Functional Category
Tablet and capsule disintegrant.
Applications in Pharmaceutical Formulation
Sodium starch glycolate is widely used in oral pharmaceuticals as a disintegrant in capsule(1–6) and tablet formulations.(7–10) It is commonly used in tablets prepared by either direct-compression(11–13) or wet-granulation processes.(14–16) The usual concentration employed in a formulation is between 2% and 8%, with the optimum concentration about 4%, although in many cases 2% is sufficient. Disintegration occurs by rapid uptake of water followed by rapid and enormous swelling.(17–20) Although the effectiveness of many disintegrants is affected by the presence of hydrophobic excipients such as lubricants, the disintegrant efficiency of sodium starch glycolate is unimpaired. Increasing the tablet compression pressure also appears to have no effect on disintegration time.(10–12) Sodium starch glycolate has also been investigated for use as a suspending vehicle.(21)
Description
Sodium starch glycolate is a white or almost white free-flowing very hygroscopic powder. The PhEur 6.0 states that when examined under a microscope it is seen to consist of: granules, irregularly shaped, ovoid or pear-shaped, 30–100 mm in size, or rounded, 10–35 mm in size; compound granules consisting of 2–4 components occur occasionally; the granules have an eccentric hilum and clearly visible concentric striations. Between crossed nicol prisms, the granules show a distinct black cross intersecting at the hilum; small crystals are visible at the surface of the granules. The granules show considerable swelling in contact with water.
Stability and Storage Conditions
Tablets prepared with sodium starch glycolate have good storage properties.(22–24) Sodium starch glycolate is stable although very hygroscopic, and should be stored in a well-closed container in order to protect it from wide variations of humidity and temperature, which may cause caking. The physical properties of sodium starch glycolate remain unchanged for up to 3 years if it is stored at moderate temperatures and humidity.
Incompatibilities
Sodium starch glycolate is incompatible with ascorbic acid.(25)
Safety
Sodium starch glycolate is widely used in oral pharmaceutical formulations and is generally regarded as a nontoxic and nonirritant material. However, oral ingestion of large quantities may be harmful.