Tablet colloidal silica

Lerk CF, Bolhuis GK, Smedema SS. Interaction of lubricants and colloidal silica during mixing with excipients I. Its effect on tableting. Pharm Acta Helv 1977 52(3) 33-39. 

Like lubricants, glidants are fine powders and may be required for tablet compression at high production speeds to improve the flow properties of the material into the die or during initial compression stages. They are added in the dry state immediately prior to compression and, by virtue of their low adhesive potential, reduce the friction between particles. Colloidal silica is popular, as are starches and talc. 

Tablet glidant Agent used in tablet and capsule formulations to improve flow properties of powder mixture Colloidal silica, corn starch, talc...

Excipients that aid powder flow in tablet or capsule manufacture. Materials such as colloidal silica improve flow from hopper to die and aid packdown in the die or capsule shell. Accuracy and consistency of fill and associated dose is thereby improved. 

Johansson ME, Nicklasson M. Influence of mixing time, particle size and colloidal silica on the surface coverage and lubrication of magnesium stearate. In Rubinstein MH, ed. Pharmaceutical Technology Tableting Technology. Chichester Ellis Horwood, 1987 43-50. 

Agglomeration might be the cause of poor flowability, for instance of a powder mixture for filling of capsules or tablet dies. The addition of anhydrous colloidal silica (Aerosil 200V) may be effective for the dispersion of agglomerates. Silica is added to 0.5-1 % (w/w) of the total weight of active substance and excipients. 

Morphine sulphate in a matrix of a fatty base (Witepsol W25) with colloidal anhydrous silica (Aerosil R 972 ) and hydroxypropylmethylceUulose (HPMC 4000) [10] showed an absorption rate and a biological availability equivalent to orally given morphine sulphate retard tablets (MS Contin ). Such suppositories can be made as a regular pharmacy preparation [11] but in our opinion this requires more convincing evidence that morphine release is sufficiently reproducible. MS-Contm suppositories (not available in all countries) have a fatty base with sodium alginate and calcium phosphate [12]. 

Colloidal anhydrous silica (colloidal silicon oxide) and magnesium stearate are used as lubricants in the preparation of capsules, tablets and powders (see Sect. 4.4.3). Addition of lubricants in the preparation of capsules, powders and tablets usually leads to a smoother fill of the capsules, or the moulds. An additional advantage is the reduction of the losses as a result of the elimination of the static charge of the powder mixture. 

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