Sodium Starch Glycolate Type A

Category

Disintegrants; Suspending Agentss

Molecular Weight

5×10^5~1×10^6

Grade

Pharmceutical Excipients

Description

Sodium starch glycolate is a white or almost white free-flowing very hygroscopic powder.

UNII

N/A

Chemical Name

Sodium carboxymethyl starch

CAS Number

9063-38-1

Synonyms

Carboxymethyl starch, sodium salt Type A

Administration route

Oral

Dosage Form

Oral capsules and tablets

Stability and Storage Conditions

Tablets prepared with sodium starch glycolate have good storage properties. 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.

Source and Preparation

Sodium starch glycolate is a substituted derivative of potato starch. Typically, commercial products are also crosslinked using either sodium trimetaphosphate (Types A and B) or dehydration (Type C). Starch is carboxymethylated by reacting it with sodium chloroacetate in an alkaline, nonaqueous medium, typically denatured ethanol or methanol, followed by neutralization with citric acid, acetic acid, or some other acid. Vivastar P is manufactured in methanolic medium, and Explotab in ethanolic medium.

Applications

Sodium starch glycolate is widely used in oral pharmaceuticals as a disintegrant in capsule and tablet formulations. It is commonly used in tablets prepared by either direct-compression or wet-granulation processes.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. 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. Sodium starch glycolate has also been investigated for use as a suspending vehicle.

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.

Incompatibilities

Sodium starch glycolate is incompatible with ascorbic acid.