Understanding the partitioning of polyamines in micelles and delivery to the carrier protein: Thermodynamic approach

Abstract

Micelle-based drug delivery system is widely used to solubilize and carry a varied range of drugs to the target cells. It selectively delivers drugs to the site of action and hence increases drug bioavailability and reduces the side effects of the drug. In the current work, we have studied the partitioning of two polyamines spermidine and spermine in hexadecyltrimethylammonium bromide (HTAB) micelles followed by their delivery to the carrier protein human serum albumin (HSA) using a combination of spectroscopy and calorimetry. The thermodynamic parameters for the partitioning of the polyamines with the micelles provide information about the nature of interactions of the polyamines with HTAB micelles and monomers. The ITC and docking results suggest that the polyamines sequentially bind with HSA with the values of binding constants in the range of 105 to 102. The binding of these polyamines with HSA gets slightly altered when delivered through HTAB micelles. Fluorescence and CD measurements suggest that the binding of these polyamines does not affect HSA conformation significantly. The results will help in understanding the mechanism of drug partitioning in micellar structures which is essential for developing guidelines to design effective drug delivery systems.