Compressed tablets

With ground sugar being the principal material, all other ingredients must be granulated first. Granulation of dextrose and sorbitol is not needed. 

The dried mixture is ground to a standard grain size of 2-3 mm which then is fed again into a powder mixer. Separating agents and flavourings are added to the mixture. 

Effervescent tablets are a special group in this category. Processing is identical to compressed tablets except for the addition of sodium carbonate during and citric acid after granulation. 

Sorbitol is the principal ingredient of sugar-free compressed tablets. To enhance the sweet taste usually artificial sweeteners (aspartame, cyclamate, saccharin) are used. 

Flavourings used in compressed tablets are mainly encapsulated powder flavourings. Taste directions are mainly mint and citms. They either have to be stabilized against oxidation or they have to be compounded without ingredients liable to oxidize or these ingredients have to be removed (e.g. terpenes). 

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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). ... 

Compressed tablets that are composed of several layers require specially adapted presses designed with several fed hoppers. For a two-layer tablet, one granulation is first fed to a die and partially compressed into a soft tablet. The second granulation is added, and the total die components then are compressed fiiUy. Such procedures are used when the tablet ingredients may be incompatible, which requires separate granulations. If needed, a layer of inert ingredient, eg, lactose, is inserted between the two. 

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... 

As a therapeutic agent, ch oline is adininistered orally in the form of symps or elixers containing the chloride, citrates or bitartrate, or in the form of compressed tablets or capsules of the dihydrogen citrate. Choline is also given in small doses as a nutritional supplement in combination with a variety of other materials. In dry pharmaceutical-dosage forms, the dihydrogen citrate is usually preferred because of its lower tendency to absorb atmospheric moisture. Both salts have been used parenteraHy. 

Turkoglu J, Ozarslan R, Sakr A. Artificial neural network analysis of a direct compression tabletting study. Eur J Pharm Biopharm 1995 41 315-22. 

Bourquin J, Schmidli H, van Hoogevest P, Leuenberger H. Pitfalls of artificial neural networks (ANN) modelling technique for data sets containing outlier measurements using a study of mixture properties of a direct compressed tablet dosage form. Eur J Pharm Sci 1998 7 17-28. 

Medications available commercially as compressed tablets can be crushed for administration through feeding tubes. After such a tablet is crushed into a fine powder, it should be mixed with 10 to 30 mL of fluid (usually warm water) for... 

Fig. 16 Effect of lubricant on dissolution of rate of salicylic acid contained in compressed tablets, x, 3% magnesium stearate , no lubricant 0> 3% sodium lauryl sulfate. (From Ref. 21.).

Pharmaceutical compressed tablets are prepared by placing an appropriate powder mix, or granulation, in a metal die on a tablet press. At the base of the die is a lower punch, and above the die is an upper punch. When the upper punch is forced down on the powder mix (single station press) or when the upper and lower... 

Water Uptake. There is evidence to suggest that water uptake caused by capillary forces is the crucial factor in the disintegration process of many formulations. In such systems the pore structure of the tablet is of prime importance and any inherent hydrophobicity of the tablet mass will adversely affect it. Therefore, disintegrants in this group must be able to maintain a porous structure in the compressed tablet and show a low interfacial tension towards aqueous fluids. Rapid penetration by water throughout the entire tablet matrix to facilitate its breakup is thus achieved. Concentrations of disintegrant that ensure a continuous matrix of disintegrant are desirable and levels of between 5 and 20% are common. 

Soft gelatin capsules are not an inexpensive dosage form, particularly when compared to direct compression tablets [3]. There is a more intimate contact between the shell and its liquid contents than exists with dry-filled hard gelatin capsules, which increases the possibility of interactions. For instance, chloral hydrate formulated with an oily vehicle exerts a proteolytic effect on the gelatin shell however, the effect is greatly reduced when the oily vehicle is replaced with polyethylene glycol [3]. 

In this chapter we present the theory involved in developing sustained- and controlled-release delivery systems and applications of these systems as therapeutic devices. Although suspensions, emulsions, and compressed tablets may demonstrate sustaining effects within the body compared with solution forms of the drug, they are not considered to be sustaining and are not discussed in this chapter. These systems classically release drug for a relatively short period, and their release rates are strongly influenced by environmental conditions. 

Bindschaedler and Gurny [12] published an adaptation of the simplex technique to a TI-59 calculator and applied it successfully to a direct compression tablet of acetaminophen (paracetamol). Janeczek [13] applied the approach to a liquid system (a pharmaceutical solution) and was able to optimize physical stability. In a later article, again related to analytical techniques, Deming points out that when complete knowledge of the response is not initially available, the simplex method is probably the most appropriate type [14]. Although not presented here, there are sets of rules for the selection of the sequential vertices in the procedure, and the reader planning to carry out this type of procedure should consult appropriate references. 

Compressed tablets continue to enjoy the status of being the most widely used oral dosage form. Tablets are solid oral... 

Dansereau, R., Peck, G. The Effect of the variability in the physical and chemical properties of magnesium stearate on the properties of compressed tablets. Drug Dev. Ind. Pharm.,13(6), 1987, 975-999. 

Tablets are solid dosage forms that are compressed or prepared by a sintering proeess, including sublingual, buccal, chewable, effervescent, and compressed tablets. Some of these ean be easily compoimded an example of a tablet triturate is as follows ...

Khan, K.A., and Rhodes, C.T., Effect of variation in compaction force on properties of six direct compression tablet formulations, J. Pharm. Sci., 65 1835-1837 (1976). 

Compression Tablet porosity (%) Percentage degradation after 3 h... 

Davies, W.L. and Gloor, W.T., Batch production of pharmaceutical granulations in a fluidized bed, II. Effects of various binders and their concentrations on granulations and compressed tablets, /. Pharm. Sci., 61 (1972) 618-622. 

Wurster, D.E., Preparation of compressed tablet granulations by the air-suspension technique II, /. Am. Pharm. Assoc., 49 (1960) 82-84. 

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