Photodynamic hydrogel based on Carbomer-TMPyP complex: in vitro release and P.aeruginosa photoinactivation

Cordoba

Congreso; Ricifa; 2021

Ricifa

Photodynamic hydrogel based on Carbomer-TMPyP complex: in vitro release and P.aeruginosa photoinactivation.Luciana Campagno, Ana Apas, Franco Ambrosioni, Alvaro Jimenez-Kairuz, Fabiana AloveroDpto. de Ciencias Farmacéuticas, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba and Unidad de Investigación y Desarrollo en Tecnología Farmacéutica (UNITEFA) ? CONICET. Córdoba ? Argentina.Correspondence: luciana.paula.campagno@unc.edu.ar (L.C) ; fabiana.alovero@unc.edu.ar (F.A.)?Presented at RICiFa 2021 (VI International Meeting of Pharmaceutical Sciences. Córdoba, Argentina. November 10-11-12/2021).Photodynamic antimicrobial chemotherapy is a proposed alternative for localized infections in the age of antibiotic resistance. While topical application of a photosensitizer followed by irradiation is a viable application due to the accessibility of the target site, the desing of an effective and safe delivery systems for the photosensitizer are nevertheless necessary. Previously, we designed hydrogels based on ionic complexes between Carbomer-974P and a cationic porphyrin, TMPyP, which showed slight lower photoinactivation of P.aeruginosa than TMPyP solution. Next, we present studies of in vitro release using Franz-type cells as well as the behavior exhibited in the interaction/association of TMPyP with bacterial cells analyzed by fluorescence microscopy.Release profiles fit better with the zero-order kinetic (R2=0.993) and hydrogel showed a release rate 6.5 times slower than TMPyP solution. Furthermore, a delay in the detection of fluorescent bacteria was observed in hydrogel-treated cultures. Then, the complex behaves as a reservoir of TMPyP, from which it is slowly released by the dissociation of ionic-pairs. This controlled release of TMPyP would modify its bacterial association/internalization kinetics, requiring prolongation of the contact and irradiation period to achieve complete inoculum eradication. However, recognized bioadhesive and rheological properties of carbomer hydrogels allow them to be considered a promising platform for topical photosensitizer delivery systems.Keywords: TMPyP, hydrogels, CLSM, Franz-type cells, Topical controlled release.Funding This research was funded by a grant from SECyT - Universidad Nacional de Córdoba (Res N° 411/18).Conflict of interest. The authors declare no conflict of interest