Mass transport enhancement by ultrasound in non-degradable polymeric controlled release systems

In this work, an attempt was made to characterize mass transport enhancement in non-erodible polymeric matrices, caused by ultrasound. It was found that drug release rates from polymeric matrices exposed to ultrasound, can be controlled by modifying parameters like: ultrasound frequency, molecular weight of the incorporated drug and structure of the polymeric matrix (size of pores in the network). It is suggested that the enhancing effect of ultrasound on drug release from non-erodible polymers is due to the contribution of a convective term, generated by cavitation, without any destructive effect on morphology of the polymer. This phenomenon was found to be more pronounced in systems which are mass-transport limited. (C) 1998 Elsevier Science B.V.