The tensile strength of a tablet is an important attribute as the tablet needs to be mechanically strong enough to withstand further handling. Crumbling and breaking needs to be avoided during film–coating, packaging, transport and end-use by the patient.
Typically, a tablet tensile strength greater than 1.0-1.5 MPa is strong enough to withstand commercial manufacture and subsequent distribution. During friability testing, a mean weight loss of not more than 1.0% is considered acceptable for most products.
Tablet tensile strength and friability is the result of physical chemical properties of the formulation and the process settings that are used for compaction. Tablet tensile strength and friability can be improved by adjustment of the formulation or process parameters.
- Select excipients with highest compaction
- Use SuperTab® 40LL as most compactible soluble filler
- Use SuperTab® 24AN as most compactible lactose filler
- Increase the amount of filler in the formulation, by increasing tablet weight and size
- Add or increase the amount of tablet binder in the formulation
- Increase Pharmacel® content of a lactose based formulation
- Reduce lubrication amount for lubricant sensitive formulations
Compaction can also be improved by adjustment of process parameters
- Reduce lubrication blending intensity for lubricant sensitive formulations
- Increase compaction force
- Optimise pre-compaction
- Increase dwell time by reducing tableting speed
- Change tablet shape