What characteristic best describes the relationship that governs compactability?

The relationship that best describes compactability is characterized by tensile strength and solid fraction. When formulating tablets, compactability refers to the ability of a powder to form a solid tablet under pressure. The solid fraction is an important parameter, as it indicates the volume of the particles that contributes to the compact structure.

Tensile strength, which refers to the resistance of a material to breaking under tension, is a key indicator of how well the particles can bond together when compacted. A high tensile strength in relation to a given solid fraction suggests that the powder can produce a robust tablet, while a lower tensile strength may indicate weaker tablets that are more prone to crumbling or breaking.

This relationship between tensile strength and solid fraction is foundational in tablet formulation, as it influences the mechanical properties, performance, and dissolution characteristics of the final dosage form. Understanding how these two factors interact allows pharmaceutical scientists to optimize formulations for desired outcomes.