## Materials and Methods
### Methods
#### Powder Characterization  
Bulk Density Measurement  
An appropriate amount of powder samples of the raw (un-compacted) and roller compacted (1 st, 2 nd, and 3 rd cycles) Avicel PH-101 was carefully poured, in triplicate, into a 100 mL graduated cylinder. The volume was then read directly from the cylinder and used to calculate the bulk density according to the relationship: mass/volume. True Density Measurement  
The true density of the powders (un-compacted and compacted Avicel PH-101) was determined by placing approximately one gram of the powder sample in a small sample cell in a helium gas pycnometer followed by pressurizing the system between 15 and 17 psi with helium. The true density was then calculated by dividing the mass of the material by its volume (the mean of five readings for each sample was obtained). All weight measurements were performed using an analytical balance with a resolution of \(\pm\) 0.1 mg. Particle size distribution was established based on the ASTM (American Society for Testing and Materials) sieve analysis method, using a sieve shaker equipped with a series of eight sieves of 63, 90, 125, 180, 250, 425, 500, and 600 um openings. Fifty-gram samples of un-compacted and compacted Avicel PH-101 powder were tested with an amplitude setting of 1.5 mm and 5 min total sifting time. Powder particles from each sieve were collected and weighed using an electronic balance. Cumulative curves were constructed based on the weight percent of remaining powder particles in the sieves versus mean diameter of powder particles. Porosity of Powders  
Total pore volume, total pore surface area, and total and median pore sizes of powders representing un-compacted and compacted (1 st, 2 nd, and 3 rd cycles) Avicel PH-101 were determined using a mercury porosimeter (PoreMaster PM-60-13, Quantachrome, Boynton Beach, FL, USA). A representative sample of 0.1 g was accurately weighed and placed in a calibrated glass cell, which was installed in a low-pressure mercury chamber for measurement of particles in the size range of 4-200 um. Gas was evacuated from the sample cell, and mercury was then transferred into the sample cell; the intrusion pressure was increased and the corresponding volume of mercury injected into the cells was recorded. The range of pressure applied to force mercury into the sample cell was 1-50 Pa. As a result of the analyses, intrusion curves and parameters describing the pore structure of the samples were obtained. Scanning Electron Microscopy Analysis  
Powder samples of the raw (un-compacted) and roller compacted (1 st, 2 nd, and 3 rd cycles) Avicel PH-101 were analyzed using Scanning Electron Microscopy, SEM (Inspect F50, FEI, Eindhoven, Netherlands). The powder samples were fixed on aluminum stubs and then coated with gold in a low-vacuum sputter coating chamber (Emitech K550X, Quorum Technology England, Lewes, UK) using a beam current of 20 mA/dm\({}^{3}\) for 105 s.  
X-ray Powder Diffraction (XRPD)  
Raw (un-compacted) Avicel(r) PH-101, Avicel(r) PH-101 subjected to 1 st, 2 nd, and 3 rd compaction cycles were tested using an X-ray powder diffractometer (Bruker, Karlsruhe, Germany) in 20 reflection mode and a range of 2-40\({}^{\circ}\). The X-ray compartment used consisted of a D2 Phaser in a ceramic sealed X-ray tube with Cr, Co, Cu radiation operating at 30 kV/10 mA. DIFFRAC_SUITE(tm) computer software was used to measure and analyze the data. The XRPD spectra of the compacted and non-compacted Avicel PH-101 powders were compared with ball milled Avicel PH-101 as a reference. It is evident that the ball milled Avicel PH-101 yielded a clear amorphous pattern (Figure 1). The relative amount of crystallinity in cellulose samples was estimated using a method described by [PERSON] and coworkers [PERSON] and coworkers [PERSON] (1996) to calculate the crystallinity index (CrI).