Comedogenicity in Rabbit: Some Cosmetic Ingredients/Vehicles

Abstract

The rabbit external ear canal was used to define which chemicals caused comedone formation on topical application. Some of the tested ingredients are currently used in topically applied formulations. Certain raw materials have been shown to produce follicular hyperkeratosis in the rabbit ear assay. This study quantifies comedogenic potential of cosmetic materials, including: isopropyl palmitate, isopropyl myristate, butyl stearate, isopropyl isostearate, decyl oleate, isostearyl neopentanoate, isocetyl stearate, myristle myristate, cocoa butter, cetyl alcohol, paraffin, stearyl alcohol sodium lauryl sulfate (SLS), and petrolatum. The first nine were deemed positive. Factors aiding clinical relevance are listed.

Acne Cosmetica Revisited: A Case-Control Study Shows a Dose-Dependent Inverse Association between Overall Cosmetic Use and Post-Adolescent Acne

“…The concept of acne cosmetica was proposed by Kligman and Mills in 1972 [3] on the basis of detection of acnegenicity of cosmetics using rabbit ear and human models. Further supportive evidence also came from studies using the rabbit model [4,5,6,7] and human model [8]. These studies showed that the tested cosmetic ingredients have acnegenic effects.…”

“…The concept of acne cosmetica was further strengthened by other studies using a rabbit model [4,5,6,7], a human model [8] or a cross-sectional design [9,10,11,12,13], however, this has not been tested in a case-control design. In the present matched case-control study we examined the association of post-adolescent acne and use of cosmetics and cosmetic procedures.…”

The role of topical dermocosmetics in acne vulgaris

“…However, there may be other options: in a prospective, open‐label, non‐randomized study patients with retinoid dermatitis were either managed with a ethanolic myrtle extract and vitamin gel ( n = 116) or a simple emollient cream ( n = 48) and the combination gel substantially improved overall clinical outcome . Furthermore, dermatologists are now able to refer to lists of substances to avoid in patients with a susceptibility to develop comedones …”

Overcoming the Cutaneous Barrier with Microemulsions

“…Although there are no systematic studies evaluating the comedogenic properties of microemulsions, the effect of several compounds used in these formulations is known. For example, neat isopropyl myristate, isopropyl isostearate, decyl oleate, lauryl alcohol, lanolin and cocoa butter are considered comedogenic with varying intensity [123,124]. Ideally, only non-comedogenic components should be used to claim that a formulation is non-comedogenic, but considering that the effect is influenced by the concentration of a compound, the duration and the frequency of exposure, the properties of the final formulation may actually vary.…”