Drug products usually contain inactive, non-medicinal substances other than the therapeutic agent(s). These substances are called excipients, and they are intentionally included in a drug product to serve different pharmaceutical purposes, thus ensuring product acceptability in terms of manufacturability, appearance and performance.
In tablet formulation, excipients are usually combined at various quantities with the active drug substance(s) to produce tablets that are of standard quality. The type and quantities of each excipient used depend on the type of tablet desired and the process employed.
Classes of excipients used in the manufacture of tablets
Excipients used in tablet formulation may be classified into two groups:
- Those that help to impart satisfactory processing and compression characteristics to the formulation e.g. bulking agents/diluents, binders, glidants, and lubricants.
- Those that help to give additional desirable physical characteristics to the compressed tablets e.g., disintegrants, surface acting agents/ surfactants, colours, flavours and sweetening agents (as in the case of chewable tablets), polymers or hydrophobic materials (as in the case of controlled-release tablets).