The effect of starch paste and sodium starch glycolate on the compaction behavior of wet granulated acetaminophen formulations

The effect, of varying the proportion of binder starch paste (SP) and the disintegrant sodium starch glycolate (SSG), on the compaction behavior of wet granulated acetaminophen (ACM) formulations using a fully instrumented rotary tablet press, was studied. Wet granulation formulations were prepared using ACM, SP as binder (equal to 2.5%, 5% or 10% starch concentration), SSG as disintegrant (0%, 4%, 8%, or 12 % w/w), microcrystalline cellulose (MCC) and magnesium stearate (MS) (1.5 % w/w). Upper and lower punch forcedisplacement data during in-die compaction was captured using a fully instrumented rotary tablet press at 13.8 rpm at 96 ± 8, 163 ± 13, 235 ±12 MPa compaction pressures. Elastic energy [EE] and tablet tensile strength was determined as a function of starch and SSG concentration and compaction pressure. At a given compaction pressure, increasing the proportion of SSG resulted in higher values of elastic energy (0.28 to 0.76 Nm with increase in SSG from 0% to 12% at 5% starch and 235 ±12 MPa compaction pressures). The negative effect of SSG on the overall compressibility of granules was due to its high elastic energy and decrease in interparticulate bonding. When examining the elastic energy at increasing SP levels, a decrease in elastic energy was evident (0.60, 0.50 and 0.31 Nm for 2.5%, 5% and 10% starch at 4% SSG and 235 ±12 MPa compaction pressures respectively). At a given composition, an increase in compaction pressure led to an increase in elastic energy (0.15, 0.33 and 0.50 Nm at 4% SSG and 5% starch for 96 ± 8, 163 ± 13, 235 ±12 MPa compaction pressures, respectively). When changing SSG and binder (SP) concentration levels tensile strength was indirectly proportional to elastic energy during compaction. Negative influence of SSG on elastic energy indicated by increased EE and decreased tensile strength and positive influence of SP was evident on lower elastic energy and higher tensile strength of tablets.