Glidant

Soluble lubricants Adipic acid d, /-Leucine Glyceryl triacetate Magnesium lauryl sulfate PEG 400, 6000, and 8000 Polyoxyethylene monostearates Sodium benzoate Sodium lauryl sulfate Sucrose monolaurate Glidants... 

Starches remain a popular glidant, in particular those with the larger grain sizes such as potato starch, possibly because of their additional value as a disin-tegrant in the formulation. Concentrations up to 10% are common, but it should be appreciated that excess may result in exactly the opposite effect of that desired (i.e., flow properties may worsen). Talc is also widely used and has the advantage that it is superior to starches in minimizing any tendency for material to stick... 

Note Colloidal silica (glidant) and sodium starch glycolate (disin-tegrant) were fixed at 0.1% and 5%, respectively, in all batches. Source. Ref. 100. 

K Ito, S-I Kaga, Y Takeya. Studies on hard gelatin capsules II. The capsule filling of powders and effects of glidant by ring filling machine-method. Chem Pharm Bull 17 1138-1145, 1969. 

P York. Application of powder failure testing equipment in assessing effect of glidants on flowability of cohesive pharmaceutical powders. J Pharm Sci 64 1216-1221, 1975. 

HM Sadek, JL Olsen, HL Smith, S Onay. A systematic approach to glidant selection. Pharm Tech 6(2) 43-62, 1982. 

Excipients are sub-divided into various functional classifications, depending on the role that they are intended to play in the resultant formulation, for example, fillers, disintegrants, binders, lubricants and glidants. An added complexity is the fact that certain excipients can have different functional roles in different formulation types. Thus, lactose is widely used as a filler or diluent in solid oral dosage forms, for example, tablets and capsules [2] and as a carrier for inhalation products [3]. 

Excipients play a key role in oxidation, either as a primary source of oxidants, trace amounts of metals, or other contaminants. Auto-oxidation of diethylstilbes-terol to the peroxide and conjugated quinone degradation products was attributable to the presence of colloidal silicon dioxide, used as a glidant in solid oral dosage forms [48]. This was ascribed to the fact that silicon dioxide can act as a Lewis acid (an election acceptor or oxidising agent), under anhydrous conditions. 

Glidant Aids powder flow properties during manufacture Colloidal silica, starch... 

To motivate the response surface approach, suppose that there is some response of interest (for example, crushing strength in the tablet formulation example of Section 2.1.1), and a set of quantitative, continuous design variables that are of interest to the researcher (for example, the quantities of glidant, lactose, and disintegrant for the tablet formulation example). One possible objective for the researcher might be to understand and describe the relationship between the design variables and the response. This relationship can be described mathematically by... 

Run Binder (%) Lubricant (%) Disinte-grant (%) Glidant (%) Water (%) Compression force (kN) Disintegration Hardness (Kp) time (secs) Friability (%) ... 

Glidants (e.g., colloidal silicon dioxide, talc) may need to be added to achieve desired flow properties, especially when the drug/filler ratio is relatively high. Usually, there is an optimum concentration of glidant for best flow, often less than 1% for the colloidal silicas (14,15). The following order of effectiveness of glidants has been reported for two powder systems fine silica > magnesium stearate > purified talc (16). 

An example of interactive mixing between two excipients is the interaction between fumed silica and other components in the formulation. At low concentrations, e.g., 0.05% to 0.1%, the fumed silica is an effective glidant. It appears to function by being adsorbed onto the surface of the other components and thereby disrupting the cohesive forces within the powder bed. However, above 1% the fumed silica may begin to impede the flow, because the available adsorption sites are occupied and the excess material is mixed in with the rest of the components. On its own, fumed silica does not flow well. 

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