Purpose: A new dosage formulation of methotrexate (MTX-CH) was developed to control cancer growth by local administration.
Materials and methods: BALB/c mice received a subcutaneous inoculation with transplantable Colon 26 cancer cells on the back. When cancerous tumor became 7 mm in diameter, MTX-CH or MTX aqueous solution (MTX-sol) was injected into the tumor. The MTX concentration in the tumor was compared between the MTX-CH group and the MTX-sol group. The tumor growth was assessed in single or repeated local administration experiments.
Results: The MTX concentrations were significantly higher for longer periods in the MTX-CH group than those in the MTX-sol group. Repeated MTX-CH administration was significantly more effective for suppressing the tumor growth compared with repeated MTX-sol administration.
Conclusion: MTX-CH is superior to MTX-sol in controlling the tumor growth by local administration because of its long-acting effect.