehicle to the properties of an incorporated drug and site of application. On the other hand it makes it difficult to make a proper choice between several alternatives or to use it in individual prescriptions. In order to simplify the selection of a formulation, it is useful to categorize them systemically into several groups, such as ointments, creams, gels, emulsions, and suspensions. Within these groups some general rules can be derived for the selection of a vehicle with respect to skin conditions and the application site. When active substances are incorporated into a base the dermato-biopharmaceutical properties of the whole system (drug + vehicle) also have to be considered. If for a given vehicle drug transport into the skin does not suffice, several methods are described to facilitate its penetration, such as by hydrating the skin or by adding chemical penetration enhancers.

The 10% glycolic acid containing oil-in-water emulsion improved mild acne applied as monotherapy in this study significantly, already after 45 days of treatment. Regarding tolerability, there was no objective or subjective difference between the 10% glycolic acid containing oil-in-water emulsion and the corresponding placebo.

Although considerable amounts of testosterone remain on the intact skin for several hours after evaporation of the alcohol vehicle, contamination of a second, especially female or prepubertal, subject causing side-effects seems very unlikely.

The visibility of a skin condition or dermatosis led to the reasonable assumption that the direct application of a therapeutic remedy to the target tissue holds many advantages. Through centuries, the nomenclature of topical preparations has proliferated and finally been moulded into the compulsory nomenclature of official compendia. In everyday life, many terms have been added and have complicated understanding and communication among and between healthcare professionals and laypersons. A large proportion of marketed topical preparations contain significant amounts of volatile vehicle ingredients that evaporate once they are applied onto the skin, that is, the vehicle format as well as the sum of vehicle ingredients in the primary container are different from the vehicle format and the sum of vehicle ingredients on the skin. This phenomenon and the potential consequences have so far been often ignored by many healthcare professionals and laypersons. To gain a better understanding, this phenomenon has been coined as the metamorphosis of the vehicle. The metamorphosis of the vehicle describes the vehicle (a) in the primary container (primary formulation), (b) during and immediately after application onto the skin (secondary formulation) and (c) after all volatile vehicle ingredients have evaporated from the vehicle on top of the skin (tertiary or residual formulation). The secondary and tertiary formulations may offer increased delivery of cosmetic or pharmaceutical actives. This is achieved by (a) an intended post-application creation of supersaturation of actives in the secondary and tertiary formulations or by (b) physico-chemical triggers such as pH.

The investigated Ec. extract shows great potential in alleviating cutaneous symptoms of AE, and by exerting remarkable anti-inflammatory actions and restoring the epidermal lipid barrier, it will be very likely a well-tolerated, powerful novel ingredient for the adjuvant therapy of AE.