12th International Conference of Pharmaceutical Sciences

Topical delivery of methylene blue (MB) (for photodynamic therapy) and metformin (MET) by dispersions based on monoolein is a therapeutic strategy for the treatment of non-melanoma skin cancer, aiming to minimize systemic toxicity and tumor resistance. However, for adequate skin delivery of both drugs, the outermost barrier of the skin barrier must be overcome; and the development of a system that optimizes the penetration of both drugs and minimizes systemic exposure is interesting. Based on this, the present study evaluated the influence of monoolein(MO)-based dispersions composition on the skin delivery of MB and MET. Dispersions were obtained by the combination of MO (containing or not isopropyl myristate (IPM)), surfactants (Kolliphor P407 (KP) or sodium cholate (CH)) and water, followed by ultrasound homogenization (10 min). MB and MET were added to the system at a concentration of 0.1%, w/w. Aqueous solution of MB and MET (0.1%) was used as control. Skin permeability studies were carried out for 12 hours in diffusion cells using pig ear skin and phosphate buffer pH7.2, as the receptor solution. The results showed that MO/KP dispersion has the potential to enhance skin retention of the MB, as compared to control (p<0,01), but it does not influence on MET skin retention. The combination of IPM with MO/KP dispersion does not influence on skin retention of both drugs, as compared to control; and the substitution of KP in MO dispersion by CH, it does not influence on MB skin retention, but it improves the skin retention of MET, as compared to control (p<0,05). In conclusion, the results suggest that the composition of MO dispersion can influence on skin delivery of the MB and MET; and the combination of CH to the MO/KP dispersion should be evaluated, aiming to improve skin delivery of both drugs.