Clinical Evaluation of the Human Tyrosinase Inhibitor Thiamidol (isobutylamido thiazolyl resorcinol) in Prevention of UVB-induced Hyperpigmentation

Main Article Content

Vasanop Vachiramon
Chaninan Kositkuljorn
Kanchana Leerunyakul
Kumutnart Chanprapaph
Daniel Romanowitz

Keywords

Thiamidol, Hyperpigmentation, UVB

Abstract

Clinical Evaluation of the Human Tyrosinase Inhibitor Thiamidol (isobutylamido thiazolyl resorcinol) in Prevention of UVB-induced Hyperpigmentation


Vasanop Vachiramon, Chaninan Kositkuljorn, Kanchana Leerunyakul, Kumutnart Chanprapaph


Division of Dermatology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand


Background: Thiamidol (isobutylamido thiazolyl resorcinol) has been identified as a potent human tyrosinase inhibitor. A formulation containing Thiamidol has recently shown promising efficacy for the treatment of some hyperpigmentation conditions.


Objectives: This study aimed to evaluate the efficacy and safety of a Thiamidol-based formulation in the prevention of ultraviolet (UV)-induced hyperpigmentation.


Materials and Methods: We performed a randomized, single-blinded, pilot study in healthy participants, N=30. One arm was randomly assigned to receive a Thiamidol-based formulation for three weeks. Three hyperpigmented spots were induced by UVB irradiation on both arms after 3 weeks of ITR application. Outcome evaluations included measuring mean lightness index (*L) obtained by colorimeter, hyperpigmentation scores by visual analog scale (VAS), and adverse effects.


Results: Both experimental sides showed no significant difference in terms of skin lightening after Thiamidol application. However, the Thiamidol-treated sides showed a statistically significant lower mean lightness index compared to control after an induction with UVB. In addition, the Thiamidol-treated sides had an earlier improvement and resumed normal skin color after 3 weeks post-UVB induction. A clinical evaluation by a blinded non-treating physician and subjects was more favorable on the Thiamidol-treated side than the control side (P < .05). No significant side effect was noted.


Conclusions: Thiamidol is an effective agent in the prevention of pigmentary change from UVB irradiation and may serve as a promising agent for preventing other hyperpigmentation conditions.

References

1. Kumari S, Thng S, Verma N, Gautam H. Acta Derm Venereol. 2018;98(10):924-931.

2. Brenner M, Hearing VJ. Drug Discov Today Dis Mech. 2008;5(2):e189-e199.

3. Shah S, Alster TS. Am J Clin Dermatol. 2010;11(6):389-397.

4. Grimes PE. Semin Cutan Med Surg. 2009;28(2):77-85.

5. Mann T, Gerwat W, Batzer J, et al. J Invest Dermatol. 2018;138(7):1601-1608.

6. Arrowitz C, Schoelermann AM, Mann T, Jiang LI, Weber T, Kolbe L. J Invest Dermatol. 2019;139(8):1691-1698.

7. Mohania D, Chandel S, Kumar P, et al. Adv Exp Med Biol. 2017;996:71-87.

8. Kim H, Choi HR, Kim DS, Park KC. Ann Dermatol. 2012;24(1):1-6.

9. O’Donoghue JL. J Cosmet Dermatol. 2006;5(3):196-203.

10. Westerhof W, Kooyers TJ. J Cosmet Dermatol. 2005;4(2):55-59.

11. Pyo JJ, Ahn S, Jin SH, et al. Arch Toxicol. 2019;93(8):2307-2320.

12. Park KT, Kim JK, Hwang D, Yoo Y, Lim YH. Food Chem Toxicol. 2011;49(12):3038-3045.

13. Espín JC, Varón R, Fenoll LG, et al. Eur J Biochem. 2000;267(5):1270-1279.

14. Kolbe L, Mann T, Gerwat W, et al. J Eur Acad Dermatol Venereol. 2013;27(Suppl 1):19-23.

15. Mann T, Scherner C, Röhm KH, Kolbe L. Int J Mol Sci. 2018;19(3):690.

16. Hariharan V, Klarquist J, Reust MJ, et al. J Invest Dermatol. 2010;130(1):211-220.

Most read articles by the same author(s)