Purpose: To evaluate the use of thermal ink-jetting as a method for dosing drugs onto oral films.
Methods: A Hewlett-Packard printer cartridge was modified so that aqueous drug solutions replaced the ink. The performance of the printer as a function of print solution viscosity and surface tension was determined; viscosities between 1.1 and 1.5 mm(2) s(-1) were found to be optimal, while surface tension did not affect deposition. A calibration curve for salbutamol sulphate was prepared, which demonstrated drug deposition onto an acetate film varied linearly with concentration (r(2) = 0.9992). The printer was then used to deposit salbutamol sulphate onto an oral film made of potato starch.
Results: It was found that when doses were deposited in a single pass under the print head, then the measured dose was in good agreement with the theoretical dose. With multiple passes the measured dose was always significantly less than the theoretical dose. It is proposed that the losses arise from erosion of the printed layer by shearing forces during paper handling. The losses were predictable, and the variance in dose deposited was always less than the BP limits for tablet and oral syrup salbutamol sulphate preparations.
Conclusions: TIJ printing offers a rapid method for extemporaneous preparation of personalized-dose medicines.