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Updated: Feb 7, 2026

An In Vitro Skin Irritation Test SIT using the EpiDerm Reconstructed Human Epidermal RHE Model
Published on: July 13, 2009
Novel Topical Cytokinin Improves Coarse Wrinkles and Skin Roughness Without Skin Irritation
Objective:
To evaluate the efficacy and tolerance of topical 4HBAP (para-topolin [6-(4-hydroxybenzylamino) purine], a new aromatic cytokinin, in subjects with mild to moderate facial photodamage.
Methods:
In this single-center, 12-week study subjects (n=39) applied topical 0.10% 4HBAP (the test article) and sunblock (SPF30) twice daily, in the early morning and in the evening. The efficacy and safety of the treatment were evaluated at study entry (baseline) and at 2, 4, 8 and 12 weeks. Results were evaluated by investigators and subjects using high resolution photography and objectively by transepidermal water loss (skin barrier function), and a Novameter® (skin moisture content).
Results:
Topical 4HBAP significantly improved the appearance of coarse wrinkles after 4, 8, and 12 weeks of continued use without irritating the skin or eliciting erythema. Topical 4HBAP also improved the appearance of fine wrinkles, hyperpigmentation, and skin roughness while significantly reducing facial erythema and the overall severity of acne lesions. The investigators global assessment, the overall severity of skin aging and skin color, showed significant improvement at weeks 8 and 12. Subject-assessed improvements were also highly favorable. In the 25 subjects that had acne at baseline, the number of non-inflammatory lesions and the total number of acne lesions decreased significantly at weeks 8 and 12. Topical 4HBAP significantly increased skin hydration at weeks 2, 8, and 12.
Conclusion:
Topical 4HBAP (0.10%) significantly improves the appearance of fine lines and coarse wrinkles, reduces skin roughness, hyperpigmentation, facial erythema, and non-inflammatory acne lesions, and improves skin hydration without any observed side effects. J Drugs Dermatol. 2018;17(7):772-779.
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