Oral administration effervescent preparations

Figure 9.7 Intragastric pH after administration of (O) effervescent cimetidine and ( ) standard cimetidine, plotted as median values from 13 patients with gastro-oesophageal flux given 800 mg orally of the preparations.

Concerning Virtual CT gastroscopy best results are obtained by the oral administration of effervescent powders. In any case, attention must be given to the fact that extensive gastric fluid may produce an air-fluid level that prevents the reconstruction of the underlying mucosa. Consequently, the patient should be properly prepared with a 12-h fast and ingestion of a very small amount of water with the effervescent powder, and two spiral acquisitions, with the patient in both the supine and prone, or better in the left posterior oblique position, should be acquired (Kim AY... 

There are other forms in which effervescence is based on a reaction different from carbon dioxide formation. Effervescence is due to reactants that evolve oxygen or other gases, which are safe for human consumption even if they are not suitable for oral administration but can be employed in preparations for external use such as antibacterial for dental plate cleaning. 

Recently, some effervescent systems have been prepared that act as penetration enhancers for drug absorption, not only in oral forms but also in some topical forms, such as skin or vaginal applications. In these cases the reaction takes place directly after administration, in the mouth due to saliva (4), upon the wounds due to blood serum (5), or when formulated in a suppository. The effervescence can be provoked by the moisture of the vaginal mucosa to treat vaginal infections or by simply adjusting the pH. 

Sodium phosphate is prepared from the mineral phosphorite which is a tribasic calcium phosphate. The phosphatic material is digested with sulfuric acid, the mixture is then leached with hot water, neutralized with sodium carbonate, and the sodium phosphate is crystallized from the filtrate. It is the active ingredient in Effervescent Sodium Phosphate, one of the most pleasant of the saline laxatives. It is also used in the preparation of Sodium Phosphate Oral Solution. This solution, which corresponds to 0.75g of the official hydrated salt in each ml. provides an easy form for the administration of a saline laxative and antihypercalcemic (Gennaro, 1990). 

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See also in sourсe #XX -- [ ]

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