Application of lower Punch Vibration to improve the mechanical Stability of Tablets

A sufficient mechanical stability of tablets to be compacted prevents problems during tableting (e.g. sticking, capping, lamination) and is crucial with regard to further processing steps such as coating or packaging. Often, an improvement of the mechanical stability is only achievable by an adaption of the production settings (die disk speed) or an alteration of the powder blend composition. In the present study, a novel lower punch vibration device was developed and implemented on a rotary tablet press to improve the mechanical stability of the resulting tablets without changing the production conditions or the powder formulation. Various types of microcrystalline cellulose with different physical properties were selected. The powders were investigated concerning their powder flow, density, particle morphology and surface area and the tablets concerning their weight, tensile strength, and capping index. The results showed that externally applied lower punch vibration improved the mechanical stability of the investigated tablets beyond the adaption of the production settingss and the physical properties of the powder blend

Evaluation of the suitability of various lubricants for direct compaction of sorbitol tablet formulations

There is an increasing interest in polyols such as sorbitol in pharmaceutical tablet formulations due to their sweet taste but reduced calorie content and noncariogenic characteristics. Sorbitol is a common tableting excipient and plays a major role in the manufacture of chewable and sublingual tablets. One limitation of sorbitol as tableting excipient is that its hygroscopic nature may cause pronounced friction as well as sticking to the punch surfaces. Therefore, the aim of the present study was to evaluate the suitability of various lubricants for reduction of friction and prevention of sticking during compaction of sorbitol-containing tablets. The efficiency of the most commonly used lubricant magnesium stearate was compared to that of sodium stearyl fumarate (Pruv®), microprilled poloxamer 407 (Lutrol® micro 127) and PEG 4000. Compaction studies were performed using an eccentric tablet press as well as a rotary die tablet press. In addition to the compaction properties, the effect of the investigated lubricants on the tablet properties was evaluated. Considering both the lubricant efficiency and the influence on tablet properties among the investigated lubricants, Pruv® turned out to be most suitable for compaction of the investigated sorbitol tablet formulations. However, the best overall lubricant performance accompanied by excellent tablet properties was observed with a mixture (1:1) of magnesium stearate and Pruv®, indicating a synergistic effect of both lubricants

Evaluation of the suitability of various lubricants for direct compaction of sorbitol tablet formulations

There is an increasing interest in using polyols, such as sorbitol, in pharmaceutical tablet formulations due to their sweet taste and reduced calorie content and noncariogenic characteristics. Sorbitol is a common tableting excipient and plays a major role in the manufacture of chewable and sublingual tablets. One limitation of sorbitol as a tableting excipient is that its hygroscopic nature may cause pronounced friction, as well as, sticking to the punch surfaces. Therefore, the aim of the present study was to evaluate the suitability of various lubricants for reducing friction and preventing sticking during the compaction of sorbitol-containing tablets. The efficiency of the most commonly used lubricant, magnesium stearate, was compared to that of sodium stearyl fumarate (Pruv®), microprilled poloxamer 407 (Lutrol® micro 127) and PEG 4000. Compaction studies were performed using both an eccentric tablet press and a rotary tablet press. In addition to their compaction properties, the effect of the investigated lubricants on the tablet properties was evaluated. Considering both the lubricant efficiency and the influence on tablet properties of the investigated lubricants, Pruv® was found to be most suitable for compaction of the investigated sorbitol tablet formulations. However, the best overall lubricant performance, accompanied by excellent tablet properties, was observed with a mixture (1:1) of magnesium stearate and Pruv®, indicating synergism between these lubricants

Influence of Base Oil Polarity on the Transient Shear Flow of Biodegradable Lubricating Greases

The scope of this study is to elucidate the physical mechanisms influencing the transient flow behavior of lubricating greases based on biogenic oleochemicals from a polarity point of view. This includes the mutually interacting influence of base oil polarity and thickening agents on the rheologically-measured mechanical structural degradation in transient shear flow. Due to the high temperature dependence of Keesom forces in the background of polar-active bond mechanisms, the analysis of the transient flow response as a function of temperature allows to attribute the observed influences to differences in base oil polarity. In general, clay-thickened greases show a greater tendency to be rheologically influenced by base oil polarities than soap-thickened lubricating greases

A non-destructive method for quality control of the pellet distribution within a MUPS tablet by terahertz pulsed imaging

Terahertz pulsed imaging (TPI) was applied to analyse the inner structure of multiple unit pellet system (MUPS) tablets. MUPS tablets containing different amounts of theophylline pellets coated with Eudragit® NE 30 D and with microcrystalline cellulose (MCC) as cushioning agent were analysed. The tablets were imaged by TPI and the results were compared to X-ray microtomography. The terahertz pulse beam propagates through the tablets and is back-reflected at the interface between the MCC matrix and the coated pellets within the tablet causing a peak in the terahertz waveform. Cross-section images of the tablets were extracted at different depths and parallel to the tablet faces from 3D terahertz data to visualise the surface-near structure of the MUPS tablets. The images of the surface-near structure of the MUPS tablets were compared to X-ray microtomography images at the same depths. The surface-near structure could be clearly resolved by TPI at depths between 24 and 152 μm below the tablet surface. An increasing amount of pellets within the MUPS tablets appears to slightly decrease the detectability of the pellets within the tablets by TPI. TPI was shown to be a non-destructive method for the detection of pellets within the tablets and could resolve structures thicker than 30 μm. In conclusion, a proof-of-concept was provided for TPI as a method of quality control for MUPS tablets