Efficient brain uptake of piperine and its pharmacokinetics characterization after oral administration.

1. Piperine, the major biological active component in black pepper has been associated with miscellaneous pharmacological effects, especially on central nervous system. To correlate with its neurological activity, a comprehensive pharmacokinetic profile of piperine in brain, plasma and cerebrospinal fluid after oral administration in rats was investigated in this study. 2. It was noted that piperine could efficiently penetrate and homogeneously distribute into brain with similar pharmacokinetics profiles in each region. In addition, piperine concentrations in brain and plasma were found to be comparable with brain to plasma area under curve extrapolated to infinity (AUC0→∞ ) ratios of 0.95 and 1.10 for total concentration and unbound concentrations, respectively. Piperine also demonstrated high affinity toward brain tissue (98.4-98.5%) and plasma protein (96.2-97.8%) leading to a brain distribution volume of 36.32 ± 1.40 ml/g brain. Moreover, its efficient membrane permeability (Papp values of 5.41  ±  0.40 × 10- 5 cm/s and 4.78  ±  0.16 × 10- 5 cm/s for basolateral to apical and apical to basolateral transport in Caco-2 monolayer model) and limited hepatic metabolism (Clint of 8.15 μl/min/mg) could also contribute to its quick and high extent brain exposure. 3. In summary, this study for the first time demonstrated high brain penetration potency of piperine could be resulted from its high brain tissue affinity and membrane permeability together with its limited liver metabolism.