Cellulose Acetate Phthalate (CAP), also known as cellacefate and cellulosi acetas phthalas, is a commonly used polymer phthalate in the formulation of pharmaceuticals, such as the enteric coating of tablets or capsules and for controlled release formulations.
Its main use in pharmaceutics is with enteric formulations. It can be used together with other coating agents, e.g. ethyl cellulose. Cellulose acetate phthalate is commonly plasticizedwith diethyl phthalate, a hydrophobic compound, or triethyl citrate, a hydrophilic compound; other compatible plasticizers are various phthalates, triacetin, dibutyl tartrate, glycerol, propylene glycol, tripropionin, triacetin citrate, acetylated monoglycerides, etc.
- CAP has been used for several decades as a pharmaceutical excipient due to its solubility dependent on the pH of the aqueous media. Enteric coatings based on CAP are resistant to acidic gastric fluids, but easily soluble in mildly basic medium of the intestine. The pH sensitive solubility of CAP is mainly determined (as other properties of this mixed ester) by the degree of substitution (DS), namely the average number of substituent groups bound to an anhydroglucose unit (AGU), as well as by the molar ratio (acetyl and phthaloyl groups). These two structural characteristics of the polymer are dependent on the method employed for its synthesis.
Recently, its potential to inhibit infections by human immunodeficiency virus type 1 (HIV-1) and several herpes viruses in vitro have been investigated.
(CAP), also known as cellacefate
Source: Wikipedia, https://en.wikipedia.org/wiki/Cellulose_acetate_phthalate