Sugar spheres

• BPSugar Spheres
• Ph. Eur.Sugar Spheres
• USP–NFSugar Spheres

Non-pareil seeds; non-pareils; sugar seeds; sacchari sphaerae; Nu-Core; Nu-Pareil; Suglets

Spherical granules made of sucrose and starch (usually maize starch) · [—]

Polymer, mixture or material of variable composition — no single molecular formula applies.

Diluent (filler)

Typical concentrations: — · Dosage forms: Solid

Used mainly as inert starter cores on which a drug, and then a release-controlling or enteric film, is layered in a coating pan or fluid-bed coater. The coated pellets are filled into hard capsules or compressed into tablets to give multiparticulate modified-release products.

Hard, brittle, free-flowing, white or almost white spheres. Each sphere consists of sucrose built up in layers, together with starch; colourants may be present in some grades. The material is odourless and has a sweet taste.

Particle size

supplied as narrow sieve fractions, typically between about 200 µm and 2000 µm; the labelled range must be met

Sucrose content

USP-NF: not more than 92% (dried basis); Ph. Eur.: 62.5–91.5%, the remainder being mainly starch

Loss on drying

low; not more than 4% w/w (USP-NF)

Solubility

the sucrose fraction dissolves readily in water, while the starch fraction is insoluble, so the cores soften and partly disintegrate in water

Flow

excellent, owing to the spherical shape and narrow size distribution

Stable when kept dry. Sucrose is hygroscopic and the spheres may cake or soften at high humidity. Store in a well-closed container in a cool, dry place.

Shares the incompatibilities of sucrose. Partial inversion of sucrose, favoured by acid, heat and moisture, produces reducing sugars that can undergo Maillard reactions with amine-containing drugs.

Made by building up layers of sucrose syrup and starch dispersion, or a sucrose–starch powder, onto fine sucrose crystals rotating in a coating pan, followed by drying and sieving into size fractions.

Regarded as non-toxic and non-irritant at the levels used in oral products. The sucrose content should be considered for diabetic patients and for dental health in chewable or long-term paediatric products.

Observe normal precautions for the quantity handled. Dust generated during handling may irritate the eyes; eye protection and gloves are recommended.

Included in the FDA Inactive Ingredient Database (oral capsules and tablets) and in non-parenteral medicines licensed in Europe.

Sucrose; compressible sugar; confectioner's sugar; microcrystalline cellulose spheres.

Size uniformity and sphericity of the cores directly affect coating uniformity and hence drug release, so suppliers' size cuts should be specified tightly. Because the cores partly dissolve, they can raise osmotic pressure inside a film-coated pellet; for drugs or coatings where this matters, microcrystalline cellulose or other insoluble cores may be preferred.