Functional Category
Adsorbent; emulsifying agent; viscosity-increasing agent.
Applications in Pharmaceutical Formulation
Hectorite is used widely in pharmaceutical preparations as an absorbent, emulsifier, stabilizer, suspending agent, thickener, and viscosity-controlling agent.(2) Hectorite is a component of other naturally occurring clays and hence may be suitable for use in similar pharmaceutical formulation applications as an adsorbent, oil-in-water emulsifying agent, suspending agent, or viscosity-increasing agent.(3) It is also available as a synthetic material. Hectorite is used to modify the thixotropic behavior of pharmaceutical dispersions(4) and for stabilizing oil-inwater emulsion bases.(5,6) When combined with an appropriat cation, hectorite exhibits properties suitable for use as a contrast agent.
Description
Hectorite is a naturally occurring 2 : 1 phyllosilicate clay of the smectite (montmorillonite) group and is a principal component of bentonite clay. Hectorite occurs as an odorless, white to creamcolored, waxy, dull powder composed of aggregates of colloidalsized lath-shaped crystals.
Stability and Storage Conditions
Hectorite is a stable material and should be stored in a cool, dry place.
Incompatibilities
Contact between hectorite and hydrofluoric acid may generate heat.
Safety
Hectorite is a natural clay mineral that is not considered acutely toxic; therefore no toxicity values have been established. However, hectorite may contain small amounts of crystalline silica in the form of quartz. Dust can be irritating to the respiratory tract and eyes,(8) and contact with this material may cause drying of the skin. Chronic exposure to crystalline silica may have adverse effects on the respiratory system. EU labeling states that the material is not classified as dangerous.