New pectin-based hydrogel containing imiquimod-loaded polymeric nanocapsules for melanoma treatment.

Abstract

We developed a pectin-based hydrogel containing nanocapsules as a new strategy for melanoma treatment. Our first objective was to evaluate the nanoencapsulation effect of imiquimod on melanoma. Imiquimod-loaded polymeric nanocapsules (NCimiq) showed significant time-dependent decrease in cell viability after treatment at 3μmolL-1 (79% viable cells in 24h and 55% in 72h), which was not observed in cells treated with the solution of the drug (IMIQ) (99% viable cells in 24h and 91% in 72h). The second objective was to develop the hydrogel containing the drug-loaded nanocapsules (PEC-NCimiq). In vitro release study showed that 63% of imiquimod was released from the pectin-based hydrogel containing the drug (PEC-imiq) after 2h, while 60% of the drug was released from PEC-NCimiq after 8h. In the permeation study, 2.5μg of imiquimod permeated the skin within 8h after the initial contact of PEC-NCimiq, whereas only 2.1μg of drug permeated after 12h of contact when PEC-imiq was assayed. Pectin-based hydrogels enabled the drug penetration in all skin layers, especially the dermis (PEC-NCimiq = 6.8μg and PEC-imiq = 4.3μg). In the adhesion study, PEC-NCimiq showed the highest adhesiveness (42% removed from the skin) in comparison to PEC-imiq (71% removed from the skin). In conclusion, the nanoencapsulation provided a higher cytotoxic effect of imiquimod in SK-MEL-28, and the incorporation of the drug-loaded nanocapsules in pectin-based hydrogel showed higher adhesiveness and deeper penetration of the drug into the skin. Graphical abstract.