Issue link: https://www.e-digitaleditions.com/i/678483
Tablets & Capsules May 2016 33 itself. Using the powder compaction analyzer, we have taken real-time measurements of both the punch position and the punch force. That enables us to analyze continu- ous force-displacement data to understand the dynamics of compaction in real time. This analysis includes a dynamic profile of both yield stress (a measure of plastic- ity) and Young's modulus (a measure of elasticity) of the powder bed during compaction. Figure 9 illustrates dynamic compaction profiles for three different tablet weights of Avicel PH102 microcrystalline cellulose (FMC, Philadelphia, PA). Yield stress is tablet-size dependent and the yield stress profiles shown here confirm that. What's more notable is that the elasticity profiles are independent of tablet size. We're evaluating this new work to understand the signifi- cance of this novel in-die dynamic compaction analysis and to identify how the information can be directly applied to improve formulation development. Future applications Dynamic powder compaction analysis can play a key role in developing tablet formulations. To get the most benefit, we should routinely characterize the compaction behavior of individual excipients, APIs, and formulations very early in development. By so doing, we can apply the data to new mechanisms of feedback and/or feedforward control systems that determine whether batches meet minimum standards. Better yet, these control systems could ensure the optimal combination and concentration of excipients and API in our blends. Dynamic in-die compaction measurements may also help us understand the complexity of tablet formulations. It's even conceivable that an at-line benchtop tablet exam will be able to use an historical database of material-specific compaction data to simplify in-process decisions using a single-point compaction measurement. T&C References 1. Amidon, Gregory E; Akseli, Ilgaz; Goldfarb, David; He, Xiaorong; Sun, Changquan C Proposed New USP General Information Chapter "Tablet Compression Characterization <1062>," Pharmacopeial Forum 40(4), 2014. 2. Tye, CK; Sun, CC; and Amidon, GE. Evaluation of the effects of tableting speed on the relationships between compaction pressure, tablet tensile strength, and tablet solid fraction. J Pharm Sci 94(3): 465-472, 2005. 3. Gamlen, M. Tabletability assessment: Good form. Innovations in Pharmaceutical Technology. Issue 49: 58- 61, June 2014. 4. Fell, JR and Newton, JM. The tensile strength of lactose tablets. J Pharm Pharmacol 20(8): 657-659. 1968. 5. Newton, JM; Rowley, G; Fell, JT; Peacock, DG; and Ridgway, K. Computer analysis of the relation between tablet strength and compaction pressure. J Pharm Pharmac 23: 195S-201S, 1971. Joe Domingue is president of SciMark International, 24726 Kings Road, Laguna Niguel, CA 92677. Tel. 949 495 1897. E-mail: joe.domingue@gmail.com. SciMark is the North Amer- ican representative of Gamlen Tableting. Michael Gamlen, PhD, is managing director of Gamlen Tableting, Biocity Not- tingham, Nottingham NG1 1GF United Kingdom. Tel. +44 115 912 4271. Website: www.gamlentableting.com. He has more than 30 years' experience in tablet development and led tablet development at The Wellcome Foundation for 15 years. He specializes in managing product development, formulation, and tablet and process development studies. Figure 9 Three-dimensional dynamic compaction profiles of elasticity and plasticity 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 MPa Tablet weight - 50% 37 mg, 100% 75% & 150% 112 mg 50 100 150 0 20 40 60 80 100 120 140 160 180 200 0 20 40 60 80 100 120 140 160 180 200 a. Elasticity versus compression pressure for microcrystalline cellulose at three tablet weights b. Plasticty versus compression pressure for microcrystalline cellulose at three tablet weights Compression pressure (MPa) 120 100 80 60 40 20 0 MPa Tablet weight - 50% 37 mg, 100% 75% & 150% 112 mg 50 100 150 Compression pressure (MPa)