Description and preliminary evaluation of a new ultrasonic atomizer for spray-congealing processes

A new atomizer that operates with ultrasonic energy is described. This appa ratus is intended to obtain microparticulate drug delivery systems through spray-congealing or spray-drying technologies. In this work, some experimen tal results are reported on model systems submitted to spray-congealing. Th e formulations tinder examination contained theophylline and fenbufen as mo del drugs and stearic acid, carnauba wax, Cutina HR(R) and Compritol 888 AT O(R) as low melting excipients. Non-aggregate and spherical-shaped micropar ticles were obtained with all the materials tested, moreover. they had smoo th surface and good flowability. The particle sizes depend on the amount of drug present and in each case the maximum size value of the distribution f requency was found to be 375 mu. In vitro release of the drug depends on it s solubility and on the excipient lipophilicity. The results suggest that t he ultrasound-assisted atomizer could be proposed as a possible alternative to traditional atomizers used for spray-congealing in the: pharmaceutical field. (C) 1999 Published by Elsevier Science B.V. All rights reserved.