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. 2022 Oct 27;13(11):1691–1698. doi: 10.1021/acsmedchemlett.2c00375

Table 2. Pharmacokinetic and Safety Profile Comparison across Different Chemical Modalities.

chemical modality route of administration dosing frequency %F (bioavailability) Tmax (SC or IM) Vd (volume of distribution) metabolism
small molecule (SM) primarily oral often once a day generally good variable generally high; broad distribution to organs and tissues including CNS primarily by CYP and phase II enzymes
bRo5 SM emerging examples of orally bioavailable daily to weekly few examples of orally bioavailable variable mostly peripheral distribution variable depending on functional groups
bRo5 cyclopeptides/macrocycles emerging examples of orally bioavailable daily to weekly few examples of orally bioavailable variable mostly peripheral distribution mainly proteolytic enzymes
large peptides not orally bioavailable; mainly IV, SC weekly to monthly good for SC variable peripheral distribution proteolytic enzymes
oligonucleotide ASO not orally bioavailable; IV, SC, IT, and IVT weekly to monthly good for SC 0.25–5 h after SC high; broad distribution to kidneys and liver by nucleases
oligonucleotide siRNA not orally bioavailable; IV, SC, IT, and IVT weekly to once every 3–6 months not reported not reported broad distribution to kidneys and liver by nucleases
biologics (antibodies) not orally bioavailable; mainly IV, SC, and IM weekly to monthly good for SC and IM 1–8 days after SC or IM low; often limited to plasma and extracellular fluids catabolized by proteolytic enzymes