The plasma protein binding of basic drugs.

The plasma protein binding of basic drugs appears to vary more than was at first assumed and is related to the marked intra-and interindividual differences in one of the chief binding proteins, AAG. Changes in AAG concentrations will result in alterations in the distribution and metabolism of basic drugs which will complicate the interpretation of the relationship between total drug concentration and drug efficacy or toxicity. For some drugs, e.g. lignocaine, direct measurement of free concentrations may improve their clinical use but rapid and reliable techniques are as yet not readily available.