Validation of a quantitative liquid chromatography/hybrid quadrupole-linear ion trap MS/MS method for carfentanil and caffeine in a live human epidermis model.

The method was used to evaluate the percutaneous absorption kinetics of carfentanil in solution as a function of solvent composition using an in vitro, live human epidermis model. Counterintuitively, as previously reported, the addition of organic solvents to the formulations decreased rather than increased the percutaneous absorption rate of the ultra-potent opioid, carfentanil.