Tablets types

To demonstrate the ability to evaluate intersample variations, an over-the-counter (OTC) pain relief medication from two different manufacturers was compared. The samples contain three APIs each acetaminophen, aspirin and caffeine. Pure acetaminophen, aspirin and caffeine samples are obtained in either tablet form or powder compact and included within the same FOV as the tablets to provide simultaneous reference materials for the tablet samples. The tablets and pure components were arranged as shown in Plate 8.1a. Measurements on all samples were collected simultaneously. Tablet A samples from one manufacturer have a reported label concentration of 37%, 37%, and 10%, for the three API components, respectively. Tablet B samples from the second manufacturer contain the same three APIs, at label concentrations of 39%, 39%, and 10 %, respectively. In addition to these samples, tablet C samples are included in the array of tablets. These samples contain only acetaminophen as the API with a reported label concentration of 79%, and are made by the manufacturer who produces tablet A. The remaining mass of all three tablet types represents the excipient (binder, disintegrant, and lubricant) materials. 

A powder compact s TS is the stress required to separate its constituent particles in tensile mode. This is measured for the tableting indices by transverse compression of the square compacts, using narrow platens. Stresses build within the sample until it fails in a tensile mode that is perpendicular to the direction of platen movement. Tablets that are manufactured on a traditional tablet press and that have high TS are considered hard and generally robust, and so this is a highly desired attribute for immediate release and other tablet types. 

Figure 2.7 The figure shows the layout of a tablet matrix comprised of tablet types A, B and C, in addition to pure components acetaminophen, aspirin and caffeine. Each tablet is 10 mm in diameter, and the overall sample and pure component matrix covers an area 9x7 cm2.

Guidance on compression levels for each tablet type (series 1,2, and 3) and maximum punch pressures are given in Table 1 ... 

Scrape-off height For many tablet types (e.g., deep concave tablets) the height of the lower punch at the point of scrape-off must be increased to ensure that the tablet is removed completely from the die when it impacts the tablet stripper. 

Formulation as tablets gives similar advantages and disadvantages to those associated with water-soluble bags. Many tablets include the use of an effervescent agent that ensures the rapid dispersion of the formulation. Care is needed when using water-soluble packaging and tablet-type formulations as part of a tank mix, since other components could impede dispersion of the formulation. Under such circumstances, tablets and water-soluble packs should be loaded into the sprayer ahead of other components. 

Bioavailability, Bioequivalence, and Pharmacokinetics. Bioavailabihty can be defined as the amount and rate of absorption of a dmg into the body from an adrninistered dmg product. It is affected by the excipient ingredients in the product, the manufacturing technologies employed, and physical and chemical properties of the dmg itself, eg, particle size and polymorphic form. Two dmg products of the same type, eg, compressed tablets, that contain the same amount of the same dmg are pharmaceutical equivalents, but may have different degrees of bioavailabihty. These are chemical equivalents but are not necessarily bioequivalents. For two pharmaceutically equivalent dmg products to be bioequivalent, they must achieve the same plasma concentration in the same amount of time, ie, have equivalent bioavadabihties. 

Compressed Tablets. This popular type of dosage form offers convenience, stabiUty, accuracy and precision, and good bioavadabihty of active ingredients. After the best formulation has been estabflshed, compressed tablets can be manufactured at high rates of speed on advanced equipment. Tablets can be made to achieve rapid dmg release or to produce delayed, repeat, or prolonged therapeutic action (Controlled release technology, pharmaceutical). ... 

Tablet Press. The main components of a tablet compression machine (press) are the dies, which hold a measured volume of material to be compressed (granulation), the upper punches which exert pressure on the down stroke, and the lower punches which move upward after compaction to eject the tablets from the dies. Mechanical components deflver the necessary pressure. The granulation is fed from a hopper with a feed-frame on rotary-type presses and a feeding shoe on single-punch presses. A smooth and even flow ensures good weight and compression uniformity. Using the proper formulation, demixing in the hopper is minimized.

Formulation. Compressed tablet formulations contain several types of inert, adjuvant ingredients necessary for proper preparation and therapeutic performance. Tablets designed to be swallowed need diluent, disintegrating, binding (adhesive), and lubricating inert ingredients, whereas... 

Uses. Aspirin has analgesic, antiinflammatory, and antipyretic activity. It is used for the reHef of less severe types of pain, such as headache, neuritis, acute and chronic rheumatoid arthritis, and toothache. Aspirin can be purchased in a variety of OTC and prescription dosage forms made and formulated by many companies. Tablets, ie, buffered, plain, or enteric-coated, are the most familiar in the United States, but other forms such as powder and effervescent formulations are of considerable importance in other parts of the world. 

When the bulk containing the binder is uniform, it is compressed on pneumatic, hydraulic, or ram-type presses. Compression can be carried out in presses provided with suitably designed cavities or in metallic pans. The pans ate filled with the powder mass, and a plunger with a cross-sectional shape similar to that of the pan is used to compress the tablet. The resulting tablets ate commonly used with powder puffs or cosmetic bmshes. 

The advantages of this type of system are that the release rates are independent of the dmg properties, macromolecules and ionic species may be dehvered, fluxes may be high, and release rates are not dependent upon environmental conditions such as pH. The disadvantages are that the system is subject to dose-dumping if it is chewed. It is also more expensive to formulate than coating tablets, and there is a possibiUty of hole plugging. 

Binders improve the strength of compacts through increased plastic deformation or chemical bonding. They may be classified as matrix type, film type, and chemical. Komarek [Chem. Eng., 74(25), 154 (1967)] provides a classification of binders and lubricants used in the tableting of various materials. 

Roll presses can produce large quantities of materials at low cost, but the product is fess uniform than that from molding or tableting presses. The introduction of the proper quantity of material into each of the rapidly rotating pockets in the rolls is the most difficult problem in the briquetting operation. Various types of feeders have helped to overcome much of this difficulty. 

Switch on and allow the instrument to warm up the time for this will be quite short if the circuit is of the solid-state type. While this is taking place, make certain that the requisite buffer solutions for calibration of the meter are available, and if necessary prepare any required solutions this is most conveniently done by dissolving an appropriate buffer tablet (these are obtainable from many suppliers of pH meters and from laboratory supply houses) in the specified volume of distilled water. 

Absorbance Reading [AU] Tablet Weight [mg] Assay [mg] Calibration Factor Type of Result... 

Solid catalysts can be subdivided further according to the reactor chosen. Dependent on the type of reactor the optimal dimensions and shapes of the catalyst particles differ. Catalysts applied in fixed beds are relatively large particles (typically several mm in diameter) in order to avoid excessive pressure drops. Extrudates, tablets, and rings are the common shapes. Figure 3.9 shows some commonly encountered particle shapes. 

---