Food additives Europe numbers: E1203
Functional Category
Coating agent; lubricant; stabilizing agent; viscosity-increasing agent.
Applications in Pharmaceutical Formulation
Polyvinyl alcohol is used primarily in topical pharmaceutical and ophthalmic formulations; see Table II.(1–3) It is used as a stabilizing agent for emulsions (0.25–3.0% w/v). Polyvinyl alcohol is also used as a viscosity-increasing agent for viscous formulations such as ophthalmic products. It is used in artificial tears and contact lens solutions for lubrication purposes, in sustained-release formulations for oral administration,(4) and in transdermal patches.(5) Polyvinyl alcohol may be made into microspheres when mixed with a glutaraldehyde solution.(6)
Description
Polyvinyl alcohol occurs as an odorless, white to cream-colored granular powder.
Stability and Storage Conditions
Polyvinyl alcohol is stable when stored in a tightly sealed container in a cool, dry place. Aqueous solutions are stable in corrosionresistant sealed containers. Preservatives may be added to the solution if extended storage is required. Polyvinyl alcohol undergoes slow degradation at 1008C and rapid degradation at 2008C; it is stable on exposure to light.
Incompatibilities
Polyvinyl alcohol undergoes reactions typical of a compound with secondary hydroxy groups, such as esterification. It decomposes in strong acids, and softens or dissolves in weak acids and alkalis. It is incompatible at high concentration with inorganic salts, especially sulfates and phosphates; precipitation of polyvinyl alcohol 5% w/v can be caused by phosphates. Gelling of polyvinyl alcohol solution may occur if borax is present.
Safety
Polyvinyl alcohol is generally considered a nontoxic material. It is nonirritant to the skin and eyes at concentrations up to 10%; concentrations up to 7% are used in cosmetics. Studies in rats have shown that polyvinyl alcohol 5% w/v aqueous solution injected subcutaneously can cause anemia and infiltrate various organs and tissues.(7) LD50 (mouse, oral): 14.7 g/kg LD50 (rat, oral): >20 g/kg