Effects of trolamine/sodium alginate topical meulsion on microcomedone formation and dermal sensitization

Journal of Drugs in Dermatology, May, 2008 by Marge Nighland, DR Spey, LB Harrison, D Harrison

Abstract

Background: A topical trolamine/sodium alginate emulsion (TAE) promotes the healing of damaged skin. However, the repeated administration of any topical product increases the potential of contact dermal sensitization and comedogenicity, particularly when applied to the face.

Objective: Two studies to determine whether repeated applications of the TAE induce microcomedones or contact dermal sensitization in healthy volunteers were conducted.

Methods and Materials: For the comedogenicity study, the TAE was applied to the upper back 12 times at 48-hour to 72-hour intervals and compared with negative control sites. Sites were graded for irritation and follicular biopsies were taken. The size and number of microcomedones were assessed. The dermal sensitization study was comprised of 2 phases: an induction phase including 9 applications of the TAE on the left side of the back for approximately 3 weeks; and after a 2-week rest period, a challenge phase in which a single patch application was placed on a new test site, removed 24 hours later, and assessed at 24, 48, 72, and 96 hours.

Results: The difference between the mean comedogenicity scores for the TAE (0.65) and the negative control (0.79) was not statistically significant (P<.05). In the dermal sensitization study, 2 subjects reported low-level, transient reactions graded [+ or -] or 1 (North American Contact Dermatis Group grading scale); 1 subject reported a grade +1 reaction with edema; and another a grade +2 edema reaction. During the challenge phase, 4 subjects exhibited low-level, transient reactions graded [+ or -] or 1.

Conclusions: The topical TAE did not induce clinically significant dermal sensitization or microcomedones in healthy volunteers under repetitive test patch conditions.

Introduction

Considerable attention has been given by dermatologists to the possible comedogenicity of topical medications, cosmetics, and skin care products.(1-4) The concept of "acne cosmetica" has evolved, defined as a form of comedo formation resulting from the use of 1 or more elements of cosmetic or skin care products.(2.4) Acne cosmetica has been described as being similar to postadolescent acne seen in women, which is thought to be related to chronic stress and characterized by closed comedones and scattered papulopustules. Acne cosmetica, however, is more inflammatory and characterized by denser lesions.(5) Among the substances identified as comedogenic are modifications of lanolins and emulsifiers, such as butyl stearate, sodium lauryl sulfate, isopropyl myristate and its analogues, isopropyl palmitate, isopropyl isostearate, isostearyl neopentanoate, and myristyl myristate, among others; as are D & C Red dyes (xanthenes, monoazoanilines, fluorans, and indigoids), and propylene glycol-2 myristyl propionate.(3,6)

Testing of the comedogenic potential of cosmetic products and their ingredients is possible but daunting, given the sheer quantity of both. The testing process is further complicated because finished products containing comedogenic ingredients are not necessarily comedogenic themselves.(2) Testing is typically done with a noninvasive follicular biopsy with a quick-setting polymer to extract the contents of sebaceous follicles. The biopsies are examined histologically to detect lipid components indicative of acne.(7)

The 2 studies reported here evaluated a water-based, topical trolamine/sodium alginate emulsion (TAE; Biafine([R])), which is indicated for use in full-thickness wounds, superficial wounds, first-degree and second-degree burns including sunburns, minor abrasions, dermal ulcers, and graft-site management. When applied to a wound, the TAE provides a moist environment to promote the wound-healing process, which isolates the wound from germs and other external contamination.(8) In addition, the use of the TAE has been reported able to recruit macrophages to wound sites at 3 to 10 times the rate of petrolatum.(9) Comparative trials have shown that TAE applications can increase epithelial cell proliferation, reduce dermal edema, and accelerate wound healing,(9,10) The trials reported here assessed the potential comedogenicity of the TAE and the effect, if any, of dermal sensitization in healthy volunteers.

Methods and Materials

Two separate patch test-type studies, a comedogenicity study and a repeat insult patch test (RIPT), were undertaken to test the effects of a wound-healing topical TAE in healthy volunteers. The first patch-type study evaluated whether repeated applications of the topical TAE induced microcomedones. The second study evaluated the potential of the topical TAE to induce dermal sensitization. Subjects in both studies signed an informed written consent form.

Comedogenicity Study

Study Participants

A minimum of 1.5 subjects, male or female, aged 18 to 45 years, was required for the study. Eligible subjects were required to have at least a 2-week rest period following completion of any previous patch testing, be in good general health, have large visible pores on the back, be acne prone, and willing to participate by following study requirements. Each subject was also expected to complete the full course of the study.

Subjects were excluded if they had atopic skin disease, active psoriasis, and/or active eczema, sunburn, abrasions, scar tissue, or tattoos on the test site, had diseases of the skin that might interfere with the evaluation made in the study or that may expose study participants to unacceptable risks, were currently receiving any anticancer or immunosuppressive treatments, medications, or radiation, or had active or untreated skin cancer, were known to be pregnant, nursing, or planning to become pregnant within the next 6 months, had been using topical steroids and/or drugs on the test sites, used prescription strength anti-inflammatory drugs or high doses of anti-inflammatory drugs for a defined medical condition, used more than 2 aspirin tablets (650 mg) per day, used specific antibiotics and acne medications, such as clindamycin, erythromycin, tetracycline, tretinoin, isotretinoin, benzoyl peroxide, salicylic acid products, or any over-the-counter acne treatment, or had uncontrolled conditions such as hypertension, high cholesterol, thyroid disease, hepatitis, and/or diabetes.