A modification of the Pr value equation for measuring the compactibility of pharmaceutical materials

Various types of lactose were used to study compactibility using Pr [11]. The dependence of Pr on the compression pressure, used to produce tablets, makes its comparison very difficult and so this phenomenon was studied in detail. It was demonstrated that Pr in its original form is the quotient of two linear functions and has a mathematical dependence on compression force. Therefore, a modification of this equation is proposed (termed Pr′) that increases its practical usefulness. The equation for pressure-independent Pr′ allows for comparison of various materials and/or studies in which different compression pressure values are used, even at low pressures where comparison of Pr itself is not feasible.