Evaluation of lotion formulations on irritation using the modified forearm-controlled application test method

Abstract

Background/purpose: Cold and allergy sufferers often develop irritation around the nostrils as a result of repeated and frequent rubbing of the skin site with facial tissues. This irritation is a combination of the inherent irritant properties of the tissue components (chemical irritation), and mechanical irritation from friction. Lotion-coated facial tissues are being developed to provide soothing, skin benefits, and to promote healing of this type of irritation. The objective of these studies was to evaluate the efficacy of different lotion formulations on facial tissues in preventing irritation, or aiding in the healing of irritation.

Methods: The modified forearm-controlled application test (Modified FCAT) was adapted as a means of quickly evaluating the relative skin benefits of various lotion formulations used to coat facial tissues. The test was conducted on the volar surface of the forearms of volunteer subjects. Test sites were pretreated with 24 h occlusive patches of sodium lauryl sulfate (SLS) to induce mild or moderate skin irritation. This was followed by repeated wiping of the lotion-coated tissues. Irritation was evaluated using visual scoring for erythema and dryness. Lotion formulation options were compared in the model. Comparisons included assessments of the type of fatty alcohol in the formulation (stearyl and cetearyl alcohol), the presence of silicone and the base formulation (mineral oil, petrolatum of a proprietary formula).

Results: Differences in the degree of erythema and dryness were detected among various formulation options. No differences were found between formulations containing stearyl or cetearyl alcohol. Low levels of silicone produced benefits in one of two experiments. The proprietary base formula produced greater reductions in erythema following treatment of SLS-irritated skin compared with mineral oil and petrolatum bases.

Conclusions: The results indicated that this modification of the FCAT can be used to compare various lotion formulations for skin benefits and healing properties, and to rank qualitatively the benefits of various formulation options.