Comprehensive evaluation of carboxylated nanodiamond as a topical drug delivery system

• Main Authors: Lim DG, Kim KH, Kang E, Lim SH, Ricci J, Sung SK, Kwon MT, Jeong SH
• Format: Article
• Language: English
• Published: Dove Medical Press 2016-05-01
• Series: International Journal of Nanomedicine
• Subjects: Nanodiamond; skin permeation; drug delivery; photo-stability; anti-oxidation.
• Online Access: https://www.dovepress.com/comprehensive-evaluation-of-carboxylated-nanodiamond-as-a-topical-drug-peer-reviewed-article-IJN

Dae Gon Lim,1,* Ki Hyun Kim,1,* Eunah Kang,2 Sun Hee Lim,3 Jeremy Ricci,3 Si Kwon Sung,3 Myoung Taek Kwon,3 Seong Hoon Jeong1 1College of Pharmacy, Dongguk University-Seoul, Gyeonggi, 2School of Chemical Engineering and Material Science, Chung-Ang University, 3NanoResource Co. Ltd., Seoul, Republic of Korea *These authors contributed equally to this work Abstract: The best strategy in the development of topical drug delivery systems may be to facilitate the permeation of drugs without any harmful effects, while staying on the skin surface and maintaining stability of the system. Nanodiamonds (NDs) play a key role with their excellent physicochemical properties, including high biocompatibility, physical adsorption, reactive oxygen species (ROS) scavenging capability, and photostabilizing activity. Z-average sizes of carboxylated ND (ND–COOH) agglutinate decreased significantly as the pH increased. Fluorescein-conjugated ND was observed only on the stratum corneum, and no sample diffused into the dermal layer even after 48 hours. Moreover, ND–COOH and ND–COOH/eugenol complex did not show significant toxic effects on murine macrophage cells. ND improved in vitro skin permeation >50% acting as a “drug reservoir” to maintain a high drug concentration in the donor chamber, which was supported by quartz crystal microbalance results. Moreover, ND–COOH could adsorb a drug amount equivalent to 80% of its own weight. A photostability study showed that ND–COOH increased the photostability ~47% with regard to rate constant of the eugenol itself. A significant decrease in ROS was observed in the ND–COOH and ND–COOH/eugenol complex compared with the negative control during intracellular ROS assay. Moreover, ROS and cupric reducing antioxidant capacity evaluation showed that ND–COOH had synergistic effects of antioxidation with eugenol. Therefore, ND–COOH could be used as an excellent topical drug delivery system with improved permeability, higher stability, and minimized safety issue. Keywords: nanodiamond, skin permeation, drug delivery, photostability, anti-oxidation