Physicochemical insights into the micelle-based drug-delivery of bioactive compounds to the carrier protein

Abstract

Micelles can be effectively used as drug delivery systems due to their ability to encapsulate a wide range of drugs. In addition, they can carry and deliver therapeutics to the site of action and hence enhance the therapeutic potential of the loaded drug. Physicochemical insights into the partitioning of drugs into micelles are important for designing efficient drug delivery systems. Micelles can be formulated with improved drug loading and drug delivery capabilities by modifying the hydrophobicity and hydrophilicity of the micelle. In this background, we have studied the partitioning of a bioactive compound, syringic acid, into a cationic micelle hexadecyltrimethylammonium bromide (HTAB), non-ionic micelle Triton X-100 (TX-100) and mixed micelle (HTAB + TX-100) in the temperature range of 288.15–310.15 K using a combination of spectroscopy and calorimetry. The partitioning parameters standard molar enthalpy, standard molar entropy, standard molar Gibbs free-energy change, and stoichiometry of partitioning obtained from isothermal titration calorimetry provide insights into the nature of the interactions involved and the mechanism of partitioning. The partitioning of syringic acid also affects the CMC of the surfactant, which additionally depends on the surface characteristics of the micelles. The fluorescence and ITC results showed that HTAB and TX-100 micelles also modulate the delivery of syringic acid to the carrier protein HSA, which can further be tuned as per the therapeutic need by using mixed (HTAB + TX-100) micelles. Such kinds of physicochemical insights into the drug partitioning followed by its delivery to the protein are essential for the broader objective of developing more efficient drug delivery systems.