Floating capsules tablets

Pharmacopeias require that hard capsules be tested in the same apparatus as tablets even though they have very different physical properties. Filled capsules contain entrapped air, and most formulations will float on water. Devices are required to ensure that they sink, and these can influence the results obtained. Gelatin and hypromellose are adhesive materials and tend to block wire meshes that form part of the standard equipment. The way in which capsules disintegrate and dissolve is dependent upon several factors such... 

The apparatus should be capable of allowing the evaluation of disintegrating, non-disintegrating, dense or floating tablets, or capsules and finely powdered drugs. 

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