Physical methods associated with liposomes and immunoliposomes improve the topical delivery of Chloroaluminum Phthalocyanine.

Chloroaluminum phthalocyanine (ClAlPc), a promising photosensitizer for photodynamic therapy (PDT), faces challenges owing to its lipophilic nature and aggregation in aqueous media. This study aimed to develop and characterize immunoliposomes containing ClAlPc and oleic acid for targeted PDT of squamous cell carcinoma (SCC), which overexpresses epidermal growth factor receptor (EGFR). The study also evaluated the influence of physical methods (microneedles and sonophoresis) on promoting the skin penetration of ClAlPc. The liposomes composed of soybean phosphatidyl choline, cholesterol, oleic acid, and DSPE-PEG(2000) were characterized using Atomic Force Microscopy (AFM) and conjugated with cetuximab, an anti-EGFR antibody, achieving an encapsulation and conjugation efficiency of 71.24 % and 66.12 % for ClAlPc and cetuximab, respectively. The antibody demonstrated structural integrity after polyacrylamide gel electrophoresis (SDS-PAGE) and thermophoresis analyses. In vitro studies in EGFR-positive cell lines (A431) demonstrated greater cytotoxicity of immunoliposomal ClAlPc compared to the free ClAlPc solution, with effects dependent on treatment time and concentration. In vitro skin penetration studies demonstrated that ClAlPc encapsulation in both liposomes and immunoliposomes enhanced skin permeation. In all groups evaluated, a statistically significant difference was observed when compared to the ClAlPc solution, for sonophoresis. Furthermore, the impact of microneedling on the skin penetration of ClAlPc was investigated, revealing a two-fold increase in penetration into the viable epidermis. Mathematical modeling of drug diffusion from liposomes in the skin corroborated the formulation's retention behavior and slow diffusion, which is ideal for topical application (R² = 0.94, Dsc = 1.78x10-11m²/h). These results demonstrate the successful development of a targeted liposomal delivery system for ClAlPc, highlighting its potential for enhanced PDT of EGFR-overexpressing carcinomas, particularly when combined with skin penetration enhancement techniques.