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Photoresponsive nanocapsulation of cobra neurotoxin and enhancement of its central analgesic effects under red light

Authors Yang Q, Zhao C, Zhao J, Ye Y

Received 16 January 2017

Accepted for publication 5 April 2017

Published 2 May 2017 Volume 2017:12 Pages 3463—3470


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Dr Lei Yang

Qian Yang, Chuang Zhao, Jun Zhao, Yong Ye

Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, People’s Republic of China

Abstract: Cobra neurotoxin (CNT), a peptide isolated from snake venom of Naja naja atra, shows central analgesic effects in our previous research. In order to help CNT pass through blood–brain barrier (BBB) and improve its central analgesic effects, a new kind of CNT nanocapsules were prepared by double emulsification with soybean lecithin and cholesterol as the shell, and pheophorbide as the photosensitizer added to make it photoresponsive. The analgesic effects were evaluated by hot plate test and acetic acid-induced writhing in mice. The CNT nanocapsules had an average particle size of 229.55 nm, zeta potential of -53.00 mV, encapsulation efficiency of 84.81% and drug loading of 2.98%, when the pheophorbide content was 1% of lecithin weight. Pheophorbide was mainly distributed in outer layer of the CNT nanocapsules and increased the release of the CNT nanocapsules after 650 nm illumination. The central analgesic effects were improved after intraperitoneal injection of CNT at 25 and 50 µg·kg-1 under 650 nm irradiation for 30 min in the nasal cavity. Activation of pheophorbide by red light generated reactive oxygen species which opened the nanocapsules and BBB and helped the CNT enter the brain. This research provides a new drug delivery for treatment of central pain.

Keywords: cobra neurotoxin, nanocapsules, photoresponsive, central analgesic effects, red light, drug delivery, photosensitizer

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