Strict relations which connect thermodynamic characteristics needed for condensation kinetics of supersaturated vapour on soluble surfactant nuclei were deduced. Relations obtained are not limited by specific type of adsorption isotherm of nucleus's substance on the surface of drop forming on the nucleus. Algorithm for calculation of thermodynamic characteristics of condensation kinetics depending on the external condensation conditions is proposed on the basis of the relationships. This algorithm was applied for the construction of asymptotics of thermodynamic characteristics at two extreme situations when the adsorption of nucleus' substance is greatly unsaturated or there is almost total adsorption of the substance on the drop surface.