Electrochemical Study of Drug Interactions

Abstract

Drug interactions based on molecular association between drug molecules and molecules of other drugs or molecules of the biosphere, are of considerable clinical importance. Unfortunately, much of the literature is of questionable validity because arguments based on expectation, or extrapolation, are presented without adequate experimental confirmation. Conductometric titration is one technique by which ionic association may be demonstrated. Application of the technique is limited however by metabolic transformation of drugs, displacement of molecular associations by biological substances such as plasma proteins, and distribution into the various body “compartments”. In spite of these limitations however, certain drugs are suitable for investigation by conductometric methods. One example is the anticoagulant heparin which appears to act in the blood plasma without metabolic modification and by a mechanism which depends on the anionic charge of the drug molecule. Furthermore, the “in vivo” reversal of the anticoagulant action of heparin by the cationic protamine sulphate is well known and used clinically. Possible interactions between heparin and other drugs have been investigated and the results compared with the current pharmaceutical literature.