From the theoretical point of view, characterization of nano particle interaction depends much on the particle diameter , packing factor , the parameter of the Lennard-Jonnes (LJ) pair potential function (r) and static structure factor S (Q). A novel method suggested in this paper has been tested on seven specific drug delivering fluorocarbons by estimating the strength of interaction /k of (r) and S(Q) in terms of the elementary parameter . The importance of this paper is that, the input parameter viz., packing factor has been obtained from the experimental ultrasonic velocity of those seven systems. Calculations were extended for different temperatures involving four different equations of states to back up the application of the model. Though there is a lack of analytical results to compare, our predictions are encouraging.