Anthralin. Different concentration effects on epidermal cell DNA synthesis rates in mice and clinical responses in human psoriasis

Abstract

There had been recent interest in psoriasis treatment regimens with low anthralin concentrations of 0.01% and 0.05%. These regimens used salicylic acid, coal emollient baths, and ultraviolet energy. We were interested in evaluating the effects of different concentrations of anthralin without adjunctive therapy. We studied the effects of anthralin on epidermal cell DNA synthesis in hairless mice and found that, in concentrations between 0.1% and 0.4%, anthralin produced significant suppression. However, 0.05%, 0.025%,and 0.01% anthralin failed to inhibit DNA synthesis. Clinical studies of 0.05% and 0.1% anthralin in a water-in-soil emulsion (Eucerin) were performed on 14 patients with psoriasis. Psoriasis severity was scored before and during the period of anthralin use and showed a significant improvement in 0.1% anthralin-treated sites. No significant differences were noted between 0.05% anthralin-treated areas and those areas treated with the vehicle alone.

The effect on epidermal DNA synthesis of a combination of topical steroid with either dithranol or tar as used for psoriasis

“…Several important practical points arise from this study. The results obtained using dithranol solution confirm those of Lowe & Breeding (1981) using a similar hairless mouse model. It is of interest that there is no significant local inhibition of epidermal DNA synthesis at concentra-tions below o 05% since this supports accepted clinical practice that such low concentrations of dithranol are therapeutically ineffective.…”

In Search for New Antipsoriatic Agents: NAD⁺ Topical Composition

“…Usually, this agent is applied in increasing concentrations from 0.05 to 4%. Comparative studies demonstrated its efficacy also in a low -0.1% concentration [23] . Low-strength formulations are not only active, as also confirmed by light microscopy, transmission electron and scanning electron microscopy, but also less irritating and staining [24] .…”

The pharmacological variability of crude coal tar

“…Those sublot fractions sampled appear to maintain their pre-process levels of epidermal DNA synthesis suppression without depletion or amplification of those components which are responsible for suppression activity The variability displayed between two distillations of crude coal tar and even among fractions of a single distillation is demonstrated by the hairless mouse epidermal DNA synthesis suppression assay. This technique was used because of the high correlation between activity in this assay and clinical efficacy (Lowe & Breeding, 1981;Lowe et al, 1981b). Based on these previous studies, variations in DNA synthesis suppression as demonstrated by crude coal tars in Fig.…”