Development and optimization of gastro retentive floating tablets of dapsone for controlled release

The objective of this study was to develop and optimize gastroretentive floating tablets of dapsone using a Quality by Design approach to enhance therapeutic efficacy in leprosy treatment. The tablets were prepared by direct compression using a 3² factorial design, with HPMC K15M (150–250 mg) and NaHCO3 (15–25 mg) as independent variables. The formulations were evaluated for compression parameters, floating characteristics, and drug release profiles, with optimization focused on floating lag time (Y1) and drug release at 12 hours (Y2) as key responses. Further studies assessed release kinetics, formulation stability, and comparison with a marketed product. The optimized formulation (RF3), composed of 150 mg HPMC K15M and 25 mg NaHCO3, exhibited excellent flow properties (Carr’s index: 15.25%, angle of repose: 26.84°), desirable floating behaviour (lag time: 64 seconds, duration: 11.4 hours), and sustained drug release (98.4% over 12 hours). The drug release followed the Higuchi model (R² = 0.9975) with a non-Fickian transport mechanism (n = 0.75). Stability studies under accelerated conditions (40 °C/75% RH for 6 months) confirmed drug content retention of 98.24% and a consistent release profile (97.4% at 12 hours). Overall, the optimized gastroretentive floating tablet formulation demonstrated satisfactory in vitro performance and stability, suggesting promising advantages over conventional dosage forms through extended gastric retention and controlled drug release. While these findings support the potential of this novel formulation for modified dapsone delivery, comprehensive in vivo studies are necessary to validate its therapeutic benefits over existing therapies.