Least absorbed from mucous membrane are

Hydrophobicity is a primary determinant of intrinsic anesthetic potency because the anesthetic molecule must penetrate into the nerve membrane and bind at a paially hydrophobic site on the Na+ channel. Clinically, however, the correlation between hydrophobicity and anesthetic potency is not as precise as in an isolated nerve. Differences between in vitro and in vivo potency may be related to a number of factors, including local anesthetic charge and hydrophobicity (which influence paitioning into and transverse diffusion across biologic membranes) and vasodilator or vasoconstrictor propeies (which influence the initial rate of vascular uptake from injection sites into the central circulation). Ref: Miller's anesthesia 8th edition Ref: Morgan & Mikhail's clinical anesthesiology 6e