Applicability of Direct Compression

Direct Compression is typically useful when the dose of the API is a small proportion of the weight of the tablet. In such cases the tableting properties are largely determined by the properties of the excipients used.

As a guide the doses that might be thought of suitable for DC are in the range of approximately 0.5mg to approximately 50mg, the upper end representing 20% of the weight of a typical tablet of 250mg with a diameter of about 9mm.

Above this dose some adverse properties of the API may become apparent in the tableting process, either as poor flow of the compression mix on the tablet machine or in reduced compactability.

At very low doses some formulators have a fear that poor drug content uniformity may result either through poor mixing and distribution of the drug, or through segregation of the drug and the excipients.