Saman Heydari
1 
, Mohammad Barzegar-Jalali
2, Mostafa Heydari
3, Afsaneh Radmehr
4, Ana Cláudia Paiva-Santos
5,6, Maryam Kouhsoltani
7, Hamed Hamishehkar
8* 1 Student Research Committee and Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
2 Biotechnology Research Center and Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
3 Department of Pharmaceutical Nanotechnology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
4 Department of Dermatology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
5 Department of Pharmaceutical Technology, Faculty of Pharmacy of the University of Coimbra, University of Coimbra, 3000-548 Coimbra, Portugal
6 REQUIMTE/LAQV, Group of Pharmaceutical Technology, Faculty of Pharmacy of the University of Coimbra, University of Coimbra, 3000-548 Coimbra, Portugal
7 Department of Oral and Maxillofacial Pathology, School of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran
8 Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Abstract
Introduction: Follicular delivery is one of the targeted drug delivery methods aiming to target the hair follicles. The accumulation and retention time of targeted drugs is enhanced when nanoparticles are used as drug carriers. Particle size is one of the important factors affecting the penetration and accumulation of particles in the hair follicles, and there is a controversy in different studies for the best particle size for follicular delivery. Mouse models are mostly used in clinical trials for dermal, transdermal, and follicular delivery studies. Also, it is essential to investigate the reliability of the results between human studies and mouse models.
Methods: Curcumin-loaded nanostructured lipid carriers (NLCs), as a fluorescent agent, with three different particle size ranges were prepared using the hot homogenization method and applied topically on the mouse and human study groups. Biopsies were taken from applied areas on different days after using the formulation. The histopathology studies were done on the skin biopsies of both groups using confocal laser scanning microscopy (CLSM). We compared the confocal laser scanning microscope pictures of different groups, in terms of penetration and retention time of nanoparticles in human and mouse hair follicles.
Results: The best particle size in both models was the 400 nm group but the penetration and accumulation of particles in human and mouse hair follicles were totally different even for the 400 nm group. In human studies, 400 nm particles showed good accumulation after seven days; this result can help to increase the formulation using intervals.
Conclusion: The best particle size for human and mouse follicular drug delivery is around 400 nm and although mouse models are not completely suitable for follicular delivery studies, they can be used in some conditions as experimental models.