For PMMA plates, it
is probably possible to improve the correspondence between in
vitro and label values by using a different amount of product or
different roughness. Heinrich and co-workers [13] obtained the
best correlation in vitro/in vivo by using an amount of 1 mg/cm2 for
emulsion type screen; for other formulations (as sprays and oils),
the best correlation was obtained using an amount of 0.5 mg/cm2.