Mean Yield Pressure (Py) and Strain Rate Sensitivity (SRS) of Polyols

Pharmaceutically applicable polyols are represented by different chemical compounds with different structures by different commercial grades with different mechanical properties. The mean yield pressure (Py) reflects the required pressure for irreversible deformation of the material. While the strain rate sensitivity (SRS) reflects the effect of deformation speed on the mentioned Py. Thise characteristics of materials (Py and SRS) are very important for manufacturing of tablets and process scale-up.
Method. Unlubricated powder samples of polyols were tableted with compaction simulator STYL’One Nano (Medelpharm, Beynost, France) using with round flat Euro B punches (D=7 mm) to obtain tablets with a target mass around 200 mg. The powder feeding into the die was performed automatically via the feed shoe. The die and punches were lubricated manually with sodium stearyl fumarate (PRUV®; JRS Pharma, Rosenberg, Germany) using a brush before every tableting cycle. Tableting cycles simulated single-punch eccentric tablet press were performed at axial punch speeds of 1 and 90 mm/s (“slow” and “fast”, respectively). A ‘V-shape’ (‘saw-tooth profile’) profile in accordance with the USP Pharmacopeia monograph <1062> with linear compression and decompression phases was used. In-die Py was determined automatically using the linear part of the ascending curve in the pressure range of approx. 100-350 MPa (Alix software ver. 20220711; Medelpharm, France). For every commercial grade of polyol, based on the preparation of ten tablets, ten single values of Py was automatically determined and average value (Av.) and standard deviations (S.D.) were calculated. Based on the Av. Py at punch speeds of 1 mm/s and Av. Py at punch speeds of 90 mm/s, the SRS (%) was calculated.
Data. Individual measurements of Py (and additionally Av. and S.D.) and calculated SRS values were presented in the form of a CSV spreadsheet (Py data & SRS.csv). To simplify the reusing of data, for every studied polyol grade, SRS was plotted versus Py at punch speeds of 1 mm/s (Py slow). The respective table of data as a CSV spreadsheet (SRS vs. Py slow.csv) and visualization (Figure.jpg) were added.