| Two direct-compression formulation blends of guaifenesin (25% and 40% w/w) were prepared for the study. Silicified microcrystalline cellulose (SMCC) and Magnesium stearate (Mg.St., 0.5% w/w) were used as diluent/filler and lubricant, respectively. Guaifenesin and SMCC were de-clumped by independently passing through a sieve (mesh # 40), and blended in a twin-shell blender (V-blender) at 20 RPM for 10 min. Mg.St. was added to this blend after passing through a sieve (mesh # 60), and further blended for 2 min. The true densities of the formulations were measured using a helium pycnometer (ULTRAPYC 1200e) using the method specified in the USP38-NF33. The tablets of both formulations were prepared on an instrumented, 10-station, single-layer, rotary tablet press (Model: Piccola B-506, SMI Inc., Lebanon, NJ) using 10mm, flat-faced, 'B' tooling, and 8-station, single-layer press, rotary tablet press (Model: Piccola D-190, SMI Inc., Lebanon, NJ) using 10mm, flat-faced, `D' tooling. Both formulations were compressed using five different head flats (HF) i.e. No HF, 50% HF, Standard HF, Extended HF, and 0.875 HF (0.625 HF for `B' tooling). The target compact weight was set at 300 mg. The compacts were prepared at a constant tableting speed of 50RPM, at compression forces (CF) ranging from 525KN, in 5 KN increments. The tableting speed and the compression forces were monitored live using real-time display from the accompanied software. The prepared tablets were evaluated for dimensions, weight variation, breaking force (BF), friability, and capping index. The results were statistically evaluated using one-way ANOVA between groups and For both formulations, tablets prepared using `D' tooling showed a significantly (p<0.05) higher BF compared to those prepared using `B' tooling, likely due to higher dwell times associated with `D' tooling. Formulations containing 25% w/w guaifenesin showed a significantly (p<0.05) higher BF compared to those containing 40% w/w guaifenesin, irrespective of the given CF, punch head flat type, or tooling type. This could be due to the higher ratio of PROSOLVRTM SMCC contributing to the compressibility.;For both formulations compressed using `B' tooling, differences in BF profiles were observed between different head flats. The differences were more pronounced between the low flat heads (no HF, 50% HF) and the larger flat heads.;The BF of these tablets increased with increasing HF diameter. For formulations compressed using `D' tooling this trend was observed only up to a CF of 15KN, beyond which the BF decreased. This observation could be attributed to work-hardening of the formulation at higher CF. These formulations also exhibited capping at CF above 15KN and with higher HF diameters. The capping index was found to increase with increasing HF diameter. |
