Delivery of 5-aza-2´-deoxycytidine (decitabine) across porcine buccal mucosa was evaluated as an alternative to the complex intravenous infusion regimen currently used to administer the drug. A reproducible high-performance liquid chromatography method was developed and optimized for the quantitative determination of this drug. Decitabine showed a concentration-dependent passive diffusion process across porcine buccal mucosa. An increase in the ionic strength of the phosphate buffer from 100 to 400 mM decreased the flux from 3.57 ± 0.65 to 1.89 ± 0.61 μg/h/cm 2 . Trihydroxy bile salts significantly enhanced the flux of decitabine at a 100 mM concentration (P 9 .05). The steady-state flux of decitabine in the presence of 100 mM of sodium taurocholate and sodium glycocholate was 52.65 ± 9.48 and 85.22 ± 7.61 μg/cm 2 /h, respectively. Two dihydroxy bile salts, sodium deoxytaurocholate and sodium deoxyglycocholate, showed better enhancement effect than did trihydroxy bile salts. A 38-fold enhancement in flux was achieved with 10 mM of sodium deoxyglycocholate.