In this work we have developed
nanocapsules containing
chloroaluminum phthalocyanine (ClAlPc) and assessed their phototoxic action on WM1552C, WM278, and WM1617 human
melanoma cell lines. The ClAlPc-loaded
nanocapsules were prepared by the nanoprecipitation method and optimized by means of a 2(3) full factorial design. The ClAlPc
nanocapsules were characterized by particle size and distribution, zeta potential, morphology, encapsulation efficiency,
singlet oxygen production, stability, and phototoxic action on
melanoma cells. Both the development and optimization studies revealed that stable colloidal formulations could be obtained by using 1.75% (w/v) soybean
lecithin, 1.25% (w/v)
Poloxamer 188, 2.5% (v/v)
soybean oil, and 0.75% (w/v)
poly(D,L-lactide-co-glycolide). The
nanocapsules had a mean diameter of 230 nm, homogeneous size distribution (polydispersity index<0.3), and negative zeta potential (about -30 mV). Their morphology was spherical, with evident
polymer membrane coating droplet. The encapsulation efficiency was 70%, as expected for hydrophobic drugs, and the nanoencapsulated ClAlPc was able to produce high
singlet oxygen quantum yield. ClAlPc
nanocapsules exhibited good physical stability over a 12-month period. WM1552C primary
melanoma cells were more sensitive (p<0.05) to the phototoxic effect elicited by ClAlPc
nanocapsules (0.3 μg ml(-1)) under light irradiation at 20 mJ cm(-2). On the other hand, the cell survival percentage for all the
melanoma cell lines treated with the highest light dose (150 mJ cm(-2)) was lower than 10%. In summary, ClAlPc nanoencapsulation could enable application of this hydrophobic
photosensitizer in the treatment of
malignant melanoma with the use of both low sensitizer
drug concentration and light dose.