This thesis focuses on the controlled release system of Dapsone (DAP) as the Active Pharmaceutical Ingredient (API) intercalated into sodium montmorillonite (MMT-Na+) and their combination with an anionic copolymer (Eudragit® S100). The effects of the excipients on the API dissolution rate were studied from their release profile in simulated intestinal fluid (pH=7.4) at 37±0.5°C. In the first part of the research, ionizable Dapsone was intercalated in the interlayers of MMT-Na+ to produce a nanohybrid. In the second part of the research, the nanohybrid was melt dispersed in the polymer to produce ternary (API/ Clay/ Polymer) composites. For comparison, API-polymer solid dispersions were prepared by melt mixing in the absence of nanoclay.

The intercalated compound was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and themogravimetric analysis (TGA). The basal spacing of montmorillonite increased from 1.17nm to 1.55nm. The in vitro release experiments revealed that Dapsone was steadily released from MMT. In the second part of the research, an API-polymer miscible system was prepared by melt mixing. In agreement with solubility parameter differences, Dapsone exists in an amorphous state in the polymer matrix. The API-modified clay was dispersed in the polymer to form a ternary system, in which the API showed a more controlled release profile due to the presence of the nanoclay.