Enhancement of antiproliferative potential of metformin against melanoma mice B16 cells using an optimized liposomal drug delivery system.

OBJECTIVE: Metformin-loaded liposomes were optimized for enhanced antiproliferative activity against melanoma. METHODS: Box-Behnken design and response surface methodology were employed to optimize entrapment efficiency, ex-vivo permeation and vesicle size. The optimized formulation was prepared by both the lipid hydration method and the modified injection method for comparison. Different concentrations of Pluronic F127 were employed for modification. Selected Pluronic-modified formulation (lipid molar concentration 55 mmol, cholesterol 30% and drug loading 52.9 mg) was characterized for morphology, entrapment efficiency, permeation and vesicle size. RESULTS: The optimized formulation resulted in entrapment efficiency of 41.7 ± 0.01%, vesicle size of 1.405 ± 0.061 µm and percentage of permeation was 67 ± 5.5%. The improved cytotoxic effect of the selected formulation against melanoma mice B16 cell line compared with metformin solution was determined using MTT assay. Compared with the corresponding drug solution, the Pluronic-modified optimized liposomes displayed a highly efficient cytotoxic effect as evidenced by significant lowering in IC50 -887.3 ± 23.2 and 26.71 ± 0.69 µg/ml, respectively, P < 0.0001. CONCLUSION: This study introduces an optimized liposomal formulation with enhanced cytotoxic effect against melanoma B16 cell line.

Metformin-loaded ethosomes with promoted anti-proliferative activity in melanoma cell line B16, and wound healing aptitude: Development, characterization and in vivo evaluation.

The present work deals with the development of metformin-loaded ethosomes for localized treatment of melanoma and wound healing. Different ethosomal formulations were prepared using different concentrations of ethanol adopting injection technique. The developed formulations were investigated for entrapment efficiency, ex-vivo skin permeation, vesicle size, morphology and permeation kinetics. The optimized formulation was loaded in 5 % carbomer gel that was evaluated for skin permeation, cytotoxic effect against melanoma mice B16 cell line and for wound healing action. Ethosomes having 30 % v/v ethanol displayed superior entrapment for metformin % (55.3 ± 0.07); and a highly efficient permeation via mice skin (85.8 ± 3.7). The related carbomer ethosomal gel exhibited higher skin permeation compared to the untreated metformin gel (P < 0.001). The metformin ethosomes had a substantial antiproliferative activity against melanoma B16 cells compared to corresponding metformin solution as shown by the lower IC50 values (56.45 ± 1.47 and 887.3 ± 23.2, respectively, P < 0.05) and tumour cell viability (P < 0.05). The ethosomal system had a significant wound healing action in mice (80.5 ± 1.9%) that was superior to that of the marketed product Mebo® ointment (56 ± 1 %), P < 0.05. This ethosomal system demonstrated outstanding induction of the mRNA levels of growth factors (IGF-1, FGF-1, PDGF-B and TGF-ß) that are essential in the healing process. Those findings were supported by histopathologic examination of wound sections of different treated groups. Thus, the study proved that metformin ethosomes as a promising drug delivery system and a conceivable therapeutic approach for treatment of melanoma and wound healing.