While the excipients listed in Table 1 are more likely to be employed in conventional fast-release dosage forms, Table 2 lists categories of excipients (bio-polymers) employed in nonconventional modified-release drug products. From their functional utility point of view, pharmaceutical excipients can be grouped as follows:
fillers,
disintegration promoters,
glidants,
lubricants,
wetting agents,
solubilizers,
viscosity modifiers,
surface-active modifiers,
antioxidants,
preservatives, and
dissolution/release rate modifiers.
Excipients and active ingredients may be present in the dosage form in three different states of dispersion: homogeneous, heterogeneous, and in a specific structure. Likewise, their role and effect may also be different.
In the course of drug formulation, one must consider that the desired effect/functional performance of the drug may be altered by the quantity of an excipient present. The following possible relationships between the quantity
