The breakup of viscous drops in a turbulent regime is a challenging area of research. In this study, the population balance equation is used for modeling of the drop size distribution of emulsification systems in stirred tank. The suitability of various fluid particle breakage closures in the literature is investigated for the prediction of experimental data obtained from emulsification of silicone oils with four different viscosities. Systems with breakup of dispersed-phase drops of high viscous grades call for an improved model framework that allows the breakage closures to adjust correctly for the effect of viscosity. This is particularly required for systems of higher viscosities where the complex effects of viscous breakup are more pronounced.