Condensation on soluble nuclei has been considered taking into account the adsorption of nucleus substance at the drop surface. Nucleation thermodynamics has been investigated for the case of the strong adsorption unsaturation. Principles of thermodynamics of condensation on a soluble nuclei have been formulated for the case arbitrary degree of adsorption saturation. A general thermodynamic expression for extreme value of the chemical potential of condensate was found. Closed system of equations connecting thermodynamic characteristics of the drop having the extreme value of condensate chemical potential was derived. The limiting case of complete saturation of adsorption has been considered.