Most pharmaceutical capsules are made from gelatine. These material dissolve in the low pH gastric juices in the stomach. But, for certain purposes capsules are designed to pass through the stomach and into the intestine before dissolving, such products are described by a variety of terms, including gastric resistant, entero soluble, delayed release, and enteric capsules. Enteric capsules are used when the drug may irritate the gastric mucosa. Enteric capsules also used when the drug is inactivated by gastric fluid (such as stomach acid).
In this sesion it will be discussed about the hard alginate capsule shell. Hard alginate capsules are made from sodium alginate. Sodium alginate is a sodium salt of alginic acid. Alginic acid is a polysaccharide that is derived from seaweed (brown algae) and it is non-toxic, biodegradable, and biocompatible.
The preparation, physical properties, and the application of hard alginate capsules shell as enteric capsules. The physical properties of hard alginate capsules shell such gastric resistance in vitro and in vivo, disintegration in vitro, britleness, equilibrium moisture content, water vapour permeability, and drug release will be discussed. Furthermore, drug biovailability and the safety to the stomach in animal experiment will be also discussed. As drugs model are used that drugs are irritating the gastric mucosa, namely nonsteroidal antiinflamatory drugs (aspirin, indomethacin, mefenamic acid) and FeSO4 antianemic drug.