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

• Published in: Journal of colloid and interface science Vol. 401; pp. 155 - 160
• Main Authors: Siqueira-Moura, Marigilson P., Franceschi-Messant, Sophie, Blanzat, Muriel, Ré, Maria Inês, Perez, Emile, Rico-Lattes, Isabelle, Lattes, Armand, Tedesco, Antonio C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.07.2013; Elsevier
• Subjects: ambient temperature; Charged particles; Chemistry; Chloroaluminum phthalocyanine; Colloidal dispersion; Colloidal state and disperse state; cooling; Dispersions; Droplets; electrostatic interactions; emulsifying; Encapsulation; Engineering Sciences; Exact sciences and technology; gelatinization temperature; Gelation; General and physical chemistry; Hydrophobic and Hydrophilic Interactions; hydrophobicity; Indoles - chemistry; Molecular Structure; Organogel particles; Organometallic Compounds - chemistry; Particle Size; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Physicochemical characterization; Polyetherimides; Polyethyleneimine - chemistry; Self assembly; soybean oil; Soybean Oil - chemistry; Soybeans; Stearic Acids - chemistry; Surface Properties; Temperature; therapeutics; zeta potential; Chloroaluminum phthalocyanine; Physicochemical characterization; Colloidal dispersion; Organogel particles; Characterization; Particle; Oil; Metallophthalocyanine; Hydrophobicity
• DOI: 10.1016/j.jcis.2013.03.029
• ISSN: 0021-9797

[Display omitted] •A new approach to encapsulate a hydrophobic metallophthalocyanine.•Gelled oil particles containing chloroaluminum phthalocyanine (ClAlPc) were developed.•ClAlPc was efficiently encapsulated into gelled soybean oil particles.•Stable gelled particles were obtained using hydroxystearic acid and polyethyleneimine. 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 (Tgel), 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 280nm, homogeneous size distribution (polydispersity index ≈0.3) and large positive zeta potential (about +50mV) 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.