Release of sodium fusidate from glass-ionomer dental cement

Restorative grade glass-ionomer cement has been studied for its potential as a controlled release material for the antimicrobial compound sodium fusidate. Sodium fusidate powder was incorporated into the cement at the mixing stage at levels of 1% and 5% by mass, and disc shaped specimens (6 mm diameter x 2 mm depth) prepared. After curing for 1 hour at 37 degrees C, specimens were placed in water and release of sodium fusidate at set time intervals determined using reverse-phase HPLC. Sets of five specimens were used in all experiments. Early release of sodium fusidate was shown to occur by diffusion for each level of addition, as shown by M(t)/M(infinity) being linear with respect to [square root]time in both cases. Diffusion coefficients were calculated as 4.4 x 10(-8) cm(2) s(-1) and 3.0 x 10(-8) cm(2) s(-1) for 1 and 5% respectively. These were an order of magnitude lower than had been found previously for water transport in glass-ionomer cements, a result that is attributed to the greater size of the sodium fusidate molecule compared with that of water. Cements released 20.4 and 22.8% respectively of the total sodium fusidate added after 2 weeks, values which were not significantly different from each other, and which exceeded total release previously reported for benzalkonium chloride and chlorhexidine.