Toluidine blue loaded transferosomes for topical photodynamic therapy: formulation and characterization

Abstract

Targeted drug delivery systems have distinct advantages over conventional dosage forms. In the present approach, flexible liposomal drug carriers (transferosomes) were formulated and their physicochemical properties were studied compared with conventional liposomal and niosomal formulae. Lipid vesicles composed of lecithin, cholesterol, span 60, and sodium deoxycholate (SDC) were prepared by thin film hydration method. Photodynamic treatment of subcutaneous Ehrlich tumor using prepared and pharmaceutically studied hydrogel containing 1% hydrophilic toluidine blue (TB) loaded transferosomes was evaluated. The results showed that transferosomes containing both span 60 and SDC were of the highest entrapment efficiency (> 82%), particle size (1.36 µm) and released 52% of its content within 2 hours. The in vivo study on BALB/C mice showed that there was a marked increase in the survival time and decrease in the tumor size in mice group treated with transferosomal (span 60 and SDC) hydrogel for 1h followed by irradiation with 90J/cm² from 650 nm diode laser twice weekly compared with animals treated with free TB and irradiated only. Furthermore, there was a marked deep necrosis of tumor cells, which may be attributed to the deep penetration of TB through skin layers. These findings suggest the use of TB loaded transferosomes in topical targeted photodynamic treatment of skin tumors.