PCL201H1 Lecture 7: Lecture 7 Absorption Barriers
Document Summary
Extent of ionization (ionization decreases change of passing though membrane). Physical properties of drugs: lipid solubility, partition coefficient (polarity) Charged or uncharged at specific ph and pka: molecular size/shape, avogadro"s number 1. 6 x 1024 da, most drugs (nonpeptides) are fairly small, peptides 1000-2000da, small proteins 6000 da and others 1000s of kda. Physical or anatomical factors: drugs must cross through multiple membranes. Transport or functional factors: drugs must overcome these barriers in order to be effective. Review: the cell: single cel: plasma membrane and nuclear membrane, phospholipids, proteins, unstirred water layer, glycosylation charges associated. Intercellular spaces completely blocked sometimes receptor mediated or nonspecific (pinocytosis: capillaries with maculae (noncontinuous junction; allows for transport, macular junctions are not continuous b, drugs ~500da ~100kda may move through maculae. A major issue in drug targeting: the bbb: even though there are exceptions, majority of compounds excluded from cns via.