Category: Formulation and Quality
Purpose: The goal of this work was to investigate the influence of different HPMC grades, lubricants, and binders on mini tablet physical properties. More specifically tablet hardness, thickness, and weight were examined as a function of the formulation components chosen. Three different grades of HPMC were explored, two types of binders: microcrystalline cellulose and silicified microcrystalline cellulose, and two types of lubricant: magnesium stearate and sodium stearyl fumarate. Additionally, tableting speed and compression force were modulated to understand the effect that processing parameters have on resulting tablet physical properties.
Methods: Mini-tablets were made using a 16-station Manesty Beta Press, equipped with tooling containing four 2-mm round concave dies per tooling set. All components except the lubricant were blended for 10 minutes in a V-blender. Lubricant was then added to the resulting blend, and the mixture was blended for an additional 1 minute. Tablet dies were left in the fully open position to keep tablet weights the same and investigate the ability of each formulation to fill the die cavity. The press was operated at turret speeds of 20, 40, 50, and 60 rpm; and tablets were compressed at 700 and 1000 lbs of force. Prior to physical testing, tablets were allowed to equilibrate for 24 hours following compaction. From the resulting tablets, 25 from each formulation or set of trial conditions were tested for tablet strength using a Key International HT-300 hardness tester, weights were measured using an analytical balance, and thicknesses were measured by hand using a caliper. Data was collected and then analyzed using JMP Pro 14.2.0 statistical analysis software.
Results: Mini-tablet physical properties were affected by incorporating different formulation components. Figure 1 shows the difference in overall tablet hardness as a function of the lubricant choice. Tablets made with sodium stearyl fumarate showed higher tablet strengths than tablets made with magnesium stearate. Magnesium stearate has a tendency to over-lubricate and coat polymer particles which can result in lower tablet hardness, whereas sodium stearyl fumarate does not tend to over-lubricate as easily. The tablet weights did not change based on which lubricant was chosen, as shown in Figure 2. When higher strength mini-tablets are desired, sodium stearyl fumarate can be used as the lubricant without affecting the desired tablet weight. The impact of the HPMC grade and the binder type will be further communicated in the poster.
Conclusion: Mini-tablet physical properties can be manipulated by formulation component choices. Using sodium stearyl fumarate as the lubricant provides harder tablets, independent of polymer grade selected. Lubricant type does not have an impact on weight variability, so it does not affect the flow properties of the formulation.