Formulation of Aluminum Chloride Phthalocyanine in Pluronic^™ P‐123 and F‐127 Block Copolymer Micelles: Photophysical properties and Photodynamic Inactivation of Microorganisms

Abstract

Aluminum Chloride Phthalocyanine (AlPcCl) can be used as a photosensitizer (PS) for Photodynamic Inactivation of Microorganisms (PDI). The AlPcCl showed favorable characteristics for PDI due to high quantum yield of singlet oxygen (ΦΔ ) and photostability. Physicochemical properties and photodynamic inactivation of AlPcCl incorporated in polymeric micelles of tri-block copolymer (P-123 and F-127) against microorganisms Staphylococcus aureus, Escherichia coli and Candida albicans were investigated in this work. Previously, it was observed that the AlPcCl undergoes self-aggregation in F-127, while in P-123 the PS is in a monomeric form suitable for PDI. Due to the self-aggregation of AlPcCl in F-127, this formulation did not show any effect on these microorganisms. On the other hand, AlPcCl formulated in P-123 was effective against S. aureus and C. albicans and the death of microorganisms was dependent on the PS concentration and illumination time. Additionally, it was found that the values of PS concentration and illumination time to eradicate 90% of the initial population of microorganisms (IC90 and D90 , respectively) were small for the AlPcCl in P-123, showing the effectiveness of this formulation for PDI.

Engineering of relevant photodynamic processes through structural modifications of metallotetrapyrrolic photosensitizers

“…A similar effect was recently reported for a Zn 2+ coordinated phthalocyanine formulated in F127 and P123 [199]. Our results also indicate that modification of photosensitizer via incorporation into Pluronic P-123 micelles led not only to an improved stability and ROS generation, but also to the increased selectivity towards tumor tissue, enhanced local inflammation and significant antitumor response after its excitation with near-infrared light (NIR).…”

“…In vitro cytotoxicity studies on mouse colon tumor (CT26) cell line demonstrated the enhanced internalization and photoactivity of encapsulated Ce6. Vilsinski and co-workers described physicochemical properties and photoactivity of aluminum chloride phthalocyanine (AlPcCl) incorporated into Pluronic P123 and F127 [199].…”

“…Since then Pluronic micelles have been widely investigated and, as a consequence, considered as promising carriers also for other photosensitizers, such as porphyrins, xanthenes, chlorins and phthalocyanines [198][199][200]. Chlorin e6 conjugates with Pluronic F127 ® were synthesized and characterized by H. Park and K. Na [201].…”

Porphyrins Encapsulated into Pluronic F127 Micelles: Evaluating the Effect of the Central Metal and Substituents on the Photophysicochemical Properties in Water

“…[1] Polymer micelles also have the ability to solubilize water insoluble anticancer drugs such as porphyrins which are a subject of the current work. [2] The polymeric micelles of interest in this work are the Pluronic triblock copolymers which are composed of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) with a PEO-PPO-PEO structure (Scheme 1).…”

“…[3] Due to their biocompatibility and high drug loading ability, several Pluronics have been approved by Food and Drug Administration (FDA) for oral or intravenous administration because they are widely employed as solubilizers, emulsifiers or coating agents. [1,[4][5][6] Porphyrins have poor solubility [7] and are also known to aggregate, [8] which affects their photophysical behaviour. The driving forces behind the aggregation of porphyrins are the cooperative formation of hydrogen bonds, van-der-Waals forces and the hydrophobic effects.…”