Gelled oil particles: A new approach to encapsulate a hydrophobic metallophthalocyanine

Marigilson P. Siqueira-Moura (1) , Sophie Franceschi-Messant (2) , Muriel Blanzat (2) , Maria-Inês Ré (3) , Emile Perez (2) , Isabelle Rico-Lattes (2) , Armand Lattes (2) , Antonio C. Tedesco (1)

1 USP - Universidade de São Paulo = University of São Paulo
2 IMRCP - Interactions moléculaires et réactivité chimique et photochimique
3 RAPSODEE - Centre de recherche d'Albi en génie des procédés des solides divisés, de l'énergie et de l'environnement

Chloroaluminum phthalocyanine (ClAlPc) is a promising sensitizer molecule for photodynamic therapy, but its hydrophobicity makes it difficult to formulate. In this study, we have efficiently encapsulated ClAlPc into gelled soybean oil particles dispersed in water. 12-Hydroxystearic acid (HSA) and polyethyleneimine (PEI) were the gelling and stabilizing agents, respectively. The preparation process involved hot emulsification above the gelation temperature (T-gel), followed by cooling to room temperature, which gave a colloidal dispersion of gelled particles of oil in aqueous medium. The gelled particles containing ClAlPc had a medium diameter of 280 nm, homogeneous size distribution (polydispersity index approximate to 0.3) and large positive zeta potential (about +50 mV) and showed a spherical morphology. The gelled oil particle formulations exhibited good physical stability over a 6-month period. ClAlPc interfered with the HSA self-assembly only slightly, and decreased the gelation temperature to a small extent; however it did not affect gelation process of the oil droplets. The amounts of PEI and HSA employed during the preparation allowed us to control particle size and the dispersion stability, a phenomenon that results from complex electrostatic interactions between the positively charged PEI and the negatively charged HSA fibers present on the gelled particles surface. In summary, by using the right ClAlPc, HSA, and PEI proportions, we prepared very stable dispersions of gelled soybean oil particles with excellent ClAlPc encapsulation efficiency. The obtained colloidal formulation of gelled oil particles loaded with ClAlPc shall be very useful for photodynamic therapy protocols.

Mots clés: Chloroaluminum phthalocyanine; Organogel particles; Colloidal dispersion; Physicochemical characterization

Domaines: Sciences de l'ingénieur [physics]

Marigilson P. Siqueira-Moura, Sophie Franceschi-Messant, Muriel Blanzat, Maria-Inês Ré, Emile Perez, et al.. Gelled oil particles: A new approach to encapsulate a hydrophobic metallophthalocyanine. Journal of Colloid and Interface Science, 2013, 401, pp.155-160. ⟨10.1016/j.jcis.2013.03.029⟩. ⟨hal-01688101⟩