Excited-state dynamics of imiquimod in aqueous solutions

Takkella, D. and Sharma, S. and Gavvala, K. and et al, . (2022) Excited-state dynamics of imiquimod in aqueous solutions. Journal of Photochemistry and Photobiology A: Chemistry, 431. pp. 1-7. ISSN 1010-6030

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Imiquimod, commonly formulated as AldaraTM, is one of the most widely used drugs in clinic to treat several skin diseases such as superficial basal cell carcinoma (BCC), viral warts, etc. As this kind of important skin drugs tends to be exposed to light the characterization of their photophysical properties would help to further scrutinize the molecule's biological activity. Herein, for the first time we characterize the photophysical and acid-base properties of Imiquimod in aqueous solutions using different spectroscopic techniques and quantum chemical calculations. Steady-state spectroscopy revealed that the drug molecule can exist in three different forms depending upon pH of the medium. The excited-state lifetimes of these three distinct forms of IMQ were well characterized by using time-resolved spectroscopic technique. Quantum chemical calculations confirm the molecular structures of the three forms as cationic, neutral and anionic forms of IMQ that are observed in different pH conditions. A unique excited state phenomenon is observed at higher pH, where the neutral form of the drug is being converted to anionic form exclusively in the excited state via excited state proton transfer mechanism. © 2022 Elsevier B.V.

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Item Type: Article
Additional Information: K.G. is thankful to the Science and Engineering Research Board (SERB – SRG/2020/000248), Government of India for the generous research grant. D.T. is thankful to the University Grants Commission (UGC) for the research fellowship. Authors thank Indian Institute of Technology Hyderabad for providing the research facilities. L. M.F. thanks the CCC-UAM for generous allocation of computing time and the Madrid Government (Comunidad de Madrid-Spain) under the Multi- annual Agreement with Universidad Aut ́onoma de Madrid in the line Support to Young Researchers, in the context of the V PRICIT (Regional Programme of Research and Technological Innovation) (SI3/PJI/2021- 00331)
Uncontrolled Keywords: Dynamics, Excited state proton transfer, Imiquimod, Time-resolved spectroscopy, Vertical emission energies
Subjects: Chemistry
Divisions: Department of Chemistry
Depositing User: . LibTrainee 2021
Date Deposited: 17 Jun 2022 11:34
Last Modified: 22 Jun 2022 07:40
URI: http://raiith.iith.ac.in/id/eprint/9307
Publisher URL: https://doi.org/10.1016/j.jphotochem.2022.113998
OA policy: https://v2.sherpa.ac.uk/id/publication/12834
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