Monitoring compliance through analysis of drug and metabolite levels

Cold analytical methodology is usually available for drug and metabolite monitoring during clinical trials, since a procedure is required for the bioavailability, pharmacokinetic, and dose proportionality studies that must be conducted by the sponsor. Such methods can and have been applied to monitoring patient compliance. Examples from several classes of drugs with different pharmacokinetic profiles illustrate the type of data that can be obtained, along with their applicability and inherent limitation in assessing compliance. The effects of concomitant medication, drug half-life, volume of distribution, and sampling time on observed levels are also discussed. Several other approaches involving trace metals, microtaggants, and an electronic monitor are also presented.