Spray-dried Amioca ® starch/Carbopol ® 974P mixtures as buccal bioadhesive carriers

In the present study, spray-dried Amioca ® starch/Carbopol ® 974P mixtures were evaluated as potential buccal bioadhesive tablets. Carbopol ® (C 974P) concentrations from 5 to 75% were tested. All spray-dried mixtures showed a comparable or better bioadhesive capacity compared to a reference formulation (DDWM/C 974P 95/5). The bioadhesive capacities of Amioca ®/Carbopol ® 974P mixtures were improved by spray-drying. All spray-dried mixtures showed significantly higher work of adhesion values compared to their equivalent physical mixtures. The influence of Carbopol ® concentration on the in vivo adhesion time of placebo tablets and in vitro miconazole nitrate release was tested. The ratio Amioca ®/C 974P 70/30 showed the longest in vivo adhesion time (24.5 ± 8.5 h). Lower and higher C 974P concentrations had a shorter in vivo adhesion time. The mixtures containing between 15 and 30% C 974P could all sustain the in vitro miconazole nitrate release over 20h. Again, lower and higher C 974P concentrations showed a faster in vitro miconazole release. The drug loading capacity of a spray-dried mixture containing 20% C 974P was investigated in vivo in dogs using testosterone as model drug. The spray-dried mixture could be loaded with 60% drug without loosing its in vivo bioadhesive and pharmacokinetic properties.