Effervescent tablets compression

Effervescent tablets (compressed effervescent powders) do not represent a solid dosage form, because they are dissolved in water immediately prior to ingestion and are, thus, actually, liquid preparations. 

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 ...

Avoid use of compressed tablets or enteric-coated tablets (i.e., nonsustained release or effervescent tablets for sol) due to significant ulcerogenic tendency and propensity to cause significant local tissue destruction... 

Available as anhydrous and monohydrate anhydrous material used for direct compression due to superior compressibility Originally direct-compression excipient, now often included in granulations due to its excellent compressibihty Direct-compression diluent, often used in chewable tablets Was widely used as sweetener/filler in effervescent tablets and chewable tablets less popular nowadays due to cariogenicity Versatile material that can be used as diluent binder, and disintegtant Brittle material... 

Lozenges These are compressed tablets formulated, without a disintegrant and must be allowed to dissolve in the mouth. They are used for local activity (throat lozenges) or for systemic effect (vitamins). Effervescent tablets These tablets undergo quick dissolution of actives in water due to internal liberation of carbon dioxide. By combining alkali metal carbonates or bicarbonates with tartaric or citric acid, carbon dioxide is liberated when placed in water. 

Soluble, effervescent tablets are prepared by compression. In addition to active ingredients, they contain mixtures of acids (citric acid, tartaric acid) and sodium bicarbonate (NaHCOs) that release carbon dioxide when dissolved in water. The United States Pharmacopeia (USP) 24 includes the following seven monographs Acetaminophen for Effervescent Oral Solution Aspirin Effervescent Tablets for Oral Solution Potassium Bicarbonate Effervescent Tablets for Oral Solution Potassium Bicarbonate and Potassium Chloride for Effervescent Oral Solution Potassium Bicarbonate and Potassium Chloride Effervescent Tablets for Oral Solution Potassium and Sodium Bicarbonates and Citric Acid for Oral Solution and Potassium Chloride, Potassium Bicarbonate, and Potassium Citrate Effervescent Tablets for Oral Solution. ... 

With regard to compressibility and compactibility, the considerations pertaining to raw materials in effervescent products are similar to the ones that prevail in evaluating raw materials intended for conventional tablets. However, poor compactibility cannot usually be compensated for by the use of binders, as this will prevent a rapid dissolution of the effervescent tablet. Addition of a binder is generally not as critical for the dissolution of effervescent granules or powders. 

Some effervescent tablet products are successfully produced by direct compression (e.g., acetylsalicylic acid products). Direct compression normally requires careful selection of raw materials to achieve a free-flowing, non-segregating, compressible mixture. Effervescent products present the same problems as conventional products in direct compression. 

The adaptation of a single-prmch tablet press for compressing effervescent tablets via external lubrication... 

A combination of 4% polyethylene glycol (PEG) 6000 and 0.1% sodium stearyl fumarate proved to be a good lubricant for ascorbic acid tablets made by direct compression on a small scale. Sodium chloride, sodium acetate, and D,L-leucine (water-soluble lubricants) also have been suggested for effervescent tablets. ... 

Twenty lubricants for effervescent tablets were tested for lubrication efficiency in direct compression of a standard effervescent formulation. The lubricant concentration was high as compared to traditional tablet lubricants. By increasing the lubricant concentration... 

Effervescent tablets were produced using four different formulations that contained citric and/or tartaric acid and NaHCOs with polyvidone and PEG 6000. The adhesion of each formulation to the metal faces of the punch tips was determined by means of electron microscopy, surface-roughness measurements, and quantification of punch-weight variations during tablet production. The basic formulations were inherently adhesive and produced tablets with a weak, porous structure the tablets were rougher than conventional, non-effervescent compressed tablets. Both formulations that contained tartaric acid produced tablets with a lower surface roughness and had less... 

During the compression of effervescent tablets, in-process tests are routinely run to monitor the process. These tests include controls of tablet weight, weight variation, thickness, crushing strength, disintegration, and appearance of the tablet. Friability and pH of the solution may be additionally tested. Electronic devices that monitor tablet weight are normally used. 

Saleh, S.I. Aboutaleb, A. Kassem, A.A. Stamm, A. A contribution to the formulation of effervescent tablets by direct compression. Labo-Pharma Probl. Tech. 1984, 32,163-166. 

Dextrates is a directly compressible tablet diluent used in chewable, nonchewable, soluble, dispersible, and effervescent tablets.It is a free-flowing material and glidants are thus unnecessary. Lubrication with magnesium stearate (0.5-1.0% w/w) is recommended. Dextrates may also be used as a binding agent by the addition of water, no further binder being required. ... 

Many solid-dosage forms of potassium chloride exist including tablets prepared by direct compression and granulation effervescent tablets coated, sustained-release tablets " sustained-release wax matrix tablets micro-capsules pellets and osmotic pump formulations. ... 

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. 

Tablets are defined in the Ph. Eur. as solid preparations each containing a single dose of one or more active substances [6]. Tablets are prepared by compressing tmiform volumes of particles or by another suitable manufacturing technique, such as extmsion, moulding or freeze-drying (lyophilisation). The Ph. Eur. distinguishes various types of tablets the most important being uncoated tablets, coated tablets, effervescent tablets, dispersible tablets, gastro-resistant tablets and modified-release tablets.

Precipitated calcium carbonate occurs as line, white, odorless, and tasteless powder or crystals. Its water solubility is very poor, and it is not soluble in ethanol or isopropanol. It is a high density powder, and thus not suitable for compression. It is normally used as a drug in effervescent tablets for patients who suffer from calcium deficiency. It can also be used as alkaline source because it provides stability to the effervescent system (16). 

Lubricant substances which are reported in literature as suitable for effervescent manufacturing because they are water soluble are sodium benzoate, sodium acetate, L-leucine, and Carbowax 4000. A very recent application is a combination of calcium and potassium sorbates, micronized polyethylene glycol with calcium ascorbate or trisodium citrate (20). Combination of spray-dried L-leucine and polyethylene glycol 6000 has been reported as a successful lubricant in the literature (21). Other less soluble lubricants have been used in formulating effervescent tablets, however, a balance should be found between compression efficiency and water solubility. Magnesium stearate is also employed but the most suitable, commercially available type is its combination with sodium lauryl sulfate, a surface-active agent that helps in its dispersion (22). 

An alternate process to dry granulation is direct compression of the blend of all the raw materials, in the attempt to avoid operating and stability problems. It would be the ideal process for effervescent tablet manufacturing, but its application is limited to a few cases, for example, when the active ingredient cannot be granulated (e.g., when it is already included in a complex like with a cyclodextrine), or contains some water of crystallization. 

Tablets manufactured with OraSolv technology should contain an effervescence couple along with microparticles of drug within a rupturable coat. The tablets manufactured are compressed at a low hardness that promotes fast disintegration. The dosage forms need to be packaged in foil-foil aluminum blisters with a dome shape that impact physical protection and impermeability to moisture. This constitutes the PakSolv Techonology. ...

Tablets manufactured with DuraSolv technology contain a non-directly compressible filler and a lubricant. They may or may not contain effervescence, and the drug need not be taste masked. DuraSolv tablets are compressed at higher hardness compared to OraSolv that allows for packaging in bottles or push through blisters.

Effervescent granules can be tableted while still damp since moist citric acid acts as a lubricant. The compressed tablets are transferred immediately and continuously to ovens where they are dried. Drying also hardens them. " ... 

The compression of effervescent mixtures usually results in severe picking and sticking. By means of flat-faced punches with discs of polytetrafluorethylene, the sticking to tablet-punch surfaces is overcome. Other non-adherent materials, such as Vulkollan (a polyethane), Hostalit (polyvinyl chloride), and Resopal (a melamine), have been used. The disc of the plastic material is attached to the recess of the punch surface by glue or adhesive tape. It should be noted that fragments of the polymer can rub off during compression. 

In direct compression, the mixing can be performed at normal humidities however, in that case, the mixture is dried (to prevent a premature effervescent reaction) by means of causing dehumidified air to flow through the bed in a suitable container. Tableting and... 

Sendall, F.E.J. Staniforth, J.N. A study of powder adhesion to metal surfaces during compression of effervescent pharmaceutical tablets. J. Pharm. Pharmacol. 1986, 38, 489-493. 

Joachim J, Kalantzis G, Delonca H, et al. The compression of effervescent aspartame tablets the influence of particle size on the strain applied on the punches during compression [in French]. / Pharm Belg 1987 42 17-28. 

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