Tablet properties friability

When evaluating the effect of binder concentration on a number of tablet properties, surface area measurements were used to investigate the bond strength of the binder with the other particles [18]. A steady reduction in the surface area of the granules with increasing binder concentration indicated that the binder had covered or penetrated the particles, with the formation of particle-binder bonds. This was related to friability, and the increased bond strength was related to the decreased surface areas. 

Many papers have been published in which an experimental design is used to optimize tablet formulations. Both process variables as well as compositional variables (quantitative and qualitative) were used as independent (adjustable) variables. The studied dependent variables (factors to be optimized) are physical tablet properties directly after preparation such as weight variation, crushing strength, dissolution profile, disintegration time and friability. Doombos reviewed papers in which statistical methods were used to optimize tablet formulations [13]. 

The compaction process can be described by a variety of force (or pressure)-displacement profiles, such as force versus time, force versus tablet porosity, and force versus tablet properties (hardness, friability, dissolution, etc.). The effect of compaction speed on a variety of tablet properties can also be studied. 

General instructions for the determination of tablet properties (e.g., hardness, disintegration, friability, dissolution profile, and stability) are contained in pharmacopeia [e.g., European Pharmacopoeia (Eur. Ph.) and U.S. Pharmacopeia (USP)]. 

Table 176 shows how it was possible to considerably improve the tabletting properties of an antiacid tablet containing alginic acid, magnesium trisilicate, aluminium hydroxide and sodium hydrogen carbonate as the active principles by the addition of copovidone. The hardness was doubled and the friability reduced by half. 

Today, both MCC and PC fiber grades are widely used in tabletting. Depending on the composition of the formulation, one or the other cellulose product results in better hardness, friability, and disintegration values. However, the quantity of MCC required to yield comparable tablet properties is normally at least one-third higher than that of PC fibers. Since, because of a more economical production process, the cost of PC fibers is also lower than that of MCC, monetary advantages can be derived from using powdered cellulose. 

The studies described in this chapter are restricted to the physical stability of tablets. Physical properties that are of interest are e.g. crushing strength, friability, disintegration time and dissolution profile. One of the causes of... 

Compacts were milled and final blends were compressed into tablets (Table 8 gives resultant powder properties). Tablets were tested for friability, thickness, hardness, and drug release. 

Tablet SF, TS (in MPa), CS or pressure (in MPa), and friability were calculated from the tablet measurements, the compression forces, and the tooling dimensions. Plots of SF versus TS and TS versus CS were generated curves were fitted to the data and the properties at 0.85 SF and at the apex of the TS versus CS profile were determined.

The general instructions for the determination of the corresponding properties of tablets (hardness, disintegration, friability, dissolution) are contained the Pharmacopoeiae Ph.Eur. or USP. If it is not stated to the contrary, the disintegration time is measured in artificial gastric juice. The release is determined by the conditions laid down in the corresponding monographs for the tablets (usually USP) and in the prescribed medium. 

Given the fact that only a very low amount of dmg is incorporated, its physical and mechanical properties typically do not alter the formulation characteristics and do not influence the downstream manufacturability to a large extent. While it is known for high dmg load formulations that compressibility and tablet attributes such as hardness, friability, and disintegration are in some cases strongly dependant on the characteristics of the API, this is not true for low-dose formulations. The latter formulations... 

Physical properties test equipment Any physical properties testing that has the possibility of generating a dust or aerosol must be contained in the isolator. This type of equipment (e.g., tap density, friability, tablet hardness test equipment) should then be placed directly inside an isolator. 

In the manufacture of tablets it is important to define and appreciate the physical properties of the active substance, in particular particle size and flowability. The technology involved in direct compression assumes great importance in tablet formulations because it is often the least expensive, particularly in the production of generics that the active substance permits. The limiting factors are the physical properties of the active substance and its concentration in the tablets. Even substances such as ascorbic acid, which are not generally suitable for direct compression owing to the friability of the crystals, can normally be directly pressed into tablets at concentrations of 30-40%. Ffowever, this technique is not as suitable if the content of ascorbic acid is higher. This limit may be shifted upward by special direct-compression auxiliaries, for example, Ludipress (BASF). 

Sustained-release matrix tablets with good properties were obtained with a dextran-HPMC ratio of 4 1 (w/w), with a matrix excipient-PPL ratio of 60 40 (w/w), and with a cetyl alcohol amount of 15% (w/w).The hydrophilic polymers-PPL ratio of 60 40 (w/w) is more robust for any manufactured variability than 50 50 (w/w), because the central point of the design is near the lowest desired area (Figure 22). Under the optimal conditions, the mean value of hardness was 106 3 N and the friability was less than 1% (0.2%). 

In the batch represented in Fig. 6, a novice operator trainee has stopped the batch well before the peak of the derivative. This required a major adjustment of the tableting operation (force and speed) to produce tablets in an acceptable range of material properties (hardness and friability). 

However, it has been possible to demonstrate in the production of caffeine tablets, that povidone K 25 increases the particle size and bulk density of the granulate, giving it better flow properties and reducing the friability of the tablets [400]. 

The objective was to obtain tablets of low friability and satisfactory hardness. Good compression properties were also needed, that is a high transmission ratio and also a high cohesion index (see below). A granulate with at least 20% fine particles was also considered desirable, for the powder to flow correctly. 

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