A vehicle for the evaluation of hydrophobic compounds in cell culture

A vehicle for testing hydrophobic compounds in cell culture has been evaluated on human breast (MCF-7 and MDA-MB-231) and human lung (A 549) cancer cells. The cytotoxicity of the vehicles was evaluated on the basis of cell viability using the hemocytometric trypan blue exclusion method and cell surface morphology using scanning electron microscopy. Dimethylacetamide, absolute ethanol and polyethylene glycol 400 were evaluated as vehicles for solubilizing various hydrophobic compounds. The compounds were found to be most soluble in dimethylacetamide but this solvent was extremely cytotoxic to MCF-7 cells. Similarly, 1% absolute ethanol solubilized the compounds in culture media at a concentration of 10(-5)M, but was also cytotoxic. 0.1% absolute ethanol in the culture media was non-cytotoxic but was unable to solubilize these hydrophobic compounds. Polyethylene glycol 400 was found to be too viscous to use alone. However, upon optimizing the ratio of absolute ethanol and polyethylene glycol 400, a mixture of 45% absolute ethanol plus 55% polyethylene glycol 400 at a final concentration of 0.1% was used as vehicle solubilized the hydrophobic compounds (10(-5)M) in growth media and non-cytotoxic on all the cell lines tested. In conclusion, a vehicle containing a mixture of 45% absolute ethanol plus 55% polyethylene glycol 400 at a final concentration of 0.1% of the growth medium was found to be ideal for testing various hydrophobic compounds in cell culture.