Analysis of drug interactions with very low density lipoprotein by high-performance affinity chromatography

Abstract

High-performance affinity chromatography (HPAC) was utilized to examine the binding of very low density lipoprotein (VLDL) with drugs, using R/S-propranolol as a model. These studies indicated that two mechanisms existed for the binding of R- and S-propranolol with VLDL. The first mechanism involved non-saturable partitioning of these drugs with VLDL, which probably occurred with the lipoprotein's non-polar core. This partitioning was described by overall affinity constants of 1.2 (± 0.3) × 106 M-1 for R-propranolol and 2.4 (± 0.6) × 106 M-1 for S-propranolol at pH 7.4 and 37 °C. The second mechanism occurred through saturable binding by these drugs at fixed sites on VLDL, such as represented by apolipoproteins on the surface of the lipoprotein. The association equilibrium constants for this saturable binding at 37 °C were 7.0 (± 2.3) × 104 M-1 for R-propranolol and 9.6 (± 2.2) × 104 M-1 for S-propranolol. Comparable results were obtained at 20 °C and 27 °C for the propranolol enantiomers. This work provided fundamental information on the processes involved in the binding of R- and S-propranolol to VLDL, while also illustrating how HPAC can be used to evaluate relatively complex interactions between agents such as VLDL and drugs or other solutes.

Modeling the Distribution of Diprotic Basic Drugs in Liposomal Systems: Perspectives on Malaria Nanotherapy

“…This particular subcellular distribution is attractive because it would contribute to preventing the easy exchange of drug molecules with circulating structures (e.g., other cells and high-/low-density lipoproteins) (Fahr et al, 2005; Hefesha et al, 2011; Loew et al, 2011), as well as a potential loss of drug function due to its degradation in both extracellular (blood plasma and body tissues) and cytoplasmic aqueous environments (Waterman et al, 2002). Our models omit the participation of other circulating organic bodies and particles that are known to affect drug distribution in vivo , such as plasma lipoproteins and albumin aggregates (Yamasaki et al, 2013; Sobansky and Hage, 2014), though point out at the remarkable potential of RBCs as vascular carriers and prompt the utilization of ex vivo RBC loading techniques for drug delivery-based therapeutics (Zhou et al, 2010; Biagiotti et al, 2011; Villa et al, 2016).…”

“…A further optimization of the vesicular model presented here is required for a more accurate representation of a clinical scenario. Plasma components are known to interact with circulating drugs (Yamasaki et al, 2013; Sobansky and Hage, 2014), and these additionally present large biodistribution volumes broadly diffusing across animal tissues.…”

Analysis of Biological Interactions by Affinity Chromatography: Clinical and Pharmaceutical Applications

“…Further work in the miniaturization of affinity columns and systems is also anticipated (5,10,23,37). This work has already led to the possibility of carrying out binding studies on relatively exotic binding agents (e.g., lipoproteins, receptors or modified forms of proteins) and even binding agents that have been obtained from individual patients (e.g., glycated HSA) (14–16,25–27,36). These efforts, in turn, have resulted in the proposed use of HPAC as a tool in personalized medicine (25).…”

“…The data obtained by frontal analysis indicated that a simple non-saturable binding model (e.g., partitioning into the non-polar core of LDL) was present in the case of S -propranolol, while a mixture of saturable binding and non-saturable interactions was present for R -propranolol (e.g., binding with apolipoproteins plus partitioning into LDL) (14). A similar approach has been used to study the interactions of R/S -propranolol and verapamil with high-density lipoprotein (15) and the binding of R/S -propanolol with very low-density lipoprotein (16). HPAC and affinity chromatography have also been employed in examining the binding of various solutes and drugs with the transport proteins α 1 -acid glycoprotein (AGP) or human serum albumin (HSA) (10,17,18), the binding of urediofibrate-like dual agonists with peroxisome proliferator-activated receptors (19), and the interactions of many compounds with immobilized enzymes or lectins (12,20–22).…”

Analysis of stereoselective drug interactions with serum proteins by high-performance affinity chromatography: A historical perspective

“…Recent work with HPAC and lipoprotein columns have shown that drugs can interact with these binding agents through several possible mechanisms, including both partitioning into the hydrophobic core and saturable interactions (e.g., with sites on apolipoproteins) [81–83]. Both of these processes have been noted for propranolol with HDL, LDL or VLDL, as well as for verapamil with HDL [81–84].…”