DescriptionTablets is the most convenient way to take medication and 70% of the total medicines are dispensed in the form of tablets. The effectiveness of such dosage form depends on how the drug dissolves in the fluids of the gastrointestinal tract. The dissolution of tablets is dominated by two factors mainly: Wettability of the blends and disintegration of the tablets. The objective of this study consists of: A) Studying the wettability of pharmaceutical blends by droplet penetration method. B) Understanding of the Swelling of pharmaceutical tablets in contact with water. In droplet penetration section, blends of 90% Lactose, 9% APAP, 1% MgSt with varying shear level (0Rev, 160Rev, 640Rev and 1280Rev) were prepared as porous material. To characterize wettability of blends, the penetration profile of both water and silicone oil, which is the volume of droplet versus time, was plotted. The water penetration process consists of three phase: bouncing phase, waiting phase and penetrating phase. By reviewing the penetration model developed by Denesuk, a new method for dynamic contact angle calculation was developed. The results reveal that the wettability of blends decreases as the increasing of shear level. In tablets swelling section, formulations with varying percentage of Avicel and Lactose (80% Avicel-10% Lactose, 45% Avicel-45% Lactose and 10% Avicel-80% Lactose) were used to make tablets with different compaction force ranging from 4KN to 24KN. A experiment was designed to measure the swelling of tablets and mass of water uptake meantime. Both the swelling profile and the water uptake profile of tablets present two behaviors: linear and non-linear, which reveal two possible liquid uptake mechanisms: capillary penetration and particle swelling. Swelling rate and water uptake rate of tablets can be calculated from the swelling profile and water uptake profile. Both of them are non-monotonic with compaction and formulation.