Tablet disintegration,generally, is a requirement prior to dissolution. To promote the dissolution, a tablet should rapidly disintegrate into fine particles. In so doing, a disintegrant is usually repuired in the formulation. In search of a new disintegrant, mung starch was extracted from mung bean Phaseolus aureus Roxb. Mung starch was further modified to pregelatinized mung starch (MPS), 2 hourly cross-linked mung starch (MCS2), and 4 hourly cross-linked mung starch (MCS4). The efficienby of these starches were evaulatied at 2% level in hydrochloro-thiazide (HCTZ) direct compression formulation containing Emcompress (R) (ECP) as a tablet filler. MCS2 was found to be superior to corn, mung and other modified mung starches regarding the overall tablet properties, especially the disintegrationand dissolution. The order of dissolution rate was MCS2 > MPS > MCS4 > corn starch > mung starch. MCS2 was chosen for further study. The optimun concentration of MCS2 was determined in both direct compression and wet granulation formulation. In the former case, MCS2 was evaluated at 0.5, 1 and 2% level. Regardless of the fillers tested, i.e., ECP and Tablettose (R), the results indicatied that 2% gave the most satisfactory disintegration and dissolution characteristics. In the latter case, MCS2 was evaluated at 1 and 2% level. Dicalcium phosphate dihydrate and lactose were employed in different formulations. Starch pasts was used as tablet binder. It was found that 1 and 2% MCS2 gave comparable. The study of physical and chemical properties of MCS2 revealed that 92% by weight of MCS2 was carbohycrate. The amlylose content was approximately 40%

the high amylose content was probably responsible for the disintergability of MCS2. The swelling of MCS2 was markedly greater than the unmodified starches. It could be concluded that MCS2 was one of the most efficient disintegrants. MCS2 at 2% level would give satisfactory results in any formulation.