Impedes systemic absorption

Impedes systemic absorption" describes any process, agent, or physiological barrier that **delays, reduces, or blocks the entry of drugs or substances into systemic circulation from the site of administration**. This may involve structural barriers (e.g., tight junctions in the blood-brain barrier or corneal epithelium[1][3]), physiochemical properties of a formulation (such as large molecular size, low lipid solubility, or depot preparations[1][2]), or incorporation of excipients (like vasoconstrictors or oils) in drug delivery systems to slow absorption rates[1]. It is not a molecular target but a descriptive term for pharmaceutical or anatomical features affecting drug bioavailability. This entry is not a valid molecular target and likely results from a misunderstanding or incorrect input.