Starch, maize

• BPMaize Starch
• JPCorn Starch
• Ph. Eur.Maize Starch
• USP–NFCorn Starch

amylum maydis; corn starch; maize starch; Pure-Dent; Purity 21

Starch (a polysaccharide composed of amylose and amylopectin) · [9005-25-8]

(C6H10O5)n

Diluent (filler), Disintegrant, Binder

Typical concentrations: — · Dosage forms: Solid

A versatile excipient in oral solid dosage forms, used as a diluent, binder and disintegrant, and also as a glidant and in dusting powders. Typical concentrations: tablet disintegrant 3–25% w/w (often about 5–15%); binder, added as a freshly prepared paste in wet granulation, 5–25% w/w; diluent in tablets and capsules at higher levels. It is also used as a thickener in foods and as a component of topical dusting powders.

An odourless, tasteless, fine white to off-white powder. Under the microscope the granules are polyhedral or rounded, roughly 2–30 µm across, with a central hilum, and show a dark cross between crossed polarisers. Normal maize starch contains roughly one-quarter amylose and three-quarters amylopectin.

Particle size

granules ≈ 2–30 µm

Moisture content

typically 10–14% at ambient humidity; Ph. Eur. loss on drying not more than 15%

pH

4.0–7.0 (aqueous slurry)

Gelatinisation temperature

about 62–72 °C

Solubility

practically insoluble in cold water and ethanol; swells in water and forms a paste on heating

Dry starch is stable if protected from high humidity and is considered chemically and microbiologically inert under normal storage. Starch pastes and solutions are physically unstable (they retrograde) and readily support microbial growth, so they should be freshly prepared. Store in an airtight container in a cool, dry place.

Incompatible with strongly oxidising substances. It forms coloured inclusion complexes with iodine.

Obtained by wet milling of maize kernels: the grain is steeped in warm water containing a little sulfur dioxide, coarsely milled, and the germ, fibre and protein (gluten) are separated. The starch slurry is washed, dewatered and dried.

Starch is an everyday food and is regarded as non-toxic and non-irritant. Starch powder used on surgical gloves has caused granulomas and peritonitis, and allergic reactions to maize starch are rare.

Observe normal precautions for the quantity handled. Avoid generating dust, which may irritate the eyes and can form explosive mixtures with air; eye protection and a dust mask are recommended.

A common food ingredient. Included in the FDA Inactive Ingredient Database (oral capsules, powders, suspensions and tablets; topical and vaginal preparations) and in non-parenteral medicines licensed in Europe.

Potato starch; pregelatinised starch; rice starch; sodium starch glycolate; wheat starch; starch, sterilisable maize.

Native maize starch flows and compresses poorly, so it is seldom used alone in direct compression; pregelatinised starch is preferred there. As a disintegrant it works mainly by wicking and limited swelling and is more effective when part is added extragranularly. Its moisture content can be transferred to moisture-sensitive drugs.