Effect of repeated compaction of tablets on tablet properties and work of compaction using an instrumented laboratory tablet press (original) (raw)
Related papers
2011
Purpose: To comparatively evaluate the tableting properties of binary mixtures and bilayer tablets containing plastic deformation and brittle fracture excipients. Methods: Binary mixture and bilayer tablets of microcrystalline cellulose (MCC), ethyl cellulose, anhydrous lactose and dextrate were prepared by direct compression and the effect of compaction pressure on the materials was investigated by scanning electron microscopy (SEM). True, bulk and tap densities of excipients were determined. Furthermore, Heckel equation and Carr’s index were used to analyze the compression behaviour of the tablets. Results: The flowability of dextrate, based on Heckel and Carr’s Index data, was superior to that of other powder excipients tested. No significant difference was observed between the tensile strength of binary and bilayer tablets of the same composition. However, the tensile strength of binary and bilayer tablets of different compositions varied significantly (p < 0.001), e.g., the ...
EPJ Web of Conferences, 2017
In the pharmaceutical field, tablets are the most common dosage form for oral administration in the world. Among different manufacturing processes, direct compression is widely used because of its economics interest and it is a process which avoids the steps of wet granulation and drying processes. Tablets are composed of at least two ingredients: an active pharmaceutical ingredient (API) which is mixed with a diluent. The nature of the powders and the processing conditions are crucial for the properties of the blend and, consequently, strongly influence the mechanical characteristics of tablets. Moreover, tablets have to present a suitable mechanical strength to avoid crumbling or breaking when handling, while ensuring an appropriate disintegration after administration. Accordingly, this mechanical property is an essential parameter to consider. Experimental results showed that proportion of the diluent, fragmentary (DCPA) or plastic (MCC), had a large influence on the tensile strength evolution with API content as well as the compression load applied during tableting process. From these results a model was developed in order to predict the tensile strength of binary tablets by knowing the compression pressure. The validity of this model was demonstrated for the two studied systems and a comparison was made with two existing models.
Purpose: To comparatively evaluate the tableting properties of binary mixtures and bi-layer tablets containing plastic deformation and brittle fracture excipients. Methods: Binary mixture and bi-layer tablets of microcrystalline cellulose (MCC), ethyl cellulose, anhydrous lactose and dextrate were prepared by direct compression and the effect of compaction pressure on the materials was investigated by scanning electron microscopy (SEM). True, bulk and tap densities of excipients were determined. Furthermore, Heckel equation and Carr’s index were used to analyze the compression behavior of the tablets. Results: The flowability of dextrate, based on Heckel and Carr’s Index data, was superior to that of other powder excipients tested. No significant difference was observed between the tensile strength of binary and bi-layer tablets of the same composition. However, the tensile strength of binary and bi-layer tablets of different compositions varied significantly (p < 0.001), e.g., the tensile strength of microcrystalline cellulose (MCC)/ethyl cellulose (EC) tablets (50/50) was 1.77 MPa while that of MCC/dextrate at 50/50 composition was 1.47 MPa. Conclusion: Binary mixture and bi-layer tablets show similar behavior when formulated using excipients of similar deformation properties. However, their behavior changes when excipients with different deformation properties are blended together. Keywords: Binary mixture, Bi-layer tablet, Brittle fracture, Plastic deformation, Tensile strength.
Mechanical properties of powders for compaction and tableting: an overview
Pharmaceutical Science & Technology Today, 1999
This review provides an insight into mechanical properties that are critical to understanding powder processing for tableting. Various parameters that reflect these basic fundamental properties of powder and their evaluation by different techniques are described. Some recent examples in which these techniques are used in drug substance selection, formulation optimization or scale-up are also provided.
COMPRESSION PHYSICS OF PHARMACEUTICAL POWDERS: A REVIEW
Due to various advantages such as high-precision dosing, manufacturing efficiency and patient compliance helped making tablets the most popular dosage forms among all available dosages forms. Compaction, which is an essential manufacturing step in the manufacture of tablets, mainly includes compression (i.e. reduction of volume of the powder under consideration and particle rearrangement) and consolidation (i.e., formation of interparticulate bond to facilitate stable compaction). The success of the compaction process depends not only on the physico-technical properties of drugs and excipients, but also on the instrument settings with respect to rate and magnitude of force transfer. Tablet manufacturing speed and pre/main compression force profile also have an influence on the quality of the final tablet. Mechanical aspects of tablet formation can be studied using, instrumented punches/dies, instrumented tablet punching machines, and compaction simulators. These have potential application in pharmaceutical research and development, such as studying basic compaction mechanism, various process variables, scale-up parameters, trouble shooting problems, creating compaction data library, and fingerprinting of new active pharmaceutical ingredients (APIs) or excipients. Mathematical models, forcetime, force-distance, and die-wall force parameters of tablet manufacturing are used to describe work of compaction, elasticity/plasticity, and time dependent deformation behavior of pharmaceuticals powder under consideration.
Effect of Compression Force on Tablet Hardness and Disintegration Time
By using three different compression forces, tablets have been produced from selected Ascorbic Acid granules. The hardness and disintegration time of the tablets has been studied by using standard methods. Thus, the effect of compression forces on tablet hardness and disintegration time has been investigated. The result points out that the compression pressure has an intense effect on the tablet hardness and disintegration time. Tablet hardness increases with increasing compression pressure. The same statement is also applicable to the tablet disintegration time, i.e. the disintegration time increases with increasing compression pressure. However, the compression force is supposed to have a much greater effect on the disintegration time than on the hardness.
Compression Physics in the Formulation Development of Tablets
The advantages of high-precision dosing, manufacturing efficiency , and patient compliance make tablets the most popular dosage forms. Compaction, an essential manufacturing step in the manufacture of tablets, includes compression (i.e., volume reduction and particle rearrangement), and consolidation (i.e., interparticulate bond formation). The success of the compaction process depends not only on the physico-technical properties of drugs and ex-cipients, especially their deformation behavior, but also on the choice of instrument settings with respect to rate and magnitude of force transfer. This review discusses various properties of drugs and excipients, such as moisture content, particle size and distribution, polymorphism, amorphism, crystal habit, hydration state, and lubricant and binder level of the blend that have an influence on compaction. Tableting speed and pre/main compression force profile, also have a bearing on the quality of the final tablet. Mechanistic aspects of ta-bleting can be studied using, instrumented punches/dies, instrumented tablet-ing machines, and compaction simulators. These have potential application in pharmaceutical research and development, such as studying basic compaction mechanism, process variables, scale-up parameters, trouble shooting problem batches, creating compaction data bank, and fingerprinting of new active pharmaceutical ingredients (APIs) or excipients. Also, the mathematical equations used to describe compaction events have been covered. These equations describe density–pressure relationships that predict the pressures required for achieving an optimum density. This understanding has found active application in solving the analytical problems related to tableting such as capping, lamination , picking, sticking, etc. Mathematical models, force-time, force-distance, and die-wall force parameters of tableting are used to describe work of compaction, elasticity/plasticity, and time dependent deformation behavior of pharmaceuticals. Various indices of tableting performance such as the bonding index, brittle fracture index, and strain index can be used to predict compaction related problems. Compaction related physico-technical properties of commonly used ta-bleting excipients have been reviewed with emphasis on selecting suitable combination to minimize tableting problems. Specialized tools such as co-processing of API and excipients can be used to improve their functionality.
Tensile strength of tablets containing two materials with a different compaction behaviour
International journal of pharmaceutics, 2000
The tensile strength of tablets compressed from binary mixtures is in general not linearly related to the strength of tablets prepared from single materials; in many cases it shows a decreased tensile strength relative to interpolation. The materials used in this study, sodium chloride and pregelatinised starch, are both plastically deforming materials, but have a different densification and relaxation behaviour. The yield pressure of the binary mixtures shows an almost linear relationship. As an effect of their lower yield pressure, starch particles yield earlier than sodium chloride particles. The following enclosure prevents some sodium chloride particles to yield or crack. The relaxation of the tablets is higher than the relaxation calculated by linear interpolation of the relaxation behaviour of the two pure materials. The difference between the measured porosity expansion and the data obtained by linear interpolation can be considered as a measure for the reduced interparticle...
Powder Technology, 2006
The purpose of this work consists in following the dependence of physical properties on the temperature during the compaction of an organic component. A special thermo-regulated die has been developed to realize uniaxial compression at different constant temperatures. This study has shown that a temperature change modifies the microstructures and the mechanical behaviour of the tablets. The measurement of the tablet porosity during the compression cycle allows us to conclude that temperature influences mainly the phenomena occurring during the isobaric stage of the compression cycle and not the ones during the pressure increase. On the other hand, during the pressure increase, the acoustical activity of the powder is reduced when temperature increases. The tensile strength of tablets realized at different temperatures was also studied and shows a maximum around 60 °C that can be explained by the SEM analysis of the microstructure of the tablets.
Particulate Science and Technology, 2003
The axial and radial powder movements during the compaction process were investigated using flat-and curved-face punches for the case of single-ended axial strain applications. The density distributions in microcrystalline cellulose tablets were determined experimentally using a colored layer technique and digital image analysis. Nondestructive topography measurements were taken to assess the variation in surface roughness of the tablets and relate this to the forming pressure and density distribution. Results showed that the tablets produced were highly nonhomogeneous with high density regions in the ''top corners'' (adjacent to the moving punch surface) and ''middle bottom half'' for the flat-face tablets. For instance, at 92.7 MPa, density values were recorded at greater than 1.2 g=cc in the high density regions and greater than 0.6 g=cc in low density regions with regards to experimental results. High density regions were noted in the corners where the powder was in contact with the die wall for the curved-face tablets; both axial and radial powder movement was seen to be taking place. Surface topography and surface form results also showed that the geometric location of the corresponding surfaces of the tablets were relocated after the compaction process due to elastic recoil and stress relief.