Polyvinyl Acetate Phthalate

Synonyms: Phthalavin; PVAP; Opaseal; Sureteric. 

Description: Polyvinyl acetate phthalate is a free-flowing white to off-white powder and may have a slight odor of acetic acid. The material is essentially amorphous.

Chemical Name: Polyvinyl acetate phthalate

Coating agent.

• Polyvinyl acetate phthalate is a viscosity-modifying agent that is used in pharmaceutical formulations to produce enteric coatings for products and for the core sealing of tablets prior to a sugar-coating process.

• Polyvinyl acetate phthalate does not exhibit tackiness during coating and produces strong robust films.

• Plasticizers are often included in polyvinyl acetate phthalate coating formulations to enable a continuous, homogeneous, noncracking film to be produced.

• Polyvinyl acetate phthalate has been shown to be compatible with several plasticizers such as glyceryl triacetate, triethyl citrate, acetyl triethylcitrate, diethyl phthalate and polyethylene glycol 400.

• For enteric coating applications, polyvinyl acetate phthalate is dissolved in a solvent system together with other additives such as diethyl phthalate and stearic acid.

• Methanol may be used as the solvent if a colorless film is required; for a colored film, methanol or ethanol/water may be used depending on the amount of pigment to be incorporated.

• A weight increase of up to 8% is necessary for nonpigmented systems, whereas for pigmented systems a weight increase of 6% is usually required.

• A formulated, aqueous-based coating solution ( Sureteric, Colorcon) is available commercially for the enteric coating of tablets, hard and soft gelatin capsules and granules.

• More recently, hot-melt extrusion of coating polymers, such as polyvinyl acetate phthalate, has been described for the enteric coating of capsules.

Polyvinyl acetate phthalate reacts with povidone to form an insoluble complex that precipitates out of solution; benzocaine is also incompatible with polyvinyl acetate phthalate. Erythromycin disperses in polyvinyl acetate phthalate and has been shown to be physically stable while omeprazole exists in the amorphous form in polyvinyl acetate phthalate coatings with no evidence of interaction.

Polyvinyl acetate phthalate is used in oral pharmaceutical formulations and is generally regarded as an essentially nonirritant and nontoxic material when used as an excipient.

Observe normal precautions appropriate to the circumstances and quantity of material handled. Gloves and eye protection are recommended.

Cellulose acetate phthalate; hypromellose phthalate; polymethacrylates; shellac