Isoelectric focusing and capillary zone electrophoretic studies using luteinizing hormone releasing hormone and its analog.

Iontophoresis is the movement of charged compounds into and through the skin under an external electromotive force. A molecule's charge and size, as well as other factors, will determine its ability to be iontophoresed. One can gain insight into certain electrical aspects of a molecule by determining its isoelectric point as well as its electrophoretic mobility. In the present study, isoelectric focusing and capillary zone electrophoretic studies of luteinizing hormone releasing hormone, (LHRH) and one of its analogs are performed in order to predict their ability to be iontophoresed. The pI of LHRH is determined to be 9.6 while that of its free acid is 6.9. In addition, it is concluded that although the two compounds are chemically similar, the native compound is more mobile at pH > 2.5. These results suggest that the native compound might be better suited for iontophoretic delivery than is the free-acid analog.