Author : Aman Romesh Khanna, Jignesh L. Patel
The process of new drug development requires extensive non-clinical safety testing in order to generate sufficient data to move to clinical development and then for market entry. Not only clinical development, but also non-clinical safety and pharmacology testing are time consuming, costly and require lot of resources. Many-times, after clearing non-clinical safety and pharmacology testing, the drug candidate may fail to demonstrate desired pharmacokinetic in clinical development phase. Suboptimal pharmacokinetic is one of the reasons for failure of the drug in demonstrating desired clinical efficacy and safety in later clinical development phase. Therefore, it is very important to have idea of pharmacokinetic of the drug candidate in human at least to make early “go/no-go” decision during development in order to reduce the time and cost of development. Microdosing is a new technique to obtain human pharmacokinetic information before the usual expensive clinical phase of drug development starts. Microdose studies uses less than 1/100th of the dose calculated to yield a pharmacological effect of the drug and hence, risk to trial subject is very less in microdose studies and it can be initiated early after completing limited non-clinical studies. It uses highly sensitive and specific analytical methods for estimating drug and metabolite concentrations in picogram to fentogram range. Experience of various drug developers with microdose studies so far suggests that microdosing is a better tool for predicting human pharmacokinetics early and may be helpful in order to make early “go/nogo” decision in drug development.