A disruption index for quantifying the solid state disorder induced by additives or impurities. I. Definition and evaluation from heat of fusion

摘要: A dimensionless disruption index (d.i.) is proposed for quantifying the solid state disorder induced by an additive or impurity (the guest substance), when present in solution crystal lattice of a host substance at mole fractions, x2, less than 0.05. The d.i. value defined as rate change difference between entropy and that liquid, with respect to ideal mixing components solid, ΔSmideal. From fundamental thermodynamic considerations closely approximated slope plot fusion ΔSf, against ΔSmideal x2 < ΔSf given heat divided absolute melting point, while = − RΣxj ln xj calculated from analytical data crystals, where fraction component. linear relationship was tested using limited literature available 7 systems found be obeyed Values range zero solutions through about 10−1 doping intermetallic compound InCd3 either its components, (somewhat higher, 0.423, cadmium doped InCd3), 10 stable, ordered organic additive. values phenacetin benzamide, griseofulvin + lecithin, acetaminophen water p-acetoxyacetanilide, pp-DDT op-DDT, are 7.94, 5.09, 6.53 15.1, respectively. discussed relation properties guest. method determining critically assessed. may useful predicting sensitivity drug excipient presence traces solution. If impurities gives rise batch-to-batch variations, also observed differences batches materials.