Coupled High-Performance Capillary Electrophoresis and Fronal analysis for ultramicro Binding study of certain drugs with Plasma Lipoproteins

SUMMARY AND CONCLUSIONSStudies on the protein binding of cationic drugs suggested that, in some acute clinical conditions, drug therapy is more effectively monitored by free drug levels. This is especially true for ealcium channel blockers e.g. verapamil (VER) and nilvadipine (NV) and B-blocker propranolol (PRO) this work was undertaken fundamentally to evoke a suitable reliable method for studying the binding of these drugs with plasma lipoproteins and for monitoring their free plasma levels. Capillary electrophoresis coupled with frontal analysis (HPCE\FA) was applied to the ultramicro and enantiosclective binding study of plasma lipoproteins to PRO, VER and NV. The drug – lipoprotein mixed solution was introduced hydrodynamically into non-coated fused silica capillary. Due to electroosmotic flow, unbound drug enatiomer s- or –R, aneutral or positively charged comhpound, migrates toward cathodic end faster than negatively charged and the bound form. Once unbound drug migrates apart from lipoprotein, the bound drug is quickly released from the protein to maintain the binding equilibrium. Then, the drug migrates as a zone with a plateau region, and the concentration in this plateau region is the same as the unbound drug concentration in the samples solution.The factors which affect on the application of HPCE\FA were optimized. These factors include, effect of voltage, effect of sample injection time and the velocity of LDL and HDL.