Evaluation of cytotoxicity of oils used in coenzyme Q10 Self-emulsifying Drug Delivery Systems (SEDDS).

The objective of the present study was to develop a suitable method for evaluation of cytotoxicity of the oils used in Self-Emulsified Drug Delivery Systems (SEDDS) using Coenzyme Q10 (Co Q10) as a model compound. For this purpose, three methods of sample preparation were tested, namely (i) suspensions, (ii) homogenization, and (iii) nanoemulsions of oils in Dulbecco's Modified Eagle's Media (DMEM). Studies were carried out by incubating the sample or control with Caco-2 cells grown on transwell insert systems as well as in flat bottom 96-well plates. The cell viability was assessed by using WST-1 and propidium iodide reagents while the monolayer integrity was assessed by mannitol permeability and Trans Epithelial Electrical Resistance (TEER). The cytotoxicity of oils was found to be dependent on the method of sample preparation; nanoemulsions being the least cytotoxic. In conclusion, nanoemulsification is a useful tool for cytotoxicity evaluation of substances, which exhibit poor aqueous/dimethyl sulfoxide (DMSO) solubility.