Parent drug or metabolite?Are the relevant analytes limited to the parent drug, or should metabolites, degradation products, or active intracellular forms also be included?
Renal clearance involved?Does the drug require urine-based analysis because renal excretion is a major disposition route?
Tissue penetration?Is tissue exposure important for evaluating drug concentration at infection-related sites?
Active intracellular forms?Do antiviral or related compounds require intracellular active metabolite or phosphorylated-form analysis?
Degradation products?Are instability or hydrolysis products likely to interfere with accurate parent-drug quantification?
Biomarker-linked response?Are host-response markers, pathogen-associated readouts, cytokines, bacterial burden, or viral load needed alongside exposure data?