Comparison of dispersive, polar and total surface energies and work of cohesion of (A) coarse lactose and (B) micronized lactose before and after storage at 75% RH (before storage sample was conditioned at 0% RH for 2 h while after storage sample was conditioned at 75% RH for 2 h) (n = 3, data are shown as mean with standard deviation by error bar) (before storage data were shown for comparison).