Antacid tablets, formulation

In a series of papers, personnel from Novartis and the University of Basel in Switzerland have highlighted the pros and cons of neural networks for immediate release tablets [37-40]. In other studies neural networks have been found useful in modeling tablet formulations of antacids [41], plant extracts [42], theophylline [43], and diltiazem [44]. In a recent paper Lindberg and Colbourn [45] have used neural networks, genetic algorithms, and neurofuzzy to successfully analyze historical data from three different immediate-release tablet formulations. 

Aluminum oxide is used mainly in tablet formulations. It is used for decoloring powders and is particularly widely used in antibiotic formulations. It is also used in suppositories, pessaries, and urethral inserts. Hydrated aluminum oxide (see Section 18) is used in mordant dyeing to make lake pigments, in cosmetics, and therapeutically as an antacid. 

Tablet formulations account for about 45% of the formulations marketed in the UK with capsules accounting for about 15%. These formulations have the advantage of providing the dose in a discrete unit form that is stable, easily produced and transported and above all easily administered. The tablet is favoured because it is marginally cheaper to produce and slightly more stable under in-use conditions. The simplest solid dosage form is the drug powder itself, a presentation mode that is still used for some antacid preparations. For modem drugs the dose required is too small to be measured accurately by the patient and must therefore be presented preformed.

Tolterodine, available only as a tablet formulation, can be administered with or without food, and the LA product should not be crushed or chewed or taken less than 2 hours before or 4 hours after an antacid. The maximum benefit from tolterodine may not be realized for up to 8 weeks after starting therapy or dose escalation. 

Many over-the-counter antacid tablets are now formulated using calcium carbonate as the active ingredient, which enables such tablets to also be used as... 

USP-grade anhydrous magnesium carbonate is used as a flavor impression intensification vehicle in the processed food industry (see Flavors and spices). Basic magnesium carbonates are used as free flowing agents in the manufacture of table salt, as a hulking agent in powder and tablet pharmaceutical formulations, as an antacid, and in a variety of personal care products (see Pharmaceuticals). 

Chewable Tablets. It has already been noted that most elderly patients experience a decrease in their ability to chew efficiently [125,137,138,143]. Therefore, by virtue of their design, chewable tablets are not often recommended for use by elderly patients (particularly those who are edentulous) 155-163,164], Most chewable formulations also rely on an adequate amount of chewing action to obtain full release of their ingredients (e.g., chewing promotes the foaming action provided by some chewable antacid products). So, aside from being difficult form the elderly patient to use, full benefit of a chewable dosage form may not be achieved by these patients. Additionally, the use of chewable tablets by denture wearers may cause local irritation in the oral cavity [155]. 

Proquin XR Proquin XR and other oral formulations of ciprofloxacin are not interchangeable. Proquin XR should be administered orally once daily for 3 days with a main meal of the day, preferably the evening meal. Proquin XR should be administered at least 4 hours before or 2 hours after antacids containing magnesium or aluminum, sucralfate, Videx (didanosine) chewable/buffered tablets or pediatric powder, metal cations such as iron, and multivitamin preparations containing zinc. Pragy/n XR tablets should be taken whole and never split, crushed, or chewed. 

In pharmaceutical applications, sorbitol is used as a tablet diluent in wet granulation or dry compression formulations. It is commonly used in chewable tablets because of its sweet taste, and it is also used as a plasticizer for gelatin in capsule formulations. Sorbitol is utilized in sugar-free liquid preparations and as a stabilizer for drug, vitamin, and antacid suspensions. When it is used in syrups, crystallization around bottle caps is prevented. 

Foams can occur in the intestines where they may cause indigestion, pain, and/or a sense of being full, collectively known as dyspepsia [884]. Pharmaceuticals designed to combat dyspepsia usually contain antifoams, antacids, and possibly enzymes [884]. The most common antifoams seem to be polymethylsiloxanes (referred to as dimethicone in pharmaceutical literature [884]) mixed with hydrophobic particles, such as hydrophobic silica. The formulation is delivered as a tablet, suspension, or emulsion (simethicone tablets simethicone oral suspensions simethicone emulsions). Foams can also be used to administer drugs, such as in contraceptive foams. 

Chewable tablets. These tablets are preferred for pediatric and geriatric patients who have difficulty swallowing whole tablets. Another advantage is that they do not need water for administration. Mannitol is normally used as the base diluent because of its pleasant taste and texture, and because it can effectively mask the taste of objectionable actives. They are usually prepared by wet granulation and are not compressed very hard. High amounts of flavor are added to increase palatability. Antacids are typically formulated as chewable tablets. 

Therapeutically, simethicone is included in a number of oral pharmaceutical formulations as an antiflatulent, although its therapeutic benefit is questionable. It is also included in antacid products such as tablets or capsules. In some types of surgical or gastroscopic procedures where gas is used to inflate the body cavity, a defoaming preparation containing simethicone may be used in the area to control foaming of the fluids. 

Didanosine chewable tablets contain antacids (aluminium/magnesium hydroxide) in the formulation, but it has been shown that they do not affect the bioavailability of isoniazid. ... 

An extremely marked reduction in the serum levels of ciprofloxacin occurs if it is given at the same time as didanosine tablets, because of an interaction with the antacid buffers in the didanosine formulation. Taking the ciprofloxacin 2 hours before or 6 hours after didanosine tablets minimises this interaction. Other quinolones are expected to interact similarly. Didanosine enteric-coated capsules do not interact with ciprofloxacin. 

When 12 healthy subjeets were given ciprofloxacin 750 mg with two didanosine plaeebo tablets (i.e. all of the antacid additives but no didanosine), the ciprofloxacin AUC and maximum serum levels were reduced by 98% and 93%, respectively. The antacids in this formulation were dihy-droxyaluminium sodium carbonate and magnesium hydroxide. 

Other studies have looked at whether separating the administration times affects this interaction. When 16 HIV-positive patients were given ciprofloxacin 1.5 g daily 2 hours before didanosine tablets, the ciprofloxacin AUC was reduced by only 26%. Another study in just one subject found that when ciprofloxacin 500 mg was given 2 hours after taking two didanosine placebo tablets the ciprofloxacin serum levels were reduced below minimal inhibitory concentrations, but giving the ciprofloxacin 2 hours before the didanosine placebo tablets resulted in normal blood levels. The enteric-coated capsule formulation of didanosine (which does not contain antacids) does not interact with ciprofloxacin. ... 

Some of the didanosine preparations (e.g. chewable tablets) are formulated with antacid buffers that are intended to facilitate didanosine absorption by minimising acid-induced hydrolysis in the stomach. These preparations can therefore alter the absorption of other drugs that are affected by antacids (e.g. azole antifungals, quinolone antibacterials, tetracyclines). This interaction may be minimised by separating administration by at least 2 hours. Alternatively, the enteric-coated preparation of didanosine (gastro-resistant capsules) may be used. 

Didanosine is acid labile. To increase its absorption, some didanosine preparations (e.g. buffered tablets) have been formulated with antaeids. Additional concurrent antacids would not be expeeted to have any further clinically relevant effect on didanosine pharmaeokineties, although the US manufacturers of the oral powder for solution suggest that additional antacids may increase the adverse effects of the eomponents of this preparation (presumably both the antacid and didanosine components). 

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