Analysis of information sources in references of the Wikipedia article "Small molecule" in English language version.
The majority of [oral] drugs from the general reference set have molecular weights below 550. In contrast the molecular-weight distribution of oral antibacterial agents is bimodal: 340–450 Da but with another group in the 700–900 molecular weight range.
Table 5.13: Route of Administration: Small Molecules: oral administration usually possible; Biomolecules: Usually administered parenterally
Table 5.13: Route of Administration: Small Molecules: oral administration usually possible; Biomolecules: Usually administered parenterally