Nitric oxide photorelease from hydrogels and from skin containing a nitro-ruthenium complex

Abstract

Nitric oxide (NO) is a gaseous molecule that has specific functions dictated by its localization and its kinetics of release. As NO-donors have a range of potential uses in the skin, much attention has been paid to the development of topical NO delivery systems. The aim of this work was to study the release rate and the skin penetration of the NO-donor cis-[Ru(NO(2))(bpy)(2)(4-pic)](+) from different gel formulations and their potential as topical NO delivery systems under light stimuli. Among the formulations developed, the anionic gel retarded the nitro-ruthenium complex diffusion and also obstructed NO release after light irradiation. On the other hand, NO release before light irradiation was observed when the complex was dispersed in the cationic chitosan gel, possibly due to oxi-redox reactions between the amino groups of the polymer and the drug molecule. Finally, the non-ionic gel released the NO after light irradiation to the same extent as a drug aqueous solution at the same pH. The drug dispersed in this gel also penetrated into the stratum corneum skin layer, and the nitro-ruthenium complex present in the skin was able to release the NO after light stimuli, suggesting the potential use of this formulation as a topical NO delivery system.

Investigation of a novel trinuclear μ-oxo ruthenium complex as a potential nitric oxide releaser for biological purposes

“…Overall, our results show that compound 1 is a suitable candidate for the development of novel pro-drugs based on the [Ru 3 O(CH 3 COO) 6 ] moiety, both as a carrier and a controlled NO releaser.…”

“…The NO stretching was observed at m(NO) = 1883 cm À1 . This peak is quite symmetrical and is not observed in the precursor [Ru 3 O(CH 3 COO) 6 (3-pic) 2 6 . The value occurs within the typical range for nitrosyl complexes with a linear M-NO coordination, close to the vibrational frequency of free NO (1876 cm À1 ) [44].…”

“…In recent years, the possible applications of metal-nitrosyl compounds in biological systems as potential NO scavengers or releasers, has attracted much attention [1][2][3][4][5][6]. Light irradiation and electrochemical reduction of coordinated NO + are alternatives for the selective release of NO from coordination compounds.…”

“…Besides the rich redox, electrochromic and catalytic properties, species containing labile and/or bridging ligands can act as building blocks to assemble supramolecular structures [18,19,[24][25][26][27][28]. The [Ru 3 O(CH 3 COO) 6 )] moiety also appears as an appealing unit to react with NO 0 . It has been shown that the strong interaction between the unpaired electrons of NO and [Ru III,III,III 3 O] unit accounts for interesting properties [9,10] Recently, our group reported the very first example of a trinuclear ruthenium complex which acts against cancer cells [29].…”

“…In this context, this work presents the synthesis and characterization of the novel complex [Ru 3 O(CH 3 COO) 6 (3-pic)(NO)]PF 6 (1), where 3-pic = 3-methylpyridine, Fig. 1.…”