With the aid of permanent cultured MDCK (Madin Darby Canine Kidney) ep
ithelial cell a model for investigations dealing with phonophoresis ef
fects was developed. The permeation of procaine hydrochloride through
cell monolayers was examined while applying therapeutical ultrasound s
imultaneously. It could be shown that this permeation follows Higuchi
kinetics. A comparison of the velocity factors, using a continous irra
diation of 1.0 W/cm(2), shows about a 4.8fold increase. Single Ultraso
und pulses, however, result in a short-time enhancement of the permeat
ion. The conclusion can be drawn that extent and velocity of the perme
ation of procaine hydrochloride through MDCK monolayer can be controll
ed by phonophoresis.