The Lockhart-Martinelli type model originally proposed for two-phase pressure drop estimation in the high interaction regime by Pinna et al. [AIChE J. 2001, 47, 19-30] is modified and extended to high as well as low interaction regimes. The proposed modified model contains an adaptive parameter, alpha(m). The two-phase pressure drop is related to the Lockhart-Martinelli parameter and liquid saturation. The experimental data corresponding to the two-phase pressure drop and dynamic liquid saturation, for an air-water system on different packings are used to determine the values of alpha(m) for each packing under low and high interaction regimes. It is observed that with decrease in particle sphericity the adaptive parameter, alpha(m), increases for the same hydrodynamic regime. The variation of adaptive parameter, alpha(m), for a particular packing with respect to adaptive parameter, alpha(sph), for spherical packing is found to be a function of particle sphericity.