Abstract

Present investigation was aimed to prepare economical lactose based directly compressible adjuvant with improved flowability and compressibility. A 32 full factorial design was employed to study the effect of lactose/starch ratio (X1; 50:50,65:35 or 80:20) and the % starch paste (X2; 6,10, or 14 %). Starch paste was prepared by heating the aqueous dispersion of starch at 80o for 15 min. The paste was used to prepare granules. Tablets were prepared on a single stroke tablet machine. The % fines, Carr's index, granular friability, crushing strength and % friability were selected as the dependent variables. Diltiazem HCI and acetaminophen were used as model drugs for evaluating the characteristics of the optimized batch. Medium to high level of both the variables favoured the formation of excellent directly compressible adjuvant. The lactose/starch ratio (X1,) exhibited greatest effect on the crushing strength, Carr's index and tablet friability. As the lactose/starch ratio was increased, Carr's index and crushing strength of the tablets increased and friability of the tablets decreased. The friability of the tablets was inversely related with % of starch paste. A check-point batch was prepared to validate evolved refined models. Good agreement was observed between actual and predicated values of the dependent variables, indicating predictive power of the derived equations. Starch paste prepared by the conventional method yielded weak tablets. Kawakita's and Kuno's parameters suggest that the granules of the check-point batch undergo packing at faster rate than the physical blend of lactose and starch. Up to 30% of acetaminophen could be successfully incorporated into tablets. The crushing strength, friability and disintegration time of diltiazem HCI tablets were found 5.5 kg, 0.5% and 4 min, respectively. Nearly complete release of diltiazem HCI was observed in 15 min in water. The preparative conditions of starch paste determine the product quality. The present study demonstrates the use of experimental design for the preparation of an economical directly compressible adjuvant. The results of multiple regression analysis can be used to predict the effect ofindependent variables on the dependent variables. A product consisting of (lactose/starch ratio-71: 29) exhibited excellent functionality and good tableting characteristics. The developed product The developed product can be explored as an economical alternative to the other lactose based directly compressible adjuvants available in the market