Thermodynamic stability of ibuprofen loaded poloxamer micelles

Thermodynamic stability of poloxamer micelles excluding and encapsulating ibuprofen drug at different concentrations is studied by means of free energies. Free energies are computed by a partitioning of the total free energy in order to consider the different parts of the co-polymers together with free co-polymer chains in solvent. Moreover, extra terms to the free energy are added to account for the drug-micelle and drug-solvent interactions. The thermodynamic stability of the system is found to be positively correlated with the drug loading for the same system. The RDFs computed between water and the drug molecules signify the decreasing neighboring between these pairs as the co-polymer and drug concentrations are increased in the mixtures as the system leans towards a higher thermodynamic stability. In this work, not only the thermodynamic stability but also its relation to the structure are discussed for a drug-laden system demonstrating the utility of the proposed procedure.